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SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION (Details) (USD $)
 12 Months Ended
Apr. 30, 2013
Apr. 30, 2012
Apr. 30, 2011
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances $ 1,049,206,000 [1]    
Initial Cost to Company [Abstract]      
Land 223,909,000    
Buildings & Improvements 1,604,380,000    
Costs capitalized subsequent to acquisition 272,695,000    
Gross amount at which carried at close of period [Abstract]      
Land 241,909,000    
Buildings & Improvements 1,859,075,000    
Total 2,100,984,000    
Accumulated Depreciation (420,421,000)    
Maximum borrowing capacity 60,000,000    
Advances under the facility specified as percentage of value of properties provided as security (in hundredths) 60.00%    
Reconciliations of total real estate carrying value [Abstract]      
Balance at beginning of year 1,892,009,000 [2] 1,770,798,000 [2] 1,800,519,000
Additions during year [Abstract]      
Improvements and Other 36,375,000 35,176,000 23,183,000
Total Additions 2,060,505,000 1,903,131,000 1,865,080,000
Deductions during year [Abstract]      
Cost of real estate sold (21,953,000) (3,498,000) (86,994,000)
Impairment charge (305,000) (127,000) 0
Other (5,277,000) [3] (7,497,000) [3] (7,288,000) [3]
Balance at close of year 2,032,970,000 [2] 1,892,009,000 [2] 1,770,798,000 [2]
Reconciliations of accumulated depreciation/amortization [Abstract]      
Balance at beginning of year 373,490,000 328,952,000 308,626,000
Additions during year [Abstract]      
Provisions for depreciation 56,611,000 51,093,000 49,375,000
Deductions during year [Abstract]      
Accumulated depreciation on real estate sold (6,444,000) (758,000) (25,366,000)
Other (3,236,000) [4] (5,797,000) [4] (3,683,000) [4]
Balance at close of year 420,421,000 373,490,000 328,952,000
Net basis of real estate investments for federal income tax purposes 1,500,000,000 1,400,000,000 1,200,000,000
Multi-Family Residential [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 376,225,000 [1]    
Initial Cost to Company [Abstract]      
Land 46,532,000    
Buildings & Improvements 504,983,000    
Costs capitalized subsequent to acquisition 108,181,000    
Gross amount at which carried at close of period [Abstract]      
Land 57,889,000    
Buildings & Improvements 601,807,000    
Total 659,696,000    
Accumulated Depreciation (140,354,000)    
Additions during year [Abstract]      
Additions 113,859,000 47,433,000 4,210,000
Multi-Family Residential [Member] | 11th Street 3 Plex - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 90,000 [1]    
Initial Cost to Company [Abstract]      
Land 11,000    
Buildings & Improvements 53,000    
Costs capitalized subsequent to acquisition 12,000    
Gross amount at which carried at close of period [Abstract]      
Land 16,000    
Buildings & Improvements 60,000    
Total 76,000    
Accumulated Depreciation (8,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | 4th Street 4 Plex - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 104,000 [1]    
Initial Cost to Company [Abstract]      
Land 15,000    
Buildings & Improvements 74,000    
Costs capitalized subsequent to acquisition 21,000    
Gross amount at which carried at close of period [Abstract]      
Land 23,000    
Buildings & Improvements 87,000    
Total 110,000    
Accumulated Depreciation (11,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Apartments on Main - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 688,000 [1]    
Initial Cost to Company [Abstract]      
Land 158,000    
Buildings & Improvements 1,123,000    
Costs capitalized subsequent to acquisition 24,000    
Gross amount at which carried at close of period [Abstract]      
Land 179,000    
Buildings & Improvements 1,126,000    
Total 1,305,000    
Accumulated Depreciation (164,000)    
Year of Construction or Acquisition 1987    
Multi-Family Residential [Member] | Apartments on Main - Minot, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 24 years    
Multi-Family Residential [Member] | Apartments on Main - Minot, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Arbors - S Sioux City, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,000,000 [1]    
Initial Cost to Company [Abstract]      
Land 350,000    
Buildings & Improvements 6,625,000    
Costs capitalized subsequent to acquisition 1,281,000    
Gross amount at which carried at close of period [Abstract]      
Land 614,000    
Buildings & Improvements 7,642,000    
Total 8,256,000    
Accumulated Depreciation (1,522,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Ashland - Grand Forks, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,710,000 [1]    
Initial Cost to Company [Abstract]      
Land 741,000    
Buildings & Improvements 7,569,000    
Costs capitalized subsequent to acquisition 46,000    
Gross amount at which carried at close of period [Abstract]      
Land 756,000    
Buildings & Improvements 7,600,000    
Total 8,356,000    
Accumulated Depreciation (247,000)    
Year of Construction or Acquisition 2012    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Boulder Court - Eagan, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,231,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,067,000    
Buildings & Improvements 5,498,000    
Costs capitalized subsequent to acquisition 2,596,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,293,000    
Buildings & Improvements 7,868,000    
Total 9,161,000    
Accumulated Depreciation (2,007,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Brookfield Village - Topeka, KS [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,385,000 [1]    
Initial Cost to Company [Abstract]      
Land 509,000    
Buildings & Improvements 6,698,000    
Costs capitalized subsequent to acquisition 1,269,000    
Gross amount at which carried at close of period [Abstract]      
Land 635,000    
Buildings & Improvements 7,841,000    
Total 8,476,000    
Accumulated Depreciation (1,957,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Brooklyn Heights - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 800,000 [1]    
Initial Cost to Company [Abstract]      
Land 145,000    
Buildings & Improvements 1,450,000    
Costs capitalized subsequent to acquisition 785,000    
Gross amount at which carried at close of period [Abstract]      
Land 206,000    
Buildings & Improvements 2,174,000    
Total 2,380,000    
Accumulated Depreciation (804,000)    
Year of Construction or Acquisition 1997    
Multi-Family Residential [Member] | Brooklyn Heights - Minot, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 12 years    
Multi-Family Residential [Member] | Brooklyn Heights - Minot, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Campus Center - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,280,000 [1]    
Initial Cost to Company [Abstract]      
Land 395,000    
Buildings & Improvements 2,244,000    
Costs capitalized subsequent to acquisition 171,000    
Gross amount at which carried at close of period [Abstract]      
Land 400,000    
Buildings & Improvements 2,410,000    
Total 2,810,000    
Accumulated Depreciation (388,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Campus Heights - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 110,000    
Buildings & Improvements 628,000    
Costs capitalized subsequent to acquisition 72,000    
Gross amount at which carried at close of period [Abstract]      
Land 122,000    
Buildings & Improvements 688,000    
Total 810,000    
Accumulated Depreciation (113,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Campus Knoll - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 853,000 [1]    
Initial Cost to Company [Abstract]      
Land 266,000    
Buildings & Improvements 1,512,000    
Costs capitalized subsequent to acquisition 96,000    
Gross amount at which carried at close of period [Abstract]      
Land 273,000    
Buildings & Improvements 1,601,000    
Total 1,874,000    
Accumulated Depreciation (263,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Campus Plaza - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 54,000 [5]    
Buildings & Improvements 311,000 [5]    
Costs capitalized subsequent to acquisition 45,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 59,000 [5]    
Buildings & Improvements 351,000 [5]    
Total 410,000 [5]    
Accumulated Depreciation (59,000) [5]    
Year of Construction or Acquisition 2007 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Multi-Family Residential [Member] | Campus Side - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 107,000 [5]    
Buildings & Improvements 615,000 [5]    
Costs capitalized subsequent to acquisition 85,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 116,000 [5]    
Buildings & Improvements 691,000 [5]    
Total 807,000 [5]    
Accumulated Depreciation (115,000) [5]    
Year of Construction or Acquisition 2007 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Multi-Family Residential [Member] | Campus View - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 107,000 [5]    
Buildings & Improvements 615,000 [5]    
Costs capitalized subsequent to acquisition 79,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 111,000 [5]    
Buildings & Improvements 690,000 [5]    
Total 801,000 [5]    
Accumulated Depreciation (112,000) [5]    
Year of Construction or Acquisition 2007 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Multi-Family Residential [Member] | Canyon Lake - Rapid City, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,942,000 [1]    
Initial Cost to Company [Abstract]      
Land 305,000    
Buildings & Improvements 3,958,000    
Costs capitalized subsequent to acquisition 1,009,000    
Gross amount at which carried at close of period [Abstract]      
Land 361,000    
Buildings & Improvements 4,911,000    
Total 5,272,000    
Accumulated Depreciation (1,357,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Castlerock - Billings, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 6,773,000 [1]    
Initial Cost to Company [Abstract]      
Land 736,000    
Buildings & Improvements 4,864,000    
Costs capitalized subsequent to acquisition 1,816,000    
Gross amount at which carried at close of period [Abstract]      
Land 961,000    
Buildings & Improvements 6,455,000    
Total 7,416,000    
Accumulated Depreciation (2,267,000)    
Year of Construction or Acquisition 1998    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Chateau I -Minot ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 61,000    
Buildings & Improvements 5,663,000    
Costs capitalized subsequent to acquisition 326,000    
Gross amount at which carried at close of period [Abstract]      
Land 61,000    
Buildings & Improvements 5,989,000    
Total 6,050,000    
Accumulated Depreciation (359,000)    
Year of Construction or Acquisition 2013    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Cimarron Hills - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,879,000 [1]    
Initial Cost to Company [Abstract]      
Land 706,000    
Buildings & Improvements 9,588,000    
Costs capitalized subsequent to acquisition 4,128,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,279,000    
Buildings & Improvements 13,143,000    
Total 14,422,000    
Accumulated Depreciation (3,948,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Colonial Villa - Burnsville, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 6,461,000 [1]    
Initial Cost to Company [Abstract]      
Land 2,401,000    
Buildings & Improvements 11,515,000    
Costs capitalized subsequent to acquisition 4,259,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,797,000    
Buildings & Improvements 15,378,000    
Total 18,175,000    
Accumulated Depreciation (3,941,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Colony Lincoln, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 13,817,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,515,000    
Buildings & Improvements 15,731,000    
Costs capitalized subsequent to acquisition 107,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,526,000    
Buildings & Improvements 15,827,000    
Total 17,353,000    
Accumulated Depreciation (365,000)    
Year of Construction or Acquisition 2012    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Colton Heights - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 450,000 [1]    
Initial Cost to Company [Abstract]      
Land 80,000    
Buildings & Improvements 672,000    
Costs capitalized subsequent to acquisition 392,000    
Gross amount at which carried at close of period [Abstract]      
Land 114,000    
Buildings & Improvements 1,030,000    
Total 1,144,000    
Accumulated Depreciation (697,000)    
Year of Construction or Acquisition 1984    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Cornerstone - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 54,000 [5]    
Buildings & Improvements 311,000 [5]    
Costs capitalized subsequent to acquisition 48,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 55,000 [5]    
Buildings & Improvements 358,000 [5]    
Total 413,000 [5]    
Accumulated Depreciation (60,000) [5]    
Year of Construction or Acquisition 2007 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Multi-Family Residential [Member] | Cottage West Twin Homes - Sioux Falls, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,704,000 [1]    
Initial Cost to Company [Abstract]      
Land 968,000    
Buildings & Improvements 3,762,000    
Costs capitalized subsequent to acquisition 320,000    
Gross amount at which carried at close of period [Abstract]      
Land 991,000    
Buildings & Improvements 4,059,000    
Total 5,050,000    
Accumulated Depreciation (155,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Cottonwood - Bismarck, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 16,007,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,056,000    
Buildings & Improvements 17,372,000    
Costs capitalized subsequent to acquisition 2,969,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,345,000    
Buildings & Improvements 20,052,000    
Total 21,397,000    
Accumulated Depreciation (5,812,000)    
Year of Construction or Acquisition 1997    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Country Meadows - Billings, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 6,790,000 [1]    
Initial Cost to Company [Abstract]      
Land 491,000    
Buildings & Improvements 7,809,000    
Costs capitalized subsequent to acquisition 1,210,000    
Gross amount at which carried at close of period [Abstract]      
Land 534,000    
Buildings & Improvements 8,976,000    
Total 9,510,000    
Accumulated Depreciation (3,241,000)    
Year of Construction or Acquisition 1995    
Multi-Family Residential [Member] | Country Meadows - Billings, MT [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 33 years    
Multi-Family Residential [Member] | Country Meadows - Billings, MT [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Crestview - Bismarck, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,990,000 [1]    
Initial Cost to Company [Abstract]      
Land 235,000    
Buildings & Improvements 4,290,000    
Costs capitalized subsequent to acquisition 1,422,000    
Gross amount at which carried at close of period [Abstract]      
Land 494,000    
Buildings & Improvements 5,453,000    
Total 5,947,000    
Accumulated Depreciation (2,571,000)    
Year of Construction or Acquisition 1994    
Multi-Family Residential [Member] | Crestview - Bismarck, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 24 years    
Multi-Family Residential [Member] | Crestview - Bismarck, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Crown - Rochester, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,687,000 [1]    
Initial Cost to Company [Abstract]      
Land 261,000    
Buildings & Improvements 3,289,000    
Costs capitalized subsequent to acquisition 171,000    
Gross amount at which carried at close of period [Abstract]      
Land 266,000    
Buildings & Improvements 3,455,000    
Total 3,721,000    
Accumulated Depreciation (270,000)    
Year of Construction or Acquisition 2010    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Crown Colony - Topeka, KS [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,350,000 [1]    
Initial Cost to Company [Abstract]      
Land 620,000    
Buildings & Improvements 9,956,000    
Costs capitalized subsequent to acquisition 2,010,000    
Gross amount at which carried at close of period [Abstract]      
Land 817,000    
Buildings & Improvements 11,769,000    
Total 12,586,000    
Accumulated Depreciation (3,897,000)    
Year of Construction or Acquisition 1999    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | East Park - Sioux Falls, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 115,000    
Buildings & Improvements 2,405,000    
Costs capitalized subsequent to acquisition 728,000    
Gross amount at which carried at close of period [Abstract]      
Land 156,000    
Buildings & Improvements 3,092,000    
Total 3,248,000    
Accumulated Depreciation (921,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Evergreen - Isanti, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,049,000 [1]    
Initial Cost to Company [Abstract]      
Land 380,000    
Buildings & Improvements 2,740,000    
Costs capitalized subsequent to acquisition 64,000    
Gross amount at which carried at close of period [Abstract]      
Land 380,000    
Buildings & Improvements 2,804,000    
Total 3,184,000    
Accumulated Depreciation (324,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Evergreen II - Isanti, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,148,000 [1]    
Initial Cost to Company [Abstract]      
Land 691,000    
Buildings & Improvements 2,784,000    
Costs capitalized subsequent to acquisition 9,000    
Gross amount at which carried at close of period [Abstract]      
Land 691,000    
Buildings & Improvements 2,793,000    
Total 3,484,000    
Accumulated Depreciation (117,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Fairmont - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 356,000 [1]    
Initial Cost to Company [Abstract]      
Land 28,000    
Buildings & Improvements 337,000    
Costs capitalized subsequent to acquisition 51,000    
Gross amount at which carried at close of period [Abstract]      
Land 53,000    
Buildings & Improvements 363,000    
Total 416,000    
Accumulated Depreciation (48,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | First Avenue - Minot ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 0    
Buildings & Improvements 2,677,000    
Costs capitalized subsequent to acquisition 232,000    
Gross amount at which carried at close of period [Abstract]      
Land 0    
Buildings & Improvements 2,909,000    
Total 2,909,000    
Accumulated Depreciation (3,000)    
Year of Construction or Acquisition 2013    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Forest Park - Grand Forks, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 7,816,000 [1]    
Initial Cost to Company [Abstract]      
Land 810,000    
Buildings & Improvements 5,579,000    
Costs capitalized subsequent to acquisition 6,554,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,365,000    
Buildings & Improvements 11,578,000    
Total 12,943,000    
Accumulated Depreciation (4,462,000)    
Year of Construction or Acquisition 1993    
Multi-Family Residential [Member] | Forest Park - Grand Forks, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 24 years    
Multi-Family Residential [Member] | Forest Park - Grand Forks, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Gables Townhomes - Sioux Falls, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,499,000 [1]    
Initial Cost to Company [Abstract]      
Land 349,000    
Buildings & Improvements 1,921,000    
Costs capitalized subsequent to acquisition 134,000    
Gross amount at which carried at close of period [Abstract]      
Land 366,000    
Buildings & Improvements 2,038,000    
Total 2,404,000    
Accumulated Depreciation (79,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Grand Gateway - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,580,000 [1]    
Initial Cost to Company [Abstract]      
Land 814,000    
Buildings & Improvements 7,086,000    
Costs capitalized subsequent to acquisition 353,000    
Gross amount at which carried at close of period [Abstract]      
Land 909,000    
Buildings & Improvements 7,344,000    
Total 8,253,000    
Accumulated Depreciation (256,000)    
Year of Construction or Acquisition 2012    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Greenfield - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,642,000 [1]    
Initial Cost to Company [Abstract]      
Land 578,000    
Buildings & Improvements 4,122,000    
Costs capitalized subsequent to acquisition 586,000    
Gross amount at which carried at close of period [Abstract]      
Land 775,000    
Buildings & Improvements 4,511,000    
Total 5,286,000    
Accumulated Depreciation (641,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Heritage Manor - Rochester, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,198,000 [1]    
Initial Cost to Company [Abstract]      
Land 403,000    
Buildings & Improvements 6,968,000    
Costs capitalized subsequent to acquisition 2,422,000    
Gross amount at which carried at close of period [Abstract]      
Land 480,000    
Buildings & Improvements 9,313,000    
Total 9,793,000    
Accumulated Depreciation (3,206,000)    
Year of Construction or Acquisition 1998    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Indian Hills - Sioux City, IA [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 294,000 [5]    
Buildings & Improvements 2,921,000 [5]    
Costs capitalized subsequent to acquisition 3,309,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 375,000 [5]    
Buildings & Improvements 6,149,000 [5]    
Total 6,524,000 [5]    
Accumulated Depreciation (944,000) [5]    
Year of Construction or Acquisition 2007 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Multi-Family Residential [Member] | Kirkwood Manor - Bismarck, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,361,000 [1]    
Initial Cost to Company [Abstract]      
Land 449,000    
Buildings & Improvements 2,725,000    
Costs capitalized subsequent to acquisition 1,443,000    
Gross amount at which carried at close of period [Abstract]      
Land 546,000    
Buildings & Improvements 4,071,000    
Total 4,617,000    
Accumulated Depreciation (1,528,000)    
Year of Construction or Acquisition 1997    
Multi-Family Residential [Member] | Kirkwood Manor - Bismarck, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 12 years    
Multi-Family Residential [Member] | Kirkwood Manor - Bismarck, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Lakeside Village Lincoln, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 13,625,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,215,000    
Buildings & Improvements 15,837,000    
Costs capitalized subsequent to acquisition 88,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,216,000    
Buildings & Improvements 15,924,000    
Total 17,140,000    
Accumulated Depreciation (365,000)    
Year of Construction or Acquisition 2012    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Lancaster - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 762,000 [1]    
Initial Cost to Company [Abstract]      
Land 289,000    
Buildings & Improvements 2,899,000    
Costs capitalized subsequent to acquisition 981,000    
Gross amount at which carried at close of period [Abstract]      
Land 451,000    
Buildings & Improvements 3,718,000    
Total 4,169,000    
Accumulated Depreciation (1,329,000)    
Year of Construction or Acquisition 2000    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Landmark - Grand Forks, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,700,000 [1]    
Initial Cost to Company [Abstract]      
Land 184,000    
Buildings & Improvements 1,514,000    
Costs capitalized subsequent to acquisition 904,000    
Gross amount at which carried at close of period [Abstract]      
Land 277,000    
Buildings & Improvements 2,325,000    
Total 2,602,000    
Accumulated Depreciation (896,000)    
Year of Construction or Acquisition 1997    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Legacy - Grand Forks, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 16,222,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,362,000    
Buildings & Improvements 21,727,000    
Costs capitalized subsequent to acquisition 5,870,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,080,000    
Buildings & Improvements 26,879,000    
Total 28,959,000    
Accumulated Depreciation (8,591,000)    
Multi-Family Residential [Member] | Legacy - Grand Forks, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Year of Construction or Acquisition 1995    
Life on which depreciation in latest income statement is computed 24 years    
Multi-Family Residential [Member] | Legacy - Grand Forks, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Mariposa - Topeka, KS [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,022,000 [1]    
Initial Cost to Company [Abstract]      
Land 399,000    
Buildings & Improvements 5,110,000    
Costs capitalized subsequent to acquisition 392,000    
Gross amount at which carried at close of period [Abstract]      
Land 422,000    
Buildings & Improvements 5,479,000    
Total 5,901,000    
Accumulated Depreciation (1,185,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Meadows - Jamestown, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 590,000 [5]    
Buildings & Improvements 4,519,000 [5]    
Costs capitalized subsequent to acquisition 1,200,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 653,000 [5]    
Buildings & Improvements 5,656,000 [5]    
Total 6,309,000 [5]    
Accumulated Depreciation (1,811,000) [5]    
Year of Construction or Acquisition 1998 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Multi-Family Residential [Member] | Monticello Village - Monticello, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,886,000 [1]    
Initial Cost to Company [Abstract]      
Land 490,000    
Buildings & Improvements 3,756,000    
Costs capitalized subsequent to acquisition 435,000    
Gross amount at which carried at close of period [Abstract]      
Land 621,000    
Buildings & Improvements 4,060,000    
Total 4,681,000    
Accumulated Depreciation (1,016,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | North Pointe - Bismarck, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,478,000 [1]    
Initial Cost to Company [Abstract]      
Land 303,000    
Buildings & Improvements 3,957,000    
Costs capitalized subsequent to acquisition 469,000    
Gross amount at which carried at close of period [Abstract]      
Land 336,000    
Buildings & Improvements 4,393,000    
Total 4,729,000    
Accumulated Depreciation (1,206,000)    
Multi-Family Residential [Member] | North Pointe - Bismarck, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Year of Construction or Acquisition 1995    
Life on which depreciation in latest income statement is computed 24 years    
Multi-Family Residential [Member] | North Pointe - Bismarck, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Northern Valley - Rochester, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 110,000    
Buildings & Improvements 610,000    
Costs capitalized subsequent to acquisition 64,000    
Gross amount at which carried at close of period [Abstract]      
Land 119,000    
Buildings & Improvements 665,000    
Total 784,000    
Accumulated Depreciation (54,000)    
Year of Construction or Acquisition 2010    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Oakmont Estates - Sioux Falls, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,524,000 [1]    
Initial Cost to Company [Abstract]      
Land 423,000    
Buildings & Improvements 4,838,000    
Costs capitalized subsequent to acquisition 450,000    
Gross amount at which carried at close of period [Abstract]      
Land 515,000    
Buildings & Improvements 5,196,000    
Total 5,711,000    
Accumulated Depreciation (1,464,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Oakwood Estates - Sioux Falls, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,107,000 [1]    
Initial Cost to Company [Abstract]      
Land 543,000    
Buildings & Improvements 2,784,000    
Costs capitalized subsequent to acquisition 4,134,000    
Gross amount at which carried at close of period [Abstract]      
Land 767,000    
Buildings & Improvements 6,694,000    
Total 7,461,000    
Accumulated Depreciation (2,830,000)    
Year of Construction or Acquisition 1993    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Olympic Village - Billings, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 10,955,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,164,000    
Buildings & Improvements 10,441,000    
Costs capitalized subsequent to acquisition 2,563,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,624,000    
Buildings & Improvements 12,544,000    
Total 14,168,000    
Accumulated Depreciation (4,061,000)    
Year of Construction or Acquisition 2000    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Olympik Village - Rochester, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,610,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,034,000    
Buildings & Improvements 6,109,000    
Costs capitalized subsequent to acquisition 1,493,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,154,000    
Buildings & Improvements 7,482,000    
Total 8,636,000    
Accumulated Depreciation (1,612,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Oxbow Park - Sioux Falls, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,011,000 [1]    
Initial Cost to Company [Abstract]      
Land 404,000    
Buildings & Improvements 3,152,000    
Costs capitalized subsequent to acquisition 2,468,000    
Gross amount at which carried at close of period [Abstract]      
Land 563,000    
Buildings & Improvements 5,461,000    
Total 6,024,000    
Accumulated Depreciation (2,446,000)    
Year of Construction or Acquisition 1994    
Multi-Family Residential [Member] | Oxbow Park - Sioux Falls, SD [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 24 years    
Multi-Family Residential [Member] | Oxbow Park - Sioux Falls, SD [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Park Meadows - Waite Park, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,581,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,143,000    
Buildings & Improvements 9,099,000    
Costs capitalized subsequent to acquisition 4,406,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,545,000    
Buildings & Improvements 13,103,000    
Total 14,648,000    
Accumulated Depreciation (5,283,000)    
Year of Construction or Acquisition 1997    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Pebble Springs - Bismarck, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 792,000 [1]    
Initial Cost to Company [Abstract]      
Land 7,000    
Buildings & Improvements 748,000    
Costs capitalized subsequent to acquisition 132,000    
Gross amount at which carried at close of period [Abstract]      
Land 44,000    
Buildings & Improvements 843,000    
Total 887,000    
Accumulated Depreciation (299,000)    
Year of Construction or Acquisition 1999    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Pinehurst - Billings, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 279,000 [1]    
Initial Cost to Company [Abstract]      
Land 72,000    
Buildings & Improvements 687,000    
Costs capitalized subsequent to acquisition 229,000    
Gross amount at which carried at close of period [Abstract]      
Land 77,000    
Buildings & Improvements 911,000    
Total 988,000    
Accumulated Depreciation (245,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Pines - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 128,000 [1]    
Initial Cost to Company [Abstract]      
Land 35,000    
Buildings & Improvements 215,000    
Costs capitalized subsequent to acquisition 181,000    
Gross amount at which carried at close of period [Abstract]      
Land 49,000    
Buildings & Improvements 382,000    
Total 431,000    
Accumulated Depreciation (121,000)    
Year of Construction or Acquisition 1997    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Plaza - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,602,000 [1]    
Initial Cost to Company [Abstract]      
Land 867,000    
Buildings & Improvements 12,784,000    
Costs capitalized subsequent to acquisition 2,246,000    
Gross amount at which carried at close of period [Abstract]      
Land 986,000    
Buildings & Improvements 14,911,000    
Total 15,897,000    
Accumulated Depreciation (1,635,000)    
Year of Construction or Acquisition 2009    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Pointe West - Rapid City, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,731,000 [1]    
Initial Cost to Company [Abstract]      
Land 240,000    
Buildings & Improvements 3,538,000    
Costs capitalized subsequent to acquisition 1,453,000    
Gross amount at which carried at close of period [Abstract]      
Land 363,000    
Buildings & Improvements 4,868,000    
Total 5,231,000    
Accumulated Depreciation (2,095,000)    
Year of Construction or Acquisition 1994    
Multi-Family Residential [Member] | Pointe West - Rapid City, SD [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 24 years    
Multi-Family Residential [Member] | Pointe West - Rapid City, SD [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Ponds at Heritage Place - Sartell, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,045,000 [1]    
Initial Cost to Company [Abstract]      
Land 395,000    
Buildings & Improvements 4,564,000    
Costs capitalized subsequent to acquisition 105,000    
Gross amount at which carried at close of period [Abstract]      
Land 395,000    
Buildings & Improvements 4,669,000    
Total 5,064,000    
Accumulated Depreciation (73,000)    
Year of Construction or Acquisition 2012    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Prairie Winds - Sioux Falls, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,464,000 [1]    
Initial Cost to Company [Abstract]      
Land 144,000    
Buildings & Improvements 1,816,000    
Costs capitalized subsequent to acquisition 436,000    
Gross amount at which carried at close of period [Abstract]      
Land 226,000    
Buildings & Improvements 2,170,000    
Total 2,396,000    
Accumulated Depreciation (1,107,000)    
Year of Construction or Acquisition 1993    
Multi-Family Residential [Member] | Prairie Winds - Sioux Falls, SD [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 24 years    
Multi-Family Residential [Member] | Prairie Winds - Sioux Falls, SD [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Quarry Ridge - Rochester, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 11,599,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,312,000    
Buildings & Improvements 13,362,000    
Costs capitalized subsequent to acquisition 964,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,347,000    
Buildings & Improvements 14,291,000    
Total 15,638,000    
Accumulated Depreciation (2,385,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Quarry Ridge 2 - Rochester, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 942,000    
Buildings & Improvements 16,677,000    
Costs capitalized subsequent to acquisition 19,000    
Gross amount at which carried at close of period [Abstract]      
Land 942,000    
Buildings & Improvements 16,696,000    
Total 17,638,000    
Accumulated Depreciation (385,000)    
Year of Construction or Acquisition 2012    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Regency Park Estates - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 6,966,000 [1]    
Initial Cost to Company [Abstract]      
Land 702,000    
Buildings & Improvements 10,198,000    
Costs capitalized subsequent to acquisition 638,000    
Gross amount at which carried at close of period [Abstract]      
Land 723,000    
Buildings & Improvements 10,815,000    
Total 11,538,000    
Accumulated Depreciation (474,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Ridge Oaks - Sioux City, IA [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,466,000 [1]    
Initial Cost to Company [Abstract]      
Land 178,000    
Buildings & Improvements 4,073,000    
Costs capitalized subsequent to acquisition 2,017,000    
Gross amount at which carried at close of period [Abstract]      
Land 272,000    
Buildings & Improvements 5,996,000    
Total 6,268,000    
Accumulated Depreciation (1,883,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Rimrock West - Billings, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,392,000 [1]    
Initial Cost to Company [Abstract]      
Land 330,000    
Buildings & Improvements 3,489,000    
Costs capitalized subsequent to acquisition 1,413,000    
Gross amount at which carried at close of period [Abstract]      
Land 431,000    
Buildings & Improvements 4,801,000    
Total 5,232,000    
Accumulated Depreciation (1,483,000)    
Year of Construction or Acquisition 1999    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Rocky Meadows - Billings, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,260,000 [1]    
Initial Cost to Company [Abstract]      
Land 656,000    
Buildings & Improvements 5,726,000    
Costs capitalized subsequent to acquisition 996,000    
Gross amount at which carried at close of period [Abstract]      
Land 767,000    
Buildings & Improvements 6,611,000    
Total 7,378,000    
Accumulated Depreciation (2,756,000)    
Year of Construction or Acquisition 1995    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Rum River - Isanti, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,677,000 [1]    
Initial Cost to Company [Abstract]      
Land 843,000    
Buildings & Improvements 4,823,000    
Costs capitalized subsequent to acquisition 105,000    
Gross amount at which carried at close of period [Abstract]      
Land 848,000    
Buildings & Improvements 4,923,000    
Total 5,771,000    
Accumulated Depreciation (749,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Sherwood - Topeka, KS [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 12,534,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,142,000    
Buildings & Improvements 14,684,000    
Costs capitalized subsequent to acquisition 2,729,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,590,000    
Buildings & Improvements 16,965,000    
Total 18,555,000    
Accumulated Depreciation (5,699,000)    
Year of Construction or Acquisition 1999    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Sierra Vista - Sioux Falls, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,450,000 [1]    
Initial Cost to Company [Abstract]      
Land 241,000    
Buildings & Improvements 2,097,000    
Costs capitalized subsequent to acquisition 322,000    
Gross amount at which carried at close of period [Abstract]      
Land 251,000    
Buildings & Improvements 2,409,000    
Total 2,660,000    
Accumulated Depreciation (129,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | South Pointe - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,954,000 [1]    
Initial Cost to Company [Abstract]      
Land 550,000    
Buildings & Improvements 9,548,000    
Costs capitalized subsequent to acquisition 2,351,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,305,000    
Buildings & Improvements 11,144,000    
Total 12,449,000    
Accumulated Depreciation (4,802,000)    
Year of Construction or Acquisition 1995    
Multi-Family Residential [Member] | South Pointe - Minot, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 24 years    
Multi-Family Residential [Member] | South Pointe - Minot, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Southview - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,082,000 [1]    
Initial Cost to Company [Abstract]      
Land 185,000    
Buildings & Improvements 469,000    
Costs capitalized subsequent to acquisition 314,000    
Gross amount at which carried at close of period [Abstract]      
Land 236,000    
Buildings & Improvements 732,000    
Total 968,000    
Accumulated Depreciation (313,000)    
Year of Construction or Acquisition 1994    
Multi-Family Residential [Member] | Southview - Minot, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 24 years    
Multi-Family Residential [Member] | Southview - Minot, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Southwind - Grand Forks, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,719,000 [1]    
Initial Cost to Company [Abstract]      
Land 400,000    
Buildings & Improvements 5,034,000    
Costs capitalized subsequent to acquisition 2,627,000    
Gross amount at which carried at close of period [Abstract]      
Land 719,000    
Buildings & Improvements 7,342,000    
Total 8,061,000    
Accumulated Depreciation (3,037,000)    
Year of Construction or Acquisition 1995    
Multi-Family Residential [Member] | Southwind - Grand Forks, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 24 years    
Multi-Family Residential [Member] | Southwind - Grand Forks, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Summit Park - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,110,000 [1]    
Initial Cost to Company [Abstract]      
Land 161,000    
Buildings & Improvements 1,898,000    
Costs capitalized subsequent to acquisition 1,145,000    
Gross amount at which carried at close of period [Abstract]      
Land 292,000    
Buildings & Improvements 2,912,000    
Total 3,204,000    
Accumulated Depreciation (1,064,000)    
Year of Construction or Acquisition 1997    
Multi-Family Residential [Member] | Summit Park - Minot, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 24 years    
Multi-Family Residential [Member] | Summit Park - Minot, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Sunset Trail - Rochester, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,259,000 [1]    
Initial Cost to Company [Abstract]      
Land 336,000    
Buildings & Improvements 12,814,000    
Costs capitalized subsequent to acquisition 2,322,000    
Gross amount at which carried at close of period [Abstract]      
Land 536,000    
Buildings & Improvements 14,936,000    
Total 15,472,000    
Accumulated Depreciation (4,572,000)    
Year of Construction or Acquisition 1999    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Sycamore Village - Sioux Falls, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 101,000    
Buildings & Improvements 1,317,000    
Costs capitalized subsequent to acquisition 470,000    
Gross amount at which carried at close of period [Abstract]      
Land 152,000    
Buildings & Improvements 1,736,000    
Total 1,888,000    
Accumulated Depreciation (536,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Temple - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 81,000 [1]    
Initial Cost to Company [Abstract]      
Land 0    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 228,000    
Gross amount at which carried at close of period [Abstract]      
Land 0    
Buildings & Improvements 228,000    
Total 228,000    
Accumulated Depreciation (42,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Terrace Heights - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 185,000 [1]    
Initial Cost to Company [Abstract]      
Land 29,000    
Buildings & Improvements 312,000    
Costs capitalized subsequent to acquisition 83,000    
Gross amount at which carried at close of period [Abstract]      
Land 40,000    
Buildings & Improvements 384,000    
Total 424,000    
Accumulated Depreciation (153,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Thomasbrook - Lincoln, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 6,076,000 [1]    
Initial Cost to Company [Abstract]      
Land 600,000    
Buildings & Improvements 10,306,000    
Costs capitalized subsequent to acquisition 2,871,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,151,000    
Buildings & Improvements 12,626,000    
Total 13,777,000    
Accumulated Depreciation (3,943,000)    
Year of Construction or Acquisition 1999    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | University Park Place - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 78,000 [5]    
Buildings & Improvements 450,000 [5]    
Costs capitalized subsequent to acquisition 73,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 80,000 [5]    
Buildings & Improvements 521,000 [5]    
Total 601,000 [5]    
Accumulated Depreciation (81,000) [5]    
Year of Construction or Acquisition 2007 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Multi-Family Residential [Member] | Valley Park - Grand Forks, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,946,000 [1]    
Initial Cost to Company [Abstract]      
Land 294,000    
Buildings & Improvements 4,137,000    
Costs capitalized subsequent to acquisition 2,674,000    
Gross amount at which carried at close of period [Abstract]      
Land 533,000    
Buildings & Improvements 6,572,000    
Total 7,105,000    
Accumulated Depreciation (2,178,000)    
Year of Construction or Acquisition 1999    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Villa West - Topeka, KS [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 12,446,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,590,000    
Buildings & Improvements 15,760,000    
Costs capitalized subsequent to acquisition 80,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,595,000    
Buildings & Improvements 15,835,000    
Total 17,430,000    
Accumulated Depreciation (393,000)    
Year of Construction or Acquisition 2012    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Village Green - Rochester, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,237,000 [1]    
Initial Cost to Company [Abstract]      
Land 234,000    
Buildings & Improvements 2,296,000    
Costs capitalized subsequent to acquisition 619,000    
Gross amount at which carried at close of period [Abstract]      
Land 357,000    
Buildings & Improvements 2,792,000    
Total 3,149,000    
Accumulated Depreciation (728,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | West Stonehill - Waite Park, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,783,000 [1]    
Initial Cost to Company [Abstract]      
Land 939,000    
Buildings & Improvements 10,167,000    
Costs capitalized subsequent to acquisition 4,654,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,378,000    
Buildings & Improvements 14,382,000    
Total 15,760,000    
Accumulated Depreciation (6,424,000)    
Year of Construction or Acquisition 1995    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Westridge - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,716,000 [1]    
Initial Cost to Company [Abstract]      
Land 68,000    
Buildings & Improvements 1,887,000    
Costs capitalized subsequent to acquisition 90,000    
Gross amount at which carried at close of period [Abstract]      
Land 74,000    
Buildings & Improvements 1,971,000    
Total 2,045,000    
Accumulated Depreciation (250,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Westwood Park - Bismarck, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,012,000 [1]    
Initial Cost to Company [Abstract]      
Land 116,000    
Buildings & Improvements 1,909,000    
Costs capitalized subsequent to acquisition 1,673,000    
Gross amount at which carried at close of period [Abstract]      
Land 260,000    
Buildings & Improvements 3,438,000    
Total 3,698,000    
Accumulated Depreciation (1,204,000)    
Year of Construction or Acquisition 1998    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Whispering Ridge - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 22,000,000 [1]    
Initial Cost to Company [Abstract]      
Land 2,139,000    
Buildings & Improvements 25,424,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 2,139,000    
Buildings & Improvements 25,424,000    
Total 27,563,000    
Accumulated Depreciation (82,000)    
Year of Construction or Acquisition 2012    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Williston Garden - Williston, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 13,523,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,400,000    
Buildings & Improvements 17,712,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 1,400,000    
Buildings & Improvements 17,712,000    
Total 19,112,000    
Accumulated Depreciation (704,000)    
Year of Construction or Acquisition 2012    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Winchester - Rochester, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,028,000 [1]    
Initial Cost to Company [Abstract]      
Land 748,000    
Buildings & Improvements 5,622,000    
Costs capitalized subsequent to acquisition 1,597,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,003,000    
Buildings & Improvements 6,964,000    
Total 7,967,000    
Accumulated Depreciation (1,839,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Multi-Family Residential [Member] | Woodridge - Rochester, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 6,560,000 [1]    
Initial Cost to Company [Abstract]      
Land 370,000    
Buildings & Improvements 6,028,000    
Costs capitalized subsequent to acquisition 1,754,000    
Gross amount at which carried at close of period [Abstract]      
Land 485,000    
Buildings & Improvements 7,667,000    
Total 8,152,000    
Accumulated Depreciation (3,103,000)    
Year of Construction or Acquisition 1997    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 343,753,000 [1]    
Initial Cost to Company [Abstract]      
Land 72,069,000    
Buildings & Improvements 472,083,000    
Costs capitalized subsequent to acquisition 69,623,000    
Gross amount at which carried at close of period [Abstract]      
Land 75,222,000    
Buildings & Improvements 538,553,000    
Total 613,775,000    
Accumulated Depreciation (138,270,000)    
Additions during year [Abstract]      
Additions 0 0 6,836,000
Commercial-Office [Member] | 1st Avenue Building - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 30,000    
Buildings & Improvements 80,000    
Costs capitalized subsequent to acquisition (41,000)    
Gross amount at which carried at close of period [Abstract]      
Land 33,000    
Buildings & Improvements 36,000    
Total 69,000    
Accumulated Depreciation 245,000    
Year of Construction or Acquisition 1981    
Commercial-Office [Member] | 1st Avenue Building - Minot, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 33 years    
Commercial-Office [Member] | 1st Avenue Building - Minot, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | 2030 Cliff Road - Eagan, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 967,000 [1]    
Initial Cost to Company [Abstract]      
Land 146,000    
Buildings & Improvements 835,000    
Costs capitalized subsequent to acquisition 90,000    
Gross amount at which carried at close of period [Abstract]      
Land 158,000    
Buildings & Improvements 913,000    
Total 1,071,000    
Accumulated Depreciation (273,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | 610 Business Center IV - Brooklyn Park, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 7,011,000 [1]    
Initial Cost to Company [Abstract]      
Land 975,000    
Buildings & Improvements 5,542,000    
Costs capitalized subsequent to acquisition 2,886,000    
Gross amount at which carried at close of period [Abstract]      
Land 980,000    
Buildings & Improvements 8,423,000    
Total 9,403,000    
Accumulated Depreciation (1,711,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | 7800 West Brown Deer Road - Milwaukee, WI [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 10,709,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,455,000    
Buildings & Improvements 8,756,000    
Costs capitalized subsequent to acquisition 2,333,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,475,000    
Buildings & Improvements 11,069,000    
Total 12,544,000    
Accumulated Depreciation (3,233,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | American Corporate Center - Mendota Heights, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,909,000 [1]    
Initial Cost to Company [Abstract]      
Land 893,000    
Buildings & Improvements 16,768,000    
Costs capitalized subsequent to acquisition 3,908,000    
Gross amount at which carried at close of period [Abstract]      
Land 893,000    
Buildings & Improvements 20,676,000    
Total 21,569,000    
Accumulated Depreciation (7,763,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Ameritrade - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,831,000 [1]    
Initial Cost to Company [Abstract]      
Land 327,000    
Buildings & Improvements 7,957,000    
Costs capitalized subsequent to acquisition 65,000    
Gross amount at which carried at close of period [Abstract]      
Land 327,000    
Buildings & Improvements 8,022,000    
Total 8,349,000    
Accumulated Depreciation (2,813,000)    
Year of Construction or Acquisition 1999    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Benton Business Park - Sauk Rapids, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 560,000 [1]    
Initial Cost to Company [Abstract]      
Land 188,000    
Buildings & Improvements 1,261,000    
Costs capitalized subsequent to acquisition 86,000    
Gross amount at which carried at close of period [Abstract]      
Land 188,000    
Buildings & Improvements 1,347,000    
Total 1,535,000    
Accumulated Depreciation (359,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Bismarck 715 East Broadway - Bismarck, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,218,000 [1]    
Initial Cost to Company [Abstract]      
Land 389,000    
Buildings & Improvements 1,283,000    
Costs capitalized subsequent to acquisition 1,126,000    
Gross amount at which carried at close of period [Abstract]      
Land 443,000    
Buildings & Improvements 2,355,000    
Total 2,798,000    
Accumulated Depreciation (287,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Bloomington Business Plaza - Bloomington, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 1,300,000    
Buildings & Improvements 6,106,000    
Costs capitalized subsequent to acquisition 1,625,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,313,000    
Buildings & Improvements 7,718,000    
Total 9,031,000    
Accumulated Depreciation (2,357,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Brenwood - Minnetonka, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,250,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,641,000    
Buildings & Improvements 12,138,000    
Costs capitalized subsequent to acquisition 3,547,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,650,000    
Buildings & Improvements 15,676,000    
Total 17,326,000    
Accumulated Depreciation (4,964,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Brook Valley I - La Vista, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,301,000 [1]    
Initial Cost to Company [Abstract]      
Land 347,000    
Buildings & Improvements 1,671,000    
Costs capitalized subsequent to acquisition 81,000    
Gross amount at which carried at close of period [Abstract]      
Land 347,000    
Buildings & Improvements 1,752,000    
Total 2,099,000    
Accumulated Depreciation (355,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Burnsville Bluffs II - Burnsville, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,719,000 [1]    
Initial Cost to Company [Abstract]      
Land 300,000    
Buildings & Improvements 2,154,000    
Costs capitalized subsequent to acquisition 976,000    
Gross amount at which carried at close of period [Abstract]      
Land 374,000    
Buildings & Improvements 3,056,000    
Total 3,430,000    
Accumulated Depreciation (1,236,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Cold Spring Center - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,661,000 [1]    
Initial Cost to Company [Abstract]      
Land 588,000    
Buildings & Improvements 7,808,000    
Costs capitalized subsequent to acquisition 1,092,000    
Gross amount at which carried at close of period [Abstract]      
Land 727,000    
Buildings & Improvements 8,761,000    
Total 9,488,000    
Accumulated Depreciation (2,913,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Corporate Center West - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 17,315,000 [1]    
Initial Cost to Company [Abstract]      
Land 3,880,000    
Buildings & Improvements 17,509,000    
Costs capitalized subsequent to acquisition 957,000    
Gross amount at which carried at close of period [Abstract]      
Land 4,167,000    
Buildings & Improvements 18,179,000    
Total 22,346,000    
Accumulated Depreciation (2,975,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Crosstown Centre - Eden Prairie, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 13,211,000 [1]    
Initial Cost to Company [Abstract]      
Land 2,884,000    
Buildings & Improvements 14,569,000    
Costs capitalized subsequent to acquisition 2,473,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,919,000    
Buildings & Improvements 17,007,000    
Total 19,926,000    
Accumulated Depreciation (3,660,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Dewey Hill Business Center - Edina, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 985,000    
Buildings & Improvements 3,507,000    
Costs capitalized subsequent to acquisition 904,000    
Gross amount at which carried at close of period [Abstract]      
Land 995,000    
Buildings & Improvements 4,401,000    
Total 5,396,000    
Accumulated Depreciation (1,643,000)    
Year of Construction or Acquisition 2000    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Farnam Executive Center - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 12,160,000 [1]    
Initial Cost to Company [Abstract]      
Land 2,188,000    
Buildings & Improvements 11,404,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 2,188,000    
Buildings & Improvements 11,404,000    
Total 13,592,000    
Accumulated Depreciation (1,889,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Flagship - Eden Prairie, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 21,565,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,899,000    
Buildings & Improvements 21,638,000    
Costs capitalized subsequent to acquisition 1,424,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,094,000    
Buildings & Improvements 22,867,000    
Total 24,961,000    
Accumulated Depreciation (4,125,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Gateway Corporate Center - Woodbury, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,700,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,637,000    
Buildings & Improvements 7,763,000    
Costs capitalized subsequent to acquisition 1,065,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,675,000    
Buildings & Improvements 8,790,000    
Total 10,465,000    
Accumulated Depreciation (1,453,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Golden Hills Office Center - Golden Valley, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 17,988,000 [1]    
Initial Cost to Company [Abstract]      
Land 3,018,000    
Buildings & Improvements 18,544,000    
Costs capitalized subsequent to acquisition 3,639,000    
Gross amount at which carried at close of period [Abstract]      
Land 3,018,000    
Buildings & Improvements 22,183,000    
Total 25,201,000    
Accumulated Depreciation (7,236,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Great Plains - Fargo, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 126,000    
Buildings & Improvements 15,240,000    
Costs capitalized subsequent to acquisition 111,000    
Gross amount at which carried at close of period [Abstract]      
Land 126,000    
Buildings & Improvements 15,351,000    
Total 15,477,000    
Accumulated Depreciation (5,232,000)    
Year of Construction or Acquisition 1997    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Highlands Ranch I - Highlands Ranch, CO [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,221,000 [1]    
Initial Cost to Company [Abstract]      
Land 2,268,000    
Buildings & Improvements 8,362,000    
Costs capitalized subsequent to acquisition 427,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,268,000    
Buildings & Improvements 8,789,000    
Total 11,057,000    
Accumulated Depreciation (1,549,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Highlands Ranch II - Highlands Ranch, CO [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 7,898,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,437,000    
Buildings & Improvements 9,549,000    
Costs capitalized subsequent to acquisition 1,527,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,437,000    
Buildings & Improvements 11,076,000    
Total 12,513,000    
Accumulated Depreciation (2,659,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Interlachen Corporate Center - Edina, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,857,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,650,000    
Buildings & Improvements 14,983,000    
Costs capitalized subsequent to acquisition 2,395,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,668,000    
Buildings & Improvements 17,360,000    
Total 19,028,000    
Accumulated Depreciation (4,990,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Intertech Building - Fenton, MO [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,418,000 [1]    
Initial Cost to Company [Abstract]      
Land 2,130,000    
Buildings & Improvements 3,968,000    
Costs capitalized subsequent to acquisition 1,275,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,165,000    
Buildings & Improvements 5,208,000    
Total 7,373,000    
Accumulated Depreciation (696,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Mendota Office Center I - Mendota Heights, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,836,000 [1]    
Initial Cost to Company [Abstract]      
Land 835,000    
Buildings & Improvements 6,169,000    
Costs capitalized subsequent to acquisition 853,000    
Gross amount at which carried at close of period [Abstract]      
Land 835,000    
Buildings & Improvements 7,022,000    
Total 7,857,000    
Accumulated Depreciation (2,161,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Mendota Office Center II - Mendota Heights, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,668,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,121,000    
Buildings & Improvements 10,085,000    
Costs capitalized subsequent to acquisition 1,501,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,121,000    
Buildings & Improvements 11,586,000    
Total 12,707,000    
Accumulated Depreciation (4,185,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Mendota Office Center III - Mendota Heights, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,895,000 [1]    
Initial Cost to Company [Abstract]      
Land 970,000    
Buildings & Improvements 5,734,000    
Costs capitalized subsequent to acquisition 697,000    
Gross amount at which carried at close of period [Abstract]      
Land 970,000    
Buildings & Improvements 6,431,000    
Total 7,401,000    
Accumulated Depreciation (1,888,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Mendota Office Center IV - Mendota Heights, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,631,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,070,000    
Buildings & Improvements 7,635,000    
Costs capitalized subsequent to acquisition 578,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,070,000    
Buildings & Improvements 8,213,000    
Total 9,283,000    
Accumulated Depreciation (2,716,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Minnesota National Bank - Duluth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 781,000 [1]    
Initial Cost to Company [Abstract]      
Land 287,000    
Buildings & Improvements 1,454,000    
Costs capitalized subsequent to acquisition 174,000    
Gross amount at which carried at close of period [Abstract]      
Land 288,000    
Buildings & Improvements 1,627,000    
Total 1,915,000    
Accumulated Depreciation (352,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Minot 2505 16th Street SW - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 298,000 [5]    
Buildings & Improvements 1,724,000 [5]    
Costs capitalized subsequent to acquisition 296,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 298,000 [5]    
Buildings & Improvements 2,020,000 [5]    
Total 2,318,000 [5]    
Accumulated Depreciation (164,000) [5]    
Year of Construction or Acquisition 2009 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Office [Member] | Miracle Hills One - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,895,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,974,000    
Buildings & Improvements 10,117,000    
Costs capitalized subsequent to acquisition 1,450,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,120,000    
Buildings & Improvements 11,421,000    
Total 13,541,000    
Accumulated Depreciation (2,446,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Nicollett VII - Burnsville, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 429,000    
Buildings & Improvements 6,931,000    
Costs capitalized subsequent to acquisition 410,000    
Gross amount at which carried at close of period [Abstract]      
Land 436,000    
Buildings & Improvements 7,334,000    
Total 7,770,000    
Accumulated Depreciation (2,181,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Northgate I - Maple Grove, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,163,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,062,000    
Buildings & Improvements 6,358,000    
Costs capitalized subsequent to acquisition 990,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,235,000    
Buildings & Improvements 7,175,000    
Total 8,410,000    
Accumulated Depreciation (1,637,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Northgate II - Maple Grove, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 939,000 [1]    
Initial Cost to Company [Abstract]      
Land 359,000    
Buildings & Improvements 1,944,000    
Costs capitalized subsequent to acquisition 284,000    
Gross amount at which carried at close of period [Abstract]      
Land 403,000    
Buildings & Improvements 2,184,000    
Total 2,587,000    
Accumulated Depreciation (744,000)    
Year of Construction or Acquisition 1999    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Northpark Corporate Center - Arden Hills, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 12,332,000 [1]    
Initial Cost to Company [Abstract]      
Land 2,034,000    
Buildings & Improvements 14,584,000    
Costs capitalized subsequent to acquisition 1,585,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,034,000    
Buildings & Improvements 16,169,000    
Total 18,203,000    
Accumulated Depreciation (3,104,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Omaha 10802 Farnam Dr - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,297,000 [1]    
Initial Cost to Company [Abstract]      
Land 2,462,000    
Buildings & Improvements 4,374,000    
Costs capitalized subsequent to acquisition 392,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,818,000    
Buildings & Improvements 4,410,000    
Total 7,228,000    
Accumulated Depreciation (269,000)    
Year of Construction or Acquisition 2010    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Pacific Hills - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 16,770,000 [1]    
Initial Cost to Company [Abstract]      
Land 4,220,000    
Buildings & Improvements 11,988,000    
Costs capitalized subsequent to acquisition 2,179,000    
Gross amount at which carried at close of period [Abstract]      
Land 4,507,000    
Buildings & Improvements 13,880,000    
Total 18,387,000    
Accumulated Depreciation (2,604,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Pillsbury Business Center - Bloomington, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 284,000    
Buildings & Improvements 1,556,000    
Costs capitalized subsequent to acquisition 171,000    
Gross amount at which carried at close of period [Abstract]      
Land 299,000    
Buildings & Improvements 1,712,000    
Total 2,011,000    
Accumulated Depreciation (551,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Plaza 16 - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 7,434,000 [1]    
Initial Cost to Company [Abstract]      
Land 389,000    
Buildings & Improvements 5,444,000    
Costs capitalized subsequent to acquisition 3,843,000    
Gross amount at which carried at close of period [Abstract]      
Land 591,000    
Buildings & Improvements 9,085,000    
Total 9,676,000    
Accumulated Depreciation (1,291,000)    
Year of Construction or Acquisition 2009    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Plaza VII - Boise, ID [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 993,000 [1]    
Initial Cost to Company [Abstract]      
Land 300,000    
Buildings & Improvements 3,058,000    
Costs capitalized subsequent to acquisition 478,000    
Gross amount at which carried at close of period [Abstract]      
Land 351,000    
Buildings & Improvements 3,485,000    
Total 3,836,000    
Accumulated Depreciation (1,027,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Plymouth 5095 Nathan Lane - Plymouth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,215,000 [1]    
Initial Cost to Company [Abstract]      
Land 604,000    
Buildings & Improvements 1,253,000    
Costs capitalized subsequent to acquisition 83,000    
Gross amount at which carried at close of period [Abstract]      
Land 636,000    
Buildings & Improvements 1,304,000    
Total 1,940,000    
Accumulated Depreciation (190,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Plymouth I - Plymouth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,157,000 [1]    
Initial Cost to Company [Abstract]      
Land 530,000    
Buildings & Improvements 1,133,000    
Costs capitalized subsequent to acquisition 65,000    
Gross amount at which carried at close of period [Abstract]      
Land 530,000    
Buildings & Improvements 1,198,000    
Total 1,728,000    
Accumulated Depreciation (274,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Plymouth II - Plymouth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,157,000 [1]    
Initial Cost to Company [Abstract]      
Land 367,000    
Buildings & Improvements 1,264,000    
Costs capitalized subsequent to acquisition 40,000    
Gross amount at which carried at close of period [Abstract]      
Land 367,000    
Buildings & Improvements 1,304,000    
Total 1,671,000    
Accumulated Depreciation (305,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Plymouth III - Plymouth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,425,000 [1]    
Initial Cost to Company [Abstract]      
Land 507,000    
Buildings & Improvements 1,495,000    
Costs capitalized subsequent to acquisition 365,000    
Gross amount at which carried at close of period [Abstract]      
Land 507,000    
Buildings & Improvements 1,860,000    
Total 2,367,000    
Accumulated Depreciation (490,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Plymouth IV & V - Plymouth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 6,875,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,336,000    
Buildings & Improvements 12,693,000    
Costs capitalized subsequent to acquisition 2,141,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,338,000    
Buildings & Improvements 14,832,000    
Total 16,170,000    
Accumulated Depreciation (4,771,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Prairie Oak Business Center - Eden Prairie, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,304,000 [1]    
Initial Cost to Company [Abstract]      
Land 531,000    
Buildings & Improvements 4,069,000    
Costs capitalized subsequent to acquisition 1,852,000    
Gross amount at which carried at close of period [Abstract]      
Land 764,000    
Buildings & Improvements 5,688,000    
Total 6,452,000    
Accumulated Depreciation (1,904,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Rapid City 900 Concourse Drive - Rapid City, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,171,000 [1]    
Initial Cost to Company [Abstract]      
Land 285,000    
Buildings & Improvements 6,600,000    
Costs capitalized subsequent to acquisition 736,000    
Gross amount at which carried at close of period [Abstract]      
Land 514,000    
Buildings & Improvements 7,107,000    
Total 7,621,000    
Accumulated Depreciation (2,275,000)    
Year of Construction or Acquisition 2000    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Riverport - Maryland Heights, MO [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 19,690,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,891,000    
Buildings & Improvements 18,982,000    
Costs capitalized subsequent to acquisition 554,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,917,000    
Buildings & Improvements 19,510,000    
Total 21,427,000    
Accumulated Depreciation (3,285,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Southeast Tech Center - Eagan, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,691,000 [1]    
Initial Cost to Company [Abstract]      
Land 560,000    
Buildings & Improvements 5,496,000    
Costs capitalized subsequent to acquisition 419,000    
Gross amount at which carried at close of period [Abstract]      
Land 569,000    
Buildings & Improvements 5,906,000    
Total 6,475,000    
Accumulated Depreciation (2,133,000)    
Year of Construction or Acquisition 1999    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Spring Valley IV - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 775,000 [1]    
Initial Cost to Company [Abstract]      
Land 178,000    
Buildings & Improvements 916,000    
Costs capitalized subsequent to acquisition 60,000    
Gross amount at which carried at close of period [Abstract]      
Land 186,000    
Buildings & Improvements 968,000    
Total 1,154,000    
Accumulated Depreciation (212,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Spring Valley V - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 852,000 [1]    
Initial Cost to Company [Abstract]      
Land 212,000    
Buildings & Improvements 1,123,000    
Costs capitalized subsequent to acquisition 251,000    
Gross amount at which carried at close of period [Abstract]      
Land 240,000    
Buildings & Improvements 1,346,000    
Total 1,586,000    
Accumulated Depreciation (295,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Spring Valley X - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 790,000 [1]    
Initial Cost to Company [Abstract]      
Land 180,000    
Buildings & Improvements 1,024,000    
Costs capitalized subsequent to acquisition 60,000    
Gross amount at which carried at close of period [Abstract]      
Land 189,000    
Buildings & Improvements 1,075,000    
Total 1,264,000    
Accumulated Depreciation (212,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Spring Valley XI - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 775,000 [1]    
Initial Cost to Company [Abstract]      
Land 143,000    
Buildings & Improvements 1,094,000    
Costs capitalized subsequent to acquisition 36,000    
Gross amount at which carried at close of period [Abstract]      
Land 151,000    
Buildings & Improvements 1,122,000    
Total 1,273,000    
Accumulated Depreciation (218,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Superior Office Building - Duluth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,174,000 [1]    
Initial Cost to Company [Abstract]      
Land 336,000    
Buildings & Improvements 2,200,000    
Costs capitalized subsequent to acquisition 83,000    
Gross amount at which carried at close of period [Abstract]      
Land 336,000    
Buildings & Improvements 2,283,000    
Total 2,619,000    
Accumulated Depreciation (526,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | TCA Building - Eagan, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 7,080,000 [1]    
Initial Cost to Company [Abstract]      
Land 627,000    
Buildings & Improvements 8,571,000    
Costs capitalized subsequent to acquisition 911,000    
Gross amount at which carried at close of period [Abstract]      
Land 684,000    
Buildings & Improvements 9,425,000    
Total 10,109,000    
Accumulated Depreciation (2,616,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Three Paramount Plaza - Bloomington, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 1,261,000 [5]    
Buildings & Improvements 6,149,000 [5]    
Costs capitalized subsequent to acquisition 1,755,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 1,298,000 [5]    
Buildings & Improvements 7,867,000 [5]    
Total 9,165,000 [5]    
Accumulated Depreciation (2,539,000) [5]    
Year of Construction or Acquisition 2002 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Office [Member] | Thresher Square - Minneapolis, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 1,094,000    
Buildings & Improvements 10,026,000    
Costs capitalized subsequent to acquisition 1,643,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,104,000    
Buildings & Improvements 11,659,000    
Total 12,763,000    
Accumulated Depreciation (3,648,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Timberlands - Leawood, KS [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 13,155,000 [1]    
Initial Cost to Company [Abstract]      
Land 2,375,000    
Buildings & Improvements 12,218,000    
Costs capitalized subsequent to acquisition 1,405,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,495,000    
Buildings & Improvements 13,503,000    
Total 15,998,000    
Accumulated Depreciation (2,603,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | UHC Office - International Falls, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 995,000 [1]    
Initial Cost to Company [Abstract]      
Land 119,000    
Buildings & Improvements 2,366,000    
Costs capitalized subsequent to acquisition 80,000    
Gross amount at which carried at close of period [Abstract]      
Land 119,000    
Buildings & Improvements 2,446,000    
Total 2,565,000    
Accumulated Depreciation (586,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | US Bank Financial Center - Bloomington, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 13,425,000 [1]    
Initial Cost to Company [Abstract]      
Land 3,117,000    
Buildings & Improvements 13,350,000    
Costs capitalized subsequent to acquisition 610,000    
Gross amount at which carried at close of period [Abstract]      
Land 3,119,000    
Buildings & Improvements 13,958,000    
Total 17,077,000    
Accumulated Depreciation (2,894,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Viromed - Eden Prairie, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 324,000 [1]    
Initial Cost to Company [Abstract]      
Land 666,000    
Buildings & Improvements 4,197,000    
Costs capitalized subsequent to acquisition 1,000    
Gross amount at which carried at close of period [Abstract]      
Land 666,000    
Buildings & Improvements 4,198,000    
Total 4,864,000    
Accumulated Depreciation (1,491,000)    
Year of Construction or Acquisition 1999    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Wells Fargo Center - St Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 6,206,000 [1]    
Initial Cost to Company [Abstract]      
Land 869,000    
Buildings & Improvements 8,373,000    
Costs capitalized subsequent to acquisition 1,448,000    
Gross amount at which carried at close of period [Abstract]      
Land 869,000    
Buildings & Improvements 9,821,000    
Total 10,690,000    
Accumulated Depreciation (2,087,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | West River Business Park - Waite Park, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 560,000 [1]    
Initial Cost to Company [Abstract]      
Land 235,000    
Buildings & Improvements 1,195,000    
Costs capitalized subsequent to acquisition 50,000    
Gross amount at which carried at close of period [Abstract]      
Land 235,000    
Buildings & Improvements 1,245,000    
Total 1,480,000    
Accumulated Depreciation (322,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Westgate - Boise, ID [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,125,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,000,000    
Buildings & Improvements 10,618,000    
Costs capitalized subsequent to acquisition 1,921,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,000,000    
Buildings & Improvements 12,539,000    
Total 13,539,000    
Accumulated Depreciation (3,573,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Whitewater Plaza - Minnetonka, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,830,000 [1]    
Initial Cost to Company [Abstract]      
Land 530,000    
Buildings & Improvements 4,860,000    
Costs capitalized subsequent to acquisition 850,000    
Gross amount at which carried at close of period [Abstract]      
Land 577,000    
Buildings & Improvements 5,663,000    
Total 6,240,000    
Accumulated Depreciation (1,774,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Wirth Corporate Center - Golden Valley, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,539,000 [1]    
Initial Cost to Company [Abstract]      
Land 970,000    
Buildings & Improvements 7,659,000    
Costs capitalized subsequent to acquisition 911,000    
Gross amount at which carried at close of period [Abstract]      
Land 971,000    
Buildings & Improvements 8,569,000    
Total 9,540,000    
Accumulated Depreciation (2,568,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Office [Member] | Woodlands Plaza IV - Maryland Heights, MO [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,360,000 [1]    
Initial Cost to Company [Abstract]      
Land 771,000    
Buildings & Improvements 4,609,000    
Costs capitalized subsequent to acquisition 1,441,000    
Gross amount at which carried at close of period [Abstract]      
Land 837,000    
Buildings & Improvements 5,984,000    
Total 6,821,000    
Accumulated Depreciation (1,033,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 255,386,000 [1]    
Initial Cost to Company [Abstract]      
Land 32,386,000    
Buildings & Improvements 423,642,000    
Costs capitalized subsequent to acquisition 45,163,000    
Gross amount at which carried at close of period [Abstract]      
Land 32,847,000    
Buildings & Improvements 468,344,000    
Total 501,191,000    
Accumulated Depreciation (90,891,000)    
Additions during year [Abstract]      
Additions 11,122,000 47,408,000 19,249,000
Commercial-Healthcare [Member] | 2800 Medical Building - Minneapolis, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,399,000 [1]    
Initial Cost to Company [Abstract]      
Land 204,000    
Buildings & Improvements 7,135,000    
Costs capitalized subsequent to acquisition 2,191,000    
Gross amount at which carried at close of period [Abstract]      
Land 229,000    
Buildings & Improvements 9,301,000    
Total 9,530,000    
Accumulated Depreciation (2,343,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | 2828 Chicago Avenue - Minneapolis, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,379,000 [1]    
Initial Cost to Company [Abstract]      
Land 726,000    
Buildings & Improvements 11,319,000    
Costs capitalized subsequent to acquisition 5,627,000    
Gross amount at which carried at close of period [Abstract]      
Land 729,000    
Buildings & Improvements 16,943,000    
Total 17,672,000    
Accumulated Depreciation (2,764,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Airport Medical - Bloomington, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,083,000 [1]    
Initial Cost to Company [Abstract]      
Land 0    
Buildings & Improvements 4,678,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 0    
Buildings & Improvements 4,678,000    
Total 4,678,000    
Accumulated Depreciation (1,497,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Barry Pointe Office Park - Kansas City, MO [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,435,000 [1]    
Initial Cost to Company [Abstract]      
Land 384,000    
Buildings & Improvements 2,366,000    
Costs capitalized subsequent to acquisition 103,000    
Gross amount at which carried at close of period [Abstract]      
Land 392,000    
Buildings & Improvements 2,461,000    
Total 2,853,000    
Accumulated Depreciation (398,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Billings 2300 Grant Road - Billings, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,645,000 [1]    
Initial Cost to Company [Abstract]      
Land 649,000    
Buildings & Improvements 1,216,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 649,000    
Buildings & Improvements 1,216,000    
Total 1,865,000    
Accumulated Depreciation (85,000)    
Year of Construction or Acquisition 2010    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Burnsville 303 Nicollet Medical (Ridgeview) - Burnsville, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,445,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,071,000    
Buildings & Improvements 6,842,000    
Costs capitalized subsequent to acquisition 1,523,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,071,000    
Buildings & Improvements 8,365,000    
Total 9,436,000    
Accumulated Depreciation (1,054,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Burnsville 305 Nicollet Medical (Ridgeview South) - Burnsville, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,287,000 [1]    
Initial Cost to Company [Abstract]      
Land 189,000    
Buildings & Improvements 5,127,000    
Costs capitalized subsequent to acquisition 768,000    
Gross amount at which carried at close of period [Abstract]      
Land 189,000    
Buildings & Improvements 5,895,000    
Total 6,084,000    
Accumulated Depreciation (741,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Casper 1930 E 12th Street (Park Place) - Casper, WY [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 439,000 [5]    
Buildings & Improvements 5,780,000 [5]    
Costs capitalized subsequent to acquisition 162,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 439,000 [5]    
Buildings & Improvements 5,942,000 [5]    
Total 6,381,000 [5]    
Accumulated Depreciation (530,000) [5]    
Year of Construction or Acquisition 2009 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Healthcare [Member] | Casper 3955 E 12th Street (Meadow Wind) - Casper, WY [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 388,000 [5]    
Buildings & Improvements 10,494,000 [5]    
Costs capitalized subsequent to acquisition 25,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 388,000 [5]    
Buildings & Improvements 10,519,000 [5]    
Total 10,907,000 [5]    
Accumulated Depreciation (775,000) [5]    
Year of Construction or Acquisition 2009 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Healthcare [Member] | Cheyenne 4010 N College Drive (Aspen Wind) - Cheyenne, WY [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 628,000 [5]    
Buildings & Improvements 10,272,000 [5]    
Costs capitalized subsequent to acquisition 260,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 629,000 [5]    
Buildings & Improvements 10,531,000 [5]    
Total 11,160,000 [5]    
Accumulated Depreciation (903,000) [5]    
Year of Construction or Acquisition 2009 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Healthcare [Member] | Cheyenne 4606 N College Drive (Sierra Hills) - Cheyenne, WY [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 695,000 [5]    
Buildings & Improvements 7,455,000 [5]    
Costs capitalized subsequent to acquisition 40,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 695,000 [5]    
Buildings & Improvements 7,495,000 [5]    
Total 8,190,000 [5]    
Accumulated Depreciation (639,000) [5]    
Year of Construction or Acquisition 2009 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Healthcare [Member] | Denfeld Clinic - Duluth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,656,000 [1]    
Initial Cost to Company [Abstract]      
Land 501,000    
Buildings & Improvements 2,597,000    
Costs capitalized subsequent to acquisition 1,000    
Gross amount at which carried at close of period [Abstract]      
Land 501,000    
Buildings & Improvements 2,598,000    
Total 3,099,000    
Accumulated Depreciation (588,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Eagan 1440 Duckwood Medical - Eagan, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,811,000 [1]    
Initial Cost to Company [Abstract]      
Land 521,000    
Buildings & Improvements 1,547,000    
Costs capitalized subsequent to acquisition 519,000    
Gross amount at which carried at close of period [Abstract]      
Land 521,000    
Buildings & Improvements 2,066,000    
Total 2,587,000    
Accumulated Depreciation (447,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Belgrade, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 35,000    
Buildings & Improvements 779,000    
Costs capitalized subsequent to acquisition 5,000    
Gross amount at which carried at close of period [Abstract]      
Land 35,000    
Buildings & Improvements 784,000    
Total 819,000    
Accumulated Depreciation (100,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Billings, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,905,000 [1]    
Initial Cost to Company [Abstract]      
Land 115,000    
Buildings & Improvements 1,767,000    
Costs capitalized subsequent to acquisition 7,000    
Gross amount at which carried at close of period [Abstract]      
Land 115,000    
Buildings & Improvements 1,774,000    
Total 1,889,000    
Accumulated Depreciation (231,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Bismarck, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 511,000    
Buildings & Improvements 9,193,000    
Costs capitalized subsequent to acquisition 114,000    
Gross amount at which carried at close of period [Abstract]      
Land 511,000    
Buildings & Improvements 9,307,000    
Total 9,818,000    
Accumulated Depreciation (1,758,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Brainerd, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 587,000    
Buildings & Improvements 8,999,000    
Costs capitalized subsequent to acquisition 54,000    
Gross amount at which carried at close of period [Abstract]      
Land 587,000    
Buildings & Improvements 9,053,000    
Total 9,640,000    
Accumulated Depreciation (1,721,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Columbus, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 43,000 [5]    
Buildings & Improvements 824,000 [5]    
Costs capitalized subsequent to acquisition 3,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 44,000 [5]    
Buildings & Improvements 826,000 [5]    
Total 870,000 [5]    
Accumulated Depreciation (106,000) [5]    
Year of Construction or Acquisition 2008 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Healthcare [Member] | Edgewood Vista - East Grand Forks, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,902,000 [1]    
Initial Cost to Company [Abstract]      
Land 290,000    
Buildings & Improvements 1,352,000    
Costs capitalized subsequent to acquisition 15,000    
Gross amount at which carried at close of period [Abstract]      
Land 290,000    
Buildings & Improvements 1,367,000    
Total 1,657,000    
Accumulated Depreciation (177,000)    
Year of Construction or Acquisition 2000    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Fargo, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 12,877,000 [1]    
Initial Cost to Company [Abstract]      
Land 775,000    
Buildings & Improvements 20,870,000    
Costs capitalized subsequent to acquisition 9,000    
Gross amount at which carried at close of period [Abstract]      
Land 775,000    
Buildings & Improvements 20,879,000    
Total 21,654,000    
Accumulated Depreciation (2,674,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Fremont, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 593,000 [1]    
Initial Cost to Company [Abstract]      
Land 56,000    
Buildings & Improvements 490,000    
Costs capitalized subsequent to acquisition 42,000    
Gross amount at which carried at close of period [Abstract]      
Land 56,000    
Buildings & Improvements 532,000    
Total 588,000    
Accumulated Depreciation (153,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Grand Island, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 33,000 [5]    
Buildings & Improvements 773,000 [5]    
Costs capitalized subsequent to acquisition 30,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 39,000 [5]    
Buildings & Improvements 797,000 [5]    
Total 836,000 [5]    
Accumulated Depreciation (100,000) [5]    
Year of Construction or Acquisition 2008 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Healthcare [Member] | Edgewood Vista - Hastings, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 611,000 [1]    
Initial Cost to Company [Abstract]      
Land 49,000    
Buildings & Improvements 517,000    
Costs capitalized subsequent to acquisition 44,000    
Gross amount at which carried at close of period [Abstract]      
Land 50,000    
Buildings & Improvements 560,000    
Total 610,000    
Accumulated Depreciation (167,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Hermantown I, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 16,382,000 [1]    
Initial Cost to Company [Abstract]      
Land 288,000    
Buildings & Improvements 9,871,000    
Costs capitalized subsequent to acquisition 1,514,000    
Gross amount at which carried at close of period [Abstract]      
Land 288,000    
Buildings & Improvements 11,385,000    
Total 11,673,000    
Accumulated Depreciation (3,304,000)    
Year of Construction or Acquisition 2000    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Hermantown II, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 719,000    
Buildings & Improvements 10,517,000    
Costs capitalized subsequent to acquisition 33,000    
Gross amount at which carried at close of period [Abstract]      
Land 719,000    
Buildings & Improvements 10,550,000    
Total 11,269,000    
Accumulated Depreciation (2,009,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Kalispell, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 613,000 [1]    
Initial Cost to Company [Abstract]      
Land 70,000    
Buildings & Improvements 502,000    
Costs capitalized subsequent to acquisition 603,000    
Gross amount at which carried at close of period [Abstract]      
Land 70,000    
Buildings & Improvements 1,105,000    
Total 1,175,000    
Accumulated Depreciation (211,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 9,470,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,045,000    
Buildings & Improvements 11,590,000    
Costs capitalized subsequent to acquisition 70,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,047,000    
Buildings & Improvements 11,658,000    
Total 12,705,000    
Accumulated Depreciation (714,000)    
Year of Construction or Acquisition 2010    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Missoula, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 870,000 [1]    
Initial Cost to Company [Abstract]      
Land 109,000    
Buildings & Improvements 854,000    
Costs capitalized subsequent to acquisition 72,000    
Gross amount at which carried at close of period [Abstract]      
Land 116,000    
Buildings & Improvements 919,000    
Total 1,035,000    
Accumulated Depreciation (359,000)    
Year of Construction or Acquisition 1996    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Norfolk, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 42,000 [5]    
Buildings & Improvements 722,000 [5]    
Costs capitalized subsequent to acquisition 7,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 42,000 [5]    
Buildings & Improvements 729,000 [5]    
Total 771,000 [5]    
Accumulated Depreciation (93,000) [5]    
Year of Construction or Acquisition 2008 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Healthcare [Member] | Edgewood Vista - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 387,000 [1]    
Initial Cost to Company [Abstract]      
Land 89,000    
Buildings & Improvements 547,000    
Costs capitalized subsequent to acquisition 42,000    
Gross amount at which carried at close of period [Abstract]      
Land 89,000    
Buildings & Improvements 589,000    
Total 678,000    
Accumulated Depreciation (171,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Sioux Falls, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,091,000 [1]    
Initial Cost to Company [Abstract]      
Land 314,000    
Buildings & Improvements 974,000    
Costs capitalized subsequent to acquisition 12,000    
Gross amount at which carried at close of period [Abstract]      
Land 314,000    
Buildings & Improvements 986,000    
Total 1,300,000    
Accumulated Depreciation (128,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Spearfish, SD [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 315,000    
Buildings & Improvements 8,584,000    
Costs capitalized subsequent to acquisition 65,000    
Gross amount at which carried at close of period [Abstract]      
Land 330,000    
Buildings & Improvements 8,634,000    
Total 8,964,000    
Accumulated Depreciation (1,271,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edgewood Vista - Virginia, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 13,932,000 [1]    
Initial Cost to Company [Abstract]      
Land 246,000    
Buildings & Improvements 11,823,000    
Costs capitalized subsequent to acquisition 115,000    
Gross amount at which carried at close of period [Abstract]      
Land 246,000    
Buildings & Improvements 11,938,000    
Total 12,184,000    
Accumulated Depreciation (3,056,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edina 6363 France Medical - Edina, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 10,000,000 [1]    
Initial Cost to Company [Abstract]      
Land 0    
Buildings & Improvements 12,675,000    
Costs capitalized subsequent to acquisition 1,762,000    
Gross amount at which carried at close of period [Abstract]      
Land 0    
Buildings & Improvements 14,437,000    
Total 14,437,000    
Accumulated Depreciation (2,458,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edina 6405 France Medical - Edina, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 8,782,000 [1]    
Initial Cost to Company [Abstract]      
Land 0    
Buildings & Improvements 12,201,000    
Costs capitalized subsequent to acquisition 41,000    
Gross amount at which carried at close of period [Abstract]      
Land 0    
Buildings & Improvements 12,242,000    
Total 12,242,000    
Accumulated Depreciation (2,097,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edina 6517 Drew Avenue - Edina, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,133,000 [1]    
Initial Cost to Company [Abstract]      
Land 353,000    
Buildings & Improvements 660,000    
Costs capitalized subsequent to acquisition 529,000    
Gross amount at which carried at close of period [Abstract]      
Land 372,000    
Buildings & Improvements 1,170,000    
Total 1,542,000    
Accumulated Depreciation (460,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edina 6525 Drew Avenue - Edina, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 388,000    
Buildings & Improvements 117,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 388,000    
Buildings & Improvements 117,000    
Total 505,000    
Accumulated Depreciation (4,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edina 6525 France SMC II - Edina, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 10,170,000 [1]    
Initial Cost to Company [Abstract]      
Land 755,000    
Buildings & Improvements 8,054,000    
Costs capitalized subsequent to acquisition 6,018,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,040,000    
Buildings & Improvements 13,787,000    
Total 14,827,000    
Accumulated Depreciation (5,226,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Edina 6545 France SMC I - Edina MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 30,786,000 [1]    
Initial Cost to Company [Abstract]      
Land 3,480,000    
Buildings & Improvements 30,743,000    
Costs capitalized subsequent to acquisition 12,464,000    
Gross amount at which carried at close of period [Abstract]      
Land 3,480,000    
Buildings & Improvements 43,207,000    
Total 46,687,000    
Accumulated Depreciation (14,411,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Fresenius - Duluth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 716,000 [1]    
Initial Cost to Company [Abstract]      
Land 50,000    
Buildings & Improvements 1,520,000    
Costs capitalized subsequent to acquisition 2,000    
Gross amount at which carried at close of period [Abstract]      
Land 50,000    
Buildings & Improvements 1,522,000    
Total 1,572,000    
Accumulated Depreciation (344,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Garden View - St. Paul, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,320,000 [1]    
Initial Cost to Company [Abstract]      
Land 0    
Buildings & Improvements 7,408,000    
Costs capitalized subsequent to acquisition 709,000    
Gross amount at which carried at close of period [Abstract]      
Land 12,000    
Buildings & Improvements 8,105,000    
Total 8,117,000    
Accumulated Depreciation (2,217,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Gateway Clinic - Sandstone, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 959,000 [1]    
Initial Cost to Company [Abstract]      
Land 66,000    
Buildings & Improvements 1,699,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 66,000    
Buildings & Improvements 1,699,000    
Total 1,765,000    
Accumulated Depreciation (384,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Healtheast St John & Woodwinds - Maplewood & Woodbury, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 10,304,000 [1]    
Initial Cost to Company [Abstract]      
Land 3,239,000    
Buildings & Improvements 18,362,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 3,239,000    
Buildings & Improvements 18,362,000    
Total 21,601,000    
Accumulated Depreciation (5,948,000)    
Year of Construction or Acquisition 2000    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | High Pointe Health Campus - Lake Elmo, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,400,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,305,000    
Buildings & Improvements 10,528,000    
Costs capitalized subsequent to acquisition 1,630,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,329,000    
Buildings & Improvements 12,134,000    
Total 13,463,000    
Accumulated Depreciation (2,888,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Jamestown Medical Office Building - Jamestown, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 6,200,000 [1]    
Initial Cost to Company [Abstract]      
Land 0    
Buildings & Improvements 7,605,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 0    
Buildings & Improvements 7,605,000    
Total 7,605,000    
Accumulated Depreciation (76,000)    
Year of Construction or Acquisition 2013    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Laramie 1072 N 22nd Street (Spring Wind) - Laramie, WY [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 406,000 [5]    
Buildings & Improvements 10,151,000 [5]    
Costs capitalized subsequent to acquisition 17,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 406,000 [5]    
Buildings & Improvements 10,168,000 [5]    
Total 10,574,000 [5]    
Accumulated Depreciation (631,000) [5]    
Year of Construction or Acquisition 2009 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Healthcare [Member] | Mariner Clinic - Superior, WI [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,097,000 [1]    
Initial Cost to Company [Abstract]      
Land 0    
Buildings & Improvements 3,781,000    
Costs capitalized subsequent to acquisition 90,000    
Gross amount at which carried at close of period [Abstract]      
Land 20,000    
Buildings & Improvements 3,851,000    
Total 3,871,000    
Accumulated Depreciation (871,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Minneapolis 701 25th Avenue Medical - Minneapolis, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 7,532,000 [1]    
Initial Cost to Company [Abstract]      
Land 0    
Buildings & Improvements 7,873,000    
Costs capitalized subsequent to acquisition 1,093,000    
Gross amount at which carried at close of period [Abstract]      
Land 0    
Buildings & Improvements 8,966,000    
Total 8,966,000    
Accumulated Depreciation (1,133,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Missoula 3050 Great Northern - Missoula, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,727,000 [1]    
Initial Cost to Company [Abstract]      
Land 640,000    
Buildings & Improvements 1,331,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 640,000    
Buildings & Improvements 1,331,000    
Total 1,971,000    
Accumulated Depreciation (93,000)    
Year of Construction or Acquisition 2010    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Nebraska Orthopedic Hospital - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 11,964,000 [1]    
Initial Cost to Company [Abstract]      
Land 0    
Buildings & Improvements 20,272,000    
Costs capitalized subsequent to acquisition 1,615,000    
Gross amount at which carried at close of period [Abstract]      
Land 0    
Buildings & Improvements 21,887,000    
Total 21,887,000    
Accumulated Depreciation (4,764,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Park Dental - Brooklyn Center, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 621,000 [1]    
Initial Cost to Company [Abstract]      
Land 185,000    
Buildings & Improvements 2,767,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 185,000    
Buildings & Improvements 2,767,000    
Total 2,952,000    
Accumulated Depreciation (735,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Pavilion I - Duluth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 5,525,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,245,000    
Buildings & Improvements 8,898,000    
Costs capitalized subsequent to acquisition 31,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,245,000    
Buildings & Improvements 8,929,000    
Total 10,174,000    
Accumulated Depreciation (1,993,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Pavilion II - Duluth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 10,168,000 [1]    
Initial Cost to Company [Abstract]      
Land 2,715,000    
Buildings & Improvements 14,673,000    
Costs capitalized subsequent to acquisition 1,937,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,715,000    
Buildings & Improvements 16,610,000    
Total 19,325,000    
Accumulated Depreciation (4,739,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Ritchie Medical Plaza - St Paul, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 6,463,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,615,000    
Buildings & Improvements 7,851,000    
Costs capitalized subsequent to acquisition 1,911,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,647,000    
Buildings & Improvements 9,730,000    
Total 11,377,000    
Accumulated Depreciation (1,952,000)    
Year of Construction or Acquisition 2005    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Sartell 2000 23rd Street South - Sartell, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,256,000 [1]    
Initial Cost to Company [Abstract]      
Land 0    
Buildings & Improvements 11,781,000    
Costs capitalized subsequent to acquisition 935,000    
Gross amount at which carried at close of period [Abstract]      
Land 0    
Buildings & Improvements 12,716,000    
Total 12,716,000    
Accumulated Depreciation (3,458,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Spring Creek American Falls- American Falls, ID [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,328,000 [1]    
Initial Cost to Company [Abstract]      
Land 145,000    
Buildings & Improvements 3,870,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 145,000    
Buildings & Improvements 3,870,000    
Total 4,015,000    
Accumulated Depreciation (180,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Spring Creek-Boise - Boise, ID [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,957,000 [1]    
Initial Cost to Company [Abstract]      
Land 708,000    
Buildings & Improvements 4,296,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 708,000    
Buildings & Improvements 4,296,000    
Total 5,004,000    
Accumulated Depreciation (214,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Spring Creek-Eagle - Eagle, ID [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,141,000 [1]    
Initial Cost to Company [Abstract]      
Land 263,000    
Buildings & Improvements 3,775,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 263,000    
Buildings & Improvements 3,775,000    
Total 4,038,000    
Accumulated Depreciation (176,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Spring Creek-Meridian - Meridian, ID [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,538,000 [1]    
Initial Cost to Company [Abstract]      
Land 424,000    
Buildings & Improvements 6,724,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 424,000    
Buildings & Improvements 6,724,000    
Total 7,148,000    
Accumulated Depreciation (310,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Spring Creek-Overland - Overland, ID [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,339,000 [1]    
Initial Cost to Company [Abstract]      
Land 687,000    
Buildings & Improvements 5,941,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 687,000    
Buildings & Improvements 5,941,000    
Total 6,628,000    
Accumulated Depreciation (286,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Spring Creek-Soda Springs - Soda Springs, ID [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 838,000 [1]    
Initial Cost to Company [Abstract]      
Land 66,000    
Buildings & Improvements 2,134,000    
Costs capitalized subsequent to acquisition 33,000    
Gross amount at which carried at close of period [Abstract]      
Land 66,000    
Buildings & Improvements 2,167,000    
Total 2,233,000    
Accumulated Depreciation (101,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Spring Creek-Ustick - Meridian, ID [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 467,000    
Buildings & Improvements 3,833,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 467,000    
Buildings & Improvements 3,833,000    
Total 4,300,000    
Accumulated Depreciation (165,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | St Michael Clinic - St Michael, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,902,000 [1]    
Initial Cost to Company [Abstract]      
Land 328,000    
Buildings & Improvements 2,259,000    
Costs capitalized subsequent to acquisition 264,000    
Gross amount at which carried at close of period [Abstract]      
Land 328,000    
Buildings & Improvements 2,523,000    
Total 2,851,000    
Accumulated Depreciation (384,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Trinity at Plaza 16 - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,984,000 [1]    
Initial Cost to Company [Abstract]      
Land 568,000    
Buildings & Improvements 8,987,000    
Costs capitalized subsequent to acquisition 5,000    
Gross amount at which carried at close of period [Abstract]      
Land 568,000    
Buildings & Improvements 8,992,000    
Total 9,560,000    
Accumulated Depreciation (361,000)    
Year of Construction or Acquisition 2011    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Healthcare [Member] | Wells Clinic - Hibbing, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,463,000 [1]    
Initial Cost to Company [Abstract]      
Land 162,000    
Buildings & Improvements 2,497,000    
Costs capitalized subsequent to acquisition 2,000    
Gross amount at which carried at close of period [Abstract]      
Land 162,000    
Buildings & Improvements 2,499,000    
Total 2,661,000    
Accumulated Depreciation (565,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 38,622,000 [1]    
Initial Cost to Company [Abstract]      
Land 20,121,000    
Buildings & Improvements 89,744,000    
Costs capitalized subsequent to acquisition 15,907,000    
Gross amount at which carried at close of period [Abstract]      
Land 20,349,000    
Buildings & Improvements 105,423,000    
Total 125,772,000    
Accumulated Depreciation (23,688,000)    
Additions during year [Abstract]      
Additions 5,900,000 0 3,914,000
Commercial-Industrial [Member] | API Building - Duluth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 796,000 [1]    
Initial Cost to Company [Abstract]      
Land 115,000    
Buildings & Improvements 1,605,000    
Costs capitalized subsequent to acquisition 3,000    
Gross amount at which carried at close of period [Abstract]      
Land 115,000    
Buildings & Improvements 1,608,000    
Total 1,723,000    
Accumulated Depreciation (363,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Bloomington 2000 W 94th Street - Bloomington, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 2,133,000 [5]    
Buildings & Improvements 4,097,000 [5]    
Costs capitalized subsequent to acquisition 1,185,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 2,172,000 [5]    
Buildings & Improvements 5,243,000 [5]    
Total 7,415,000 [5]    
Accumulated Depreciation (972,000) [5]    
Year of Construction or Acquisition 2006 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Industrial [Member] | Bodycote Industrial Building - Eden Prairie, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,046,000 [1]    
Initial Cost to Company [Abstract]      
Land 198,000    
Buildings & Improvements 1,154,000    
Costs capitalized subsequent to acquisition 800,000    
Gross amount at which carried at close of period [Abstract]      
Land 198,000    
Buildings & Improvements 1,954,000    
Total 2,152,000    
Accumulated Depreciation (858,000)    
Year of Construction or Acquisition 1992    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Brooklyn Park 7401 Boone Avenue - Brooklyn Park, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 7,411,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,368,000    
Buildings & Improvements 11,643,000    
Costs capitalized subsequent to acquisition 2,121,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,368,000    
Buildings & Improvements 13,764,000    
Total 15,132,000    
Accumulated Depreciation (3,801,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Cedar Lake Business Center - St. Louis Park, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,276,000 [1]    
Initial Cost to Company [Abstract]      
Land 895,000    
Buildings & Improvements 2,810,000    
Costs capitalized subsequent to acquisition 68,000    
Gross amount at which carried at close of period [Abstract]      
Land 895,000    
Buildings & Improvements 2,878,000    
Total 3,773,000    
Accumulated Depreciation (444,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Clive 2075 NW 94th Street - Clive, IA [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,175,000 [1]    
Initial Cost to Company [Abstract]      
Land 408,000    
Buildings & Improvements 2,611,000    
Costs capitalized subsequent to acquisition 47,000    
Gross amount at which carried at close of period [Abstract]      
Land 408,000    
Buildings & Improvements 2,658,000    
Total 3,066,000    
Accumulated Depreciation (246,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Dixon Avenue Industrial Park - Des Moines, IA [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 1,439,000    
Buildings & Improvements 10,758,000    
Costs capitalized subsequent to acquisition 1,609,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,439,000    
Buildings & Improvements 12,367,000    
Total 13,806,000    
Accumulated Depreciation (3,501,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Eagan 2785 & 2795 Highway 55 - Eagan, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 3,058,000    
Buildings & Improvements 2,570,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 3,058,000    
Buildings & Improvements 2,570,000    
Total 5,628,000    
Accumulated Depreciation (337,000)    
Year of Construction or Acquisition 2008    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Fargo 1320 45th Street N - Fargo, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 395,000    
Buildings & Improvements 3,518,000    
Costs capitalized subsequent to acquisition 247,000    
Gross amount at which carried at close of period [Abstract]      
Land 395,000    
Buildings & Improvements 3,765,000    
Total 4,160,000    
Accumulated Depreciation (273,000)    
Year of Construction or Acquisition 2010    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Lexington Commerce Center - Eagan, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,348,000 [1]    
Initial Cost to Company [Abstract]      
Land 453,000    
Buildings & Improvements 4,352,000    
Costs capitalized subsequent to acquisition 1,982,000    
Gross amount at which carried at close of period [Abstract]      
Land 480,000    
Buildings & Improvements 6,307,000    
Total 6,787,000    
Accumulated Depreciation (2,407,000)    
Year of Construction or Acquisition 1999    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Lighthouse - Duluth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 836,000 [1]    
Initial Cost to Company [Abstract]      
Land 90,000    
Buildings & Improvements 1,788,000    
Costs capitalized subsequent to acquisition 7,000    
Gross amount at which carried at close of period [Abstract]      
Land 90,000    
Buildings & Improvements 1,795,000    
Total 1,885,000    
Accumulated Depreciation (408,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Metal Improvement Company - New Brighton, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 240,000    
Buildings & Improvements 2,189,000    
Costs capitalized subsequent to acquisition 78,000    
Gross amount at which carried at close of period [Abstract]      
Land 240,000    
Buildings & Improvements 2,267,000    
Total 2,507,000    
Accumulated Depreciation (648,000)    
Year of Construction or Acquisition 2002    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Minnetonka 13600 County Road 62 - Minnetonka, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,427,000 [1]    
Initial Cost to Company [Abstract]      
Land 809,000    
Buildings & Improvements 434,000    
Costs capitalized subsequent to acquisition 2,459,000    
Gross amount at which carried at close of period [Abstract]      
Land 809,000    
Buildings & Improvements 2,893,000    
Total 3,702,000    
Accumulated Depreciation (308,000)    
Year of Construction or Acquisition 2009    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Minot IPS - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 416,000    
Buildings & Improvements 5,484,000    
Costs capitalized subsequent to acquisition 62,000    
Gross amount at which carried at close of period [Abstract]      
Land 416,000    
Buildings & Improvements 5,546,000    
Total 5,962,000    
Accumulated Depreciation (59,000)    
Year of Construction or Acquisition 2012    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Roseville 2929 Long Lake Road - Roseville, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 1,966,000    
Buildings & Improvements 7,272,000    
Costs capitalized subsequent to acquisition 1,729,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,000,000    
Buildings & Improvements 8,967,000    
Total 10,967,000    
Accumulated Depreciation (1,506,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Stone Container - Fargo, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,426,000 [1]    
Initial Cost to Company [Abstract]      
Land 440,000    
Buildings & Improvements 6,597,000    
Costs capitalized subsequent to acquisition 104,000    
Gross amount at which carried at close of period [Abstract]      
Land 440,000    
Buildings & Improvements 6,701,000    
Total 7,141,000    
Accumulated Depreciation (2,608,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Stone Container - Roseville, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 4,500,000 [1]    
Initial Cost to Company [Abstract]      
Land 810,000    
Buildings & Improvements 7,440,000    
Costs capitalized subsequent to acquisition 254,000    
Gross amount at which carried at close of period [Abstract]      
Land 882,000    
Buildings & Improvements 7,622,000    
Total 8,504,000    
Accumulated Depreciation (2,176,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Urbandale 3900 106th Street - Urbandale, IA [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 10,702,000 [1]    
Initial Cost to Company [Abstract]      
Land 3,680,000    
Buildings & Improvements 9,893,000    
Costs capitalized subsequent to acquisition 1,215,000    
Gross amount at which carried at close of period [Abstract]      
Land 3,721,000    
Buildings & Improvements 11,067,000    
Total 14,788,000    
Accumulated Depreciation (1,732,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Winsted Industrial Building - Winsted, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 100,000    
Buildings & Improvements 901,000    
Costs capitalized subsequent to acquisition 53,000    
Gross amount at which carried at close of period [Abstract]      
Land 100,000    
Buildings & Improvements 954,000    
Total 1,054,000    
Accumulated Depreciation (358,000)    
Year of Construction or Acquisition 2001    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Industrial [Member] | Woodbury 1865 Woodlane - Woodbury, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,679,000 [1]    
Initial Cost to Company [Abstract]      
Land 1,108,000    
Buildings & Improvements 2,628,000    
Costs capitalized subsequent to acquisition 1,884,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,123,000    
Buildings & Improvements 4,497,000    
Total 5,620,000    
Accumulated Depreciation (683,000)    
Year of Construction or Acquisition 2007    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 35,220,000 [1]    
Initial Cost to Company [Abstract]      
Land 19,099,000    
Buildings & Improvements 86,904,000    
Costs capitalized subsequent to acquisition 26,533,000    
Gross amount at which carried at close of period [Abstract]      
Land 21,192,000    
Buildings & Improvements 111,344,000    
Total 132,536,000    
Accumulated Depreciation (27,218,000)    
Additions during year [Abstract]      
Additions 1,240,000 2,316,000 7,169,000
Commercial-Retail [Member] | 17 South Main - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 81,000 [1]    
Initial Cost to Company [Abstract]      
Land 15,000    
Buildings & Improvements 75,000    
Costs capitalized subsequent to acquisition 197,000    
Gross amount at which carried at close of period [Abstract]      
Land 17,000    
Buildings & Improvements 270,000    
Total 287,000    
Accumulated Depreciation (196,000)    
Year of Construction or Acquisition 2000    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Anoka Strip Center - Anoka, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 123,000    
Buildings & Improvements 602,000    
Costs capitalized subsequent to acquisition 25,000    
Gross amount at which carried at close of period [Abstract]      
Land 134,000    
Buildings & Improvements 616,000    
Total 750,000    
Accumulated Depreciation (160,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Arrowhead First International Bank - Minot ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 75,000    
Buildings & Improvements 1,165,000    
Costs capitalized subsequent to acquisition 360,000    
Gross amount at which carried at close of period [Abstract]      
Land 75,000    
Buildings & Improvements 1,525,000    
Total 1,600,000    
Accumulated Depreciation (3,000)    
Year of Construction or Acquisition 2013    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Burnsville 1 Strip Center - Burnsville, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 329,000 [1]    
Initial Cost to Company [Abstract]      
Land 208,000    
Buildings & Improvements 773,000    
Costs capitalized subsequent to acquisition 205,000    
Gross amount at which carried at close of period [Abstract]      
Land 208,000    
Buildings & Improvements 978,000    
Total 1,186,000    
Accumulated Depreciation (256,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Burnsville 2 Strip Center - Burnsville, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 259,000 [1]    
Initial Cost to Company [Abstract]      
Land 291,000    
Buildings & Improvements 469,000    
Costs capitalized subsequent to acquisition 214,000    
Gross amount at which carried at close of period [Abstract]      
Land 294,000    
Buildings & Improvements 680,000    
Total 974,000    
Accumulated Depreciation (196,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Champlin South Pond - Champlin, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,473,000 [1]    
Initial Cost to Company [Abstract]      
Land 842,000    
Buildings & Improvements 2,703,000    
Costs capitalized subsequent to acquisition 69,000    
Gross amount at which carried at close of period [Abstract]      
Land 866,000    
Buildings & Improvements 2,748,000    
Total 3,614,000    
Accumulated Depreciation (650,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Chan West Village - Chanhassen, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 13,052,000 [1]    
Initial Cost to Company [Abstract]      
Land 5,035,000    
Buildings & Improvements 14,665,000    
Costs capitalized subsequent to acquisition 1,987,000    
Gross amount at which carried at close of period [Abstract]      
Land 5,606,000    
Buildings & Improvements 16,081,000    
Total 21,687,000    
Accumulated Depreciation (4,298,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Dakota West Plaza - Minot , ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 364,000 [1]    
Initial Cost to Company [Abstract]      
Land 92,000    
Buildings & Improvements 493,000    
Costs capitalized subsequent to acquisition 30,000    
Gross amount at which carried at close of period [Abstract]      
Land 106,000    
Buildings & Improvements 509,000    
Total 615,000    
Accumulated Depreciation (95,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Duluth 4615 Grand - Duluth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 677,000 [1]    
Initial Cost to Company [Abstract]      
Land 130,000    
Buildings & Improvements 1,800,000    
Costs capitalized subsequent to acquisition 4,000    
Gross amount at which carried at close of period [Abstract]      
Land 131,000    
Buildings & Improvements 1,803,000    
Total 1,934,000    
Accumulated Depreciation (407,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Duluth Denfeld Retail - Duluth, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,235,000 [1]    
Initial Cost to Company [Abstract]      
Land 276,000    
Buildings & Improvements 4,699,000    
Costs capitalized subsequent to acquisition 160,000    
Gross amount at which carried at close of period [Abstract]      
Land 297,000    
Buildings & Improvements 4,838,000    
Total 5,135,000    
Accumulated Depreciation (1,114,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Eagan Community - Eagan, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 702,000    
Buildings & Improvements 1,243,000    
Costs capitalized subsequent to acquisition 800,000    
Gross amount at which carried at close of period [Abstract]      
Land 703,000    
Buildings & Improvements 2,042,000    
Total 2,745,000    
Accumulated Depreciation (498,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Fargo Express Community - Fargo, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 938,000 [1]    
Initial Cost to Company [Abstract]      
Land 374,000    
Buildings & Improvements 1,420,000    
Costs capitalized subsequent to acquisition 777,000    
Gross amount at which carried at close of period [Abstract]      
Land 386,000    
Buildings & Improvements 2,185,000    
Total 2,571,000    
Accumulated Depreciation (430,000)    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Fargo Express Community - Fargo, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Year of Construction or Acquisition 2003    
Commercial-Retail [Member] | Fargo Express Community - Fargo, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Year of Construction or Acquisition 2005    
Commercial-Retail [Member] | Forest Lake Auto - Forest Lake, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 50,000 [5]    
Buildings & Improvements 446,000 [5]    
Costs capitalized subsequent to acquisition 13,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 50,000 [5]    
Buildings & Improvements 459,000 [5]    
Total 509,000 [5]    
Accumulated Depreciation (120,000) [5]    
Year of Construction or Acquisition 2003 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Retail [Member] | Forest Lake Westlake Center - Forest Lake, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 2,446,000    
Buildings & Improvements 5,304,000    
Costs capitalized subsequent to acquisition 487,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,480,000    
Buildings & Improvements 5,757,000    
Total 8,237,000    
Accumulated Depreciation (1,485,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Grand Forks Carmike - Grand Forks, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,541,000 [1]    
Initial Cost to Company [Abstract]      
Land 184,000    
Buildings & Improvements 2,360,000    
Costs capitalized subsequent to acquisition 2,000    
Gross amount at which carried at close of period [Abstract]      
Land 184,000    
Buildings & Improvements 2,362,000    
Total 2,546,000    
Accumulated Depreciation (1,092,000)    
Year of Construction or Acquisition 1994    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Grand Forks Medpark Mall - Grand Forks, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 681,000    
Buildings & Improvements 4,808,000    
Costs capitalized subsequent to acquisition 251,000    
Gross amount at which carried at close of period [Abstract]      
Land 722,000    
Buildings & Improvements 5,018,000    
Total 5,740,000    
Accumulated Depreciation (1,683,000)    
Year of Construction or Acquisition 2000    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Jamestown Buffalo Mall - Jamestown, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,331,000 [1]    
Initial Cost to Company [Abstract]      
Land 566,000    
Buildings & Improvements 5,551,000    
Costs capitalized subsequent to acquisition 3,036,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,114,000    
Buildings & Improvements 8,039,000    
Total 9,153,000    
Accumulated Depreciation (1,486,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Jamestown Business Center - Jamestown, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 466,000 [1]    
Initial Cost to Company [Abstract]      
Land 297,000    
Buildings & Improvements 1,023,000    
Costs capitalized subsequent to acquisition 1,332,000    
Gross amount at which carried at close of period [Abstract]      
Land 333,000    
Buildings & Improvements 2,319,000    
Total 2,652,000    
Accumulated Depreciation (844,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Kalispell Retail Center - Kalispell, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,280,000 [1]    
Initial Cost to Company [Abstract]      
Land 250,000    
Buildings & Improvements 2,250,000    
Costs capitalized subsequent to acquisition 973,000    
Gross amount at which carried at close of period [Abstract]      
Land 253,000    
Buildings & Improvements 3,220,000    
Total 3,473,000    
Accumulated Depreciation (761,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Lakeville Strip Center - Lakeville, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 932,000 [1]    
Initial Cost to Company [Abstract]      
Land 46,000    
Buildings & Improvements 1,142,000    
Costs capitalized subsequent to acquisition 852,000    
Gross amount at which carried at close of period [Abstract]      
Land 94,000    
Buildings & Improvements 1,946,000    
Total 2,040,000    
Accumulated Depreciation (613,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Minot 1400 31st Ave - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 1,026,000 [5]    
Buildings & Improvements 6,143,000 [5]    
Costs capitalized subsequent to acquisition 4,352,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 1,038,000 [5]    
Buildings & Improvements 10,483,000 [5]    
Total 11,521,000 [5]    
Accumulated Depreciation (1,054,000) [5]    
Year of Construction or Acquisition 2010 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Retail [Member] | Minot Arrowhead - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 100,000 [5]    
Buildings & Improvements 3,007,000 [5]    
Costs capitalized subsequent to acquisition 5,272,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 116,000 [5]    
Buildings & Improvements 8,263,000 [5]    
Total 8,379,000 [5]    
Accumulated Depreciation (1,403,000) [5]    
Year of Construction or Acquisition 1973 [5]    
Commercial-Retail [Member] | Minot Arrowhead - Minot, ND [Member] | Minimum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 15 years 6 months [5]    
Commercial-Retail [Member] | Minot Arrowhead - Minot, ND [Member] | Maximum [Member]
      
Gross amount at which carried at close of period [Abstract]      
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Retail [Member] | Minot Plaza - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 795,000 [1]    
Initial Cost to Company [Abstract]      
Land 50,000    
Buildings & Improvements 453,000    
Costs capitalized subsequent to acquisition 147,000    
Gross amount at which carried at close of period [Abstract]      
Land 80,000    
Buildings & Improvements 570,000    
Total 650,000    
Accumulated Depreciation (296,000)    
Year of Construction or Acquisition 1993    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Monticello C Store - Monticello, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 65,000 [5]    
Buildings & Improvements 770,000 [5]    
Costs capitalized subsequent to acquisition 37,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 97,000 [5]    
Buildings & Improvements 775,000 [5]    
Total 872,000 [5]    
Accumulated Depreciation (206,000) [5]    
Year of Construction or Acquisition 2003 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Retail [Member] | Omaha Barnes & Noble - Omaha, NE [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 2,418,000 [1]    
Initial Cost to Company [Abstract]      
Land 600,000    
Buildings & Improvements 3,099,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 600,000    
Buildings & Improvements 3,099,000    
Total 3,699,000    
Accumulated Depreciation (1,356,000)    
Year of Construction or Acquisition 1995    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Pine City C-Store - Pine City, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 83,000    
Buildings & Improvements 357,000    
Costs capitalized subsequent to acquisition 12,000    
Gross amount at which carried at close of period [Abstract]      
Land 83,000    
Buildings & Improvements 369,000    
Total 452,000    
Accumulated Depreciation (96,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Pine City Evergreen Square - Pine City, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 154,000    
Buildings & Improvements 2,646,000    
Costs capitalized subsequent to acquisition 606,000    
Gross amount at which carried at close of period [Abstract]      
Land 385,000    
Buildings & Improvements 3,021,000    
Total 3,406,000    
Accumulated Depreciation (890,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Rochester Maplewood Square - Rochester, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1],[5]    
Initial Cost to Company [Abstract]      
Land 3,275,000 [5]    
Buildings & Improvements 8,610,000 [5]    
Costs capitalized subsequent to acquisition 1,966,000 [5]    
Gross amount at which carried at close of period [Abstract]      
Land 3,652,000 [5]    
Buildings & Improvements 10,199,000 [5]    
Total 13,851,000 [5]    
Accumulated Depreciation (3,229,000) [5]    
Year of Construction or Acquisition 1999 [5]    
Life on which depreciation in latest income statement is computed 40 years [5]    
Commercial-Retail [Member] | St. Cloud Westgate - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,008,000 [1]    
Initial Cost to Company [Abstract]      
Land 918,000    
Buildings & Improvements 5,535,000    
Costs capitalized subsequent to acquisition 1,669,000    
Gross amount at which carried at close of period [Abstract]      
Land 941,000    
Buildings & Improvements 7,181,000    
Total 8,122,000    
Accumulated Depreciation (1,481,000)    
Year of Construction or Acquisition 2004    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Weston Retail - Weston, WI [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 79,000    
Buildings & Improvements 1,575,000    
Costs capitalized subsequent to acquisition 27,000    
Gross amount at which carried at close of period [Abstract]      
Land 80,000    
Buildings & Improvements 1,601,000    
Total 1,681,000    
Accumulated Depreciation (408,000)    
Year of Construction or Acquisition 2003    
Life on which depreciation in latest income statement is computed 40 years    
Commercial-Retail [Member] | Weston Walgreens - Weston, WI [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 3,041,000 [1]    
Initial Cost to Company [Abstract]      
Land 66,000    
Buildings & Improvements 1,718,000    
Costs capitalized subsequent to acquisition 671,000    
Gross amount at which carried at close of period [Abstract]      
Land 67,000    
Buildings & Improvements 2,388,000    
Total 2,455,000    
Accumulated Depreciation (412,000)    
Year of Construction or Acquisition 2006    
Life on which depreciation in latest income statement is computed 40 years    
Subtotal [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 1,049,206,000 [1]    
Initial Cost to Company [Abstract]      
Land 190,207,000    
Buildings & Improvements 1,577,356,000    
Costs capitalized subsequent to acquisition 265,407,000    
Gross amount at which carried at close of period [Abstract]      
Land 207,499,000    
Buildings & Improvements 1,825,471,000    
Total 2,032,970,000    
Accumulated Depreciation (420,421,000)    
Unimproved Land [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 20,808,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 695,000    
Gross amount at which carried at close of period [Abstract]      
Land 21,503,000    
Buildings & Improvements 0    
Total 21,503,000    
Accumulated Depreciation 0    
Unimproved Land [Member] | Badger Hills Rochester, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 1,050,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 1,050,000    
Buildings & Improvements 0    
Total 1,050,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2012    
Unimproved Land [Member] | Bismarck 4916 - Bismarck, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 3,250,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 3,250,000    
Buildings & Improvements 0    
Total 3,250,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2013    
Unimproved Land [Member] | Bismarck 700 E Main - Bismarck, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 314,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 558,000    
Gross amount at which carried at close of period [Abstract]      
Land 872,000    
Buildings & Improvements 0    
Total 872,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2008    
Unimproved Land [Member] | Cypress Court - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 447,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 447,000    
Buildings & Improvements 0    
Total 447,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2012    
Unimproved Land [Member] | Eagan - Eagan, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 423,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 423,000    
Buildings & Improvements 0    
Total 423,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2006    
Unimproved Land [Member] | Georgetown Square - Grand Chute, WI [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 1,860,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 1,860,000    
Buildings & Improvements 0    
Total 1,860,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2006    
Unimproved Land [Member] | Grand Forks 2150 Grand Forks, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 1,600,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 1,600,000    
Buildings & Improvements 0    
Total 1,600,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2013    
Unimproved Land [Member] | Grand Forks Grand Forks, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 4,278,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 4,278,000    
Buildings & Improvements 0    
Total 4,278,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2012    
Unimproved Land [Member] | Kalispell - Kalispell, MT [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 1,400,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 23,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,423,000    
Buildings & Improvements 0    
Total 1,423,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2003    
Unimproved Land [Member] | Minot Southgate Lot 4 Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 1,882,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 1,882,000    
Buildings & Improvements 0    
Total 1,882,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2013    
Unimproved Land [Member] | Monticello - Monticello, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 115,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 2,000    
Gross amount at which carried at close of period [Abstract]      
Land 117,000    
Buildings & Improvements 0    
Total 117,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2006    
Unimproved Land [Member] | Renaissance Heights - Williston, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 2,373,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 2,373,000    
Buildings & Improvements 0    
Total 2,373,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2012    
Unimproved Land [Member] | River Falls - River Falls, WI [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 176,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 3,000    
Gross amount at which carried at close of period [Abstract]      
Land 179,000    
Buildings & Improvements 0    
Total 179,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2003    
Unimproved Land [Member] | Urbandale - Urbandale, IA [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 5,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 109,000    
Gross amount at which carried at close of period [Abstract]      
Land 114,000    
Buildings & Improvements 0    
Total 114,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2009    
Unimproved Land [Member] | Weston - Weston, WI [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 812,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 812,000    
Buildings & Improvements 0    
Total 812,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2006    
Unimproved Land [Member] | Williston - Williston, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 823,000    
Buildings & Improvements 0    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 823,000    
Buildings & Improvements 0    
Total 823,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2012    
Development in Progress [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 12,894,000    
Buildings & Improvements 27,023,000    
Costs capitalized subsequent to acquisition 6,594,000    
Gross amount at which carried at close of period [Abstract]      
Land 12,907,000    
Buildings & Improvements 33,604,000    
Total 46,511,000    
Accumulated Depreciation 0    
Development in Progress [Member] | Cypress Court - St. Cloud, MN [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 1,136,000    
Buildings & Improvements 4,610,000    
Costs capitalized subsequent to acquisition 713,000    
Gross amount at which carried at close of period [Abstract]      
Land 1,136,000    
Buildings & Improvements 5,323,000    
Total 6,459,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2012    
Development in Progress [Member] | Arcata [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 2,088,000    
Buildings & Improvements 569,000    
Costs capitalized subsequent to acquisition 0    
Gross amount at which carried at close of period [Abstract]      
Land 2,088,000    
Buildings & Improvements 569,000    
Total 2,657,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2013    
Development in Progress [Member] | Chateau II - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 61,000    
Buildings & Improvements 189,000    
Costs capitalized subsequent to acquisition 8,000    
Gross amount at which carried at close of period [Abstract]      
Land 61,000    
Buildings & Improvements 197,000    
Total 258,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2013    
Development in Progress [Member] | Commons at Southgate - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 3,691,000    
Buildings & Improvements 2,180,000    
Costs capitalized subsequent to acquisition 594,000    
Gross amount at which carried at close of period [Abstract]      
Land 3,691,000    
Buildings & Improvements 2,774,000    
Total 6,465,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2013    
Development in Progress [Member] | Landing at Southgate - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 2,262,000    
Buildings & Improvements 4,054,000    
Costs capitalized subsequent to acquisition 1,104,000    
Gross amount at which carried at close of period [Abstract]      
Land 2,262,000    
Buildings & Improvements 5,158,000    
Total 7,420,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2013    
Development in Progress [Member] | Renaissance Heights I - Minot, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 3,080,000    
Buildings & Improvements 5,895,000    
Costs capitalized subsequent to acquisition 1,102,000    
Gross amount at which carried at close of period [Abstract]      
Land 3,080,000    
Buildings & Improvements 6,997,000    
Total 10,077,000    
Accumulated Depreciation 0    
Year of Construction or Acquisition 2013    
Development in Progress [Member] | River Ridge - Bismarck, ND [Member]
      
Real Estate And Accumulated Depreciation [Abstract]      
Encumbrances 0 [1]    
Initial Cost to Company [Abstract]      
Land 576,000    
Buildings & Improvements 9,526,000    
Costs capitalized subsequent to acquisition 3,073,000    
Gross amount at which carried at close of period [Abstract]      
Land 589,000    
Buildings & Improvements 12,586,000    
Total 13,175,000    
Accumulated Depreciation $ 0    
Year of Construction or Acquisition 2008    
[1] Amounts in this column are the mortgages payable balances as of April 30, 2013. These amounts do not include amounts owing under the Company’s multi-bank line of credit or under the Company’s construction loans.
[2] The net basis of the Company’s real estate investments for Federal Income Tax purposes was approximately $1.5 billion, $1.4 billion and $1.2 billion at April 30, 2013, 2012 and 2011, respectively.
[3] Consists of miscellaneous disposed assets and assets moved to Development in Progress.
[4] Consists of miscellaneous disposed assets.
[5] As of April 30, 2013, this property was included in the collateral pool securing the Company’s $60.0 million multi-bank line of credit. The Company may add and remove eligible properties from the collateral pool if certain minimum collateral requirements are satisfied. Advances under the facility may not exceed 60% of the value of properties provided as security.