Schedule III - Real Estate and Accumulated Depreciation and Amortization - Schedule III (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 689,810
Land and Land Estates	456,134
Buildings and Improvements	3,476,106
Total	3,936,459	$ 3,533,172	$ 3,789,711	$ 3,671,560
Accumulated Depreciation and Amortization	890,969	844,931	812,207	795,486
Construction in progress	4,219	5,119
Unamortized debt issuance costs	$ (7,258)
Building and Improvements [Member] | Maximum [Member]
Real Estate and Accumulated Depreciation [Line Items]
Useful life computing depreciation in latest income statement (years)	40 years
Land Estates [Member] | Maximum [Member]
Real Estate and Accumulated Depreciation [Line Items]
Useful life computing depreciation in latest income statement (years)	51 years
Office Building [Member] | Glendale, Arizona [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Land and Land Estates	9,418
Buildings and Improvements	8,394
Total	17,812
Accumulated Depreciation and Amortization	3,553
Office Building [Member] | Phoenix, Arizona [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	5,585
Buildings and Improvements	36,923
Total	42,508
Accumulated Depreciation and Amortization	5,556
Office Building [Member] | Tempe, Arizona [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	0
Buildings and Improvements	13,086
Total	13,086
Accumulated Depreciation and Amortization	2,525
Office Building [Member] | Tucson, Arizona [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	681
Buildings and Improvements	4,037
Total	4,718
Accumulated Depreciation and Amortization	929
Office Building [Member] | Palo Alto, California [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	37,846
Land and Land Estates	12,398
Buildings and Improvements	16,977
Total	29,375
Accumulated Depreciation and Amortization	21,909
Office Building [Member] | Centenial, Colorado [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	4,851
Buildings and Improvements	19,351
Total	24,202
Accumulated Depreciation and Amortization	7,123
Office Building [Member] | Englewood, Colorado [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,207
Buildings and Improvements	27,851
Total	30,058
Accumulated Depreciation and Amortization	4,934
Office Building [Member] | Louisville, Colorado [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,657
Buildings and Improvements	11,645
Total	15,302
Accumulated Depreciation and Amortization	4,196
Office Building [Member] | Parachute, Colorado [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,400
Buildings and Improvements	10,751
Total	12,151
Accumulated Depreciation and Amortization	1,187
Office Building [Member] | Wallingford, Connecticut [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,049
Buildings and Improvements	4,773
Total	5,822
Accumulated Depreciation and Amortization	2,010
Office Building [Member] | Boca Raton, Florida [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	19,088
Land and Land Estates	4,290
Buildings and Improvements	17,160
Total	21,450
Accumulated Depreciation and Amortization	6,382
Office Building [Member] | Orlando, Florida [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,538
Buildings and Improvements	9,863
Total	13,401
Accumulated Depreciation and Amortization	6,737
Office Building [Member] | McDonough, Georgia [Member] | McDonough, GA Office Acquired Sep-12 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,443
Buildings and Improvements	11,794
Total	13,237
Accumulated Depreciation and Amortization	2,215
Office Building [Member] | McDonough, Georgia [Member] | McDonough, GA Office Acquired Sep-12, Property 2 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	693
Buildings and Improvements	6,405
Total	7,098
Accumulated Depreciation and Amortization	1,372
Office Building [Member] | Meridian, Idaho [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	8,428
Land and Land Estates	2,255
Buildings and Improvements	7,797
Total	10,052
Accumulated Depreciation and Amortization	2,142
Office Building [Member] | Schaumburg, Illinois [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	5,007
Buildings and Improvements	22,340
Total	27,347
Accumulated Depreciation and Amortization	6,225
Office Building [Member] | Columbus, Indiana [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	11,842
Land and Land Estates	235
Buildings and Improvements	45,729
Total	45,964
Accumulated Depreciation and Amortization	30,595
Office Building [Member] | Indianapolis, Indiana [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,700
Buildings and Improvements	18,591
Total	20,291
Accumulated Depreciation and Amortization	13,777
Office Building [Member] | Lenexa, Kansas [Member] | Lenexa, KS Office Acquired Jul-08 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	33,212
Land and Land Estates	6,909
Buildings and Improvements	41,966
Total	48,875
Accumulated Depreciation and Amortization	14,057
Office Building [Member] | Lenexa, Kansas [Member] | Lenexa, KS Office Acquired Sep-12 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	8,631
Land and Land Estates	2,828
Buildings and Improvements	6,075
Total	8,903
Accumulated Depreciation and Amortization	1,538
Office Building [Member] | Overland Park, Kansas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	32,828
Land and Land Estates	4,769
Buildings and Improvements	41,956
Total	46,725
Accumulated Depreciation and Amortization	15,769
Office Building [Member] | Baton Rouge, Louisiana [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,252
Buildings and Improvements	11,085
Total	12,337
Accumulated Depreciation and Amortization	4,924
Office Building [Member] | Oakland, Maine [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	8,370
Land and Land Estates	551
Buildings and Improvements	8,774
Total	9,325
Accumulated Depreciation and Amortization	1,922
Office Building [Member] | Auburn Hill, Michigan [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	4,416
Buildings and Improvements	30,012
Total	34,428
Accumulated Depreciation and Amortization	4,120
Office Building [Member] | Livonia, Michigan [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	935
Buildings and Improvements	13,714
Total	14,649
Accumulated Depreciation and Amortization	3,347
Office Building [Member] | Kansas City, Missouri [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	15,618
Land and Land Estates	2,433
Buildings and Improvements	20,154
Total	22,587
Accumulated Depreciation and Amortization	7,553
Office Building [Member] | Saint Joseph, Missouri [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	607
Buildings and Improvements	14,004
Total	14,611
Accumulated Depreciation and Amortization	2,355
Office Building [Member] | Pascagoula, Mississippi [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	618
Buildings and Improvements	3,677
Total	4,295
Accumulated Depreciation and Amortization	868
Office Building [Member] | Charlotte, North Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	45,400
Land and Land Estates	3,771
Buildings and Improvements	47,064
Total	50,835
Accumulated Depreciation and Amortization	1,262
Office Building [Member] | Omaha, Nebraska [Member] | Omaha, NE Office Acquired Dec-13 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,058
Buildings and Improvements	32,343
Total	34,401
Accumulated Depreciation and Amortization	3,856
Office Building [Member] | Omaha, Nebraska [Member] | Omaha, NE Office Acquired Nov-05 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,566
Buildings and Improvements	8,324
Total	10,890
Accumulated Depreciation and Amortization	3,070
Office Building [Member] | Rockaway, New Jersey [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	4,646
Buildings and Improvements	23,143
Total	27,789
Accumulated Depreciation and Amortization	7,088
Office Building [Member] | Wall, New Jersey [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	11,924
Land and Land Estates	8,985
Buildings and Improvements	26,961
Total	35,946
Accumulated Depreciation and Amortization	14,671
Office Building [Member] | Whippany, New Jersey [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	12,704
Land and Land Estates	4,063
Buildings and Improvements	19,711
Total	23,774
Accumulated Depreciation and Amortization	9,018
Office Building [Member] | Las Vegas, Nevada [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	12,099
Buildings and Improvements	53,164
Total	65,263
Accumulated Depreciation and Amortization	14,947
Office Building [Member] | Columbus, Ohio [Member] | Columbus, OH Office Acquired Dec-10 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,594
Buildings and Improvements	10,481
Total	12,075
Accumulated Depreciation and Amortization	1,834
Office Building [Member] | Columbus, Ohio [Member] | Columbus, OH Office Acquired Jul-11 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	432
Buildings and Improvements	2,773
Total	3,205
Accumulated Depreciation and Amortization	451
Office Building [Member] | Westerville, Ohio [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,085
Buildings and Improvements	9,411
Total	11,496
Accumulated Depreciation and Amortization	3,322
Office Building [Member] | Eugene, Oregon [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,541
Buildings and Improvements	13,098
Total	14,639
Accumulated Depreciation and Amortization	2,290
Office Building [Member] | Redmond, Oregon [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,064
Buildings and Improvements	8,316
Total	10,380
Accumulated Depreciation and Amortization	1,913
Office Building [Member] | Jessup, Pennsylvania [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,520
Buildings and Improvements	17,688
Total	20,208
Accumulated Depreciation and Amortization	3,792
Office Building [Member] | Philadelphia, Pennsylvania [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	13,209
Buildings and Improvements	57,071
Total	70,280
Accumulated Depreciation and Amortization	39,639
Office Building [Member] | Florence, South Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	774
Buildings and Improvements	3,629
Total	4,403
Accumulated Depreciation and Amortization	622
Office Building [Member] | Fort Mill, South Carolina [Member] | Fort Mill, SC Office, Acquired Nov-04 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,798
Buildings and Improvements	26,038
Total	27,836
Accumulated Depreciation and Amortization	18,142
Office Building [Member] | Fort Mill, South Carolina [Member] | Fort Mill, SC Office, Acquired Dec-02 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,601
Buildings and Improvements	15,340
Total	18,941
Accumulated Depreciation and Amortization	5,833
Office Building [Member] | Kingsport, Tennessee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	513
Buildings and Improvements	403
Total	916
Accumulated Depreciation and Amortization	233
Office Building [Member] | Knoxville, Tennessee [Member] | Knoxville, TN Office Acquired Sep-12 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	621
Buildings and Improvements	6,487
Total	7,108
Accumulated Depreciation and Amortization	1,428
Office Building [Member] | Knoxville, Tennessee [Member] | Knoxville, TN Office Acquired Mar-05 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,079
Buildings and Improvements	11,351
Total	12,430
Accumulated Depreciation and Amortization	7,505
Office Building [Member] | Memphis, Tennessee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	5,291
Buildings and Improvements	97,032
Total	102,323
Accumulated Depreciation and Amortization	27,795
Office Building [Member] | Allen, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	5,591
Buildings and Improvements	25,421
Total	31,012
Accumulated Depreciation and Amortization	10,705
Office Building [Member] | Arlington, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,274
Buildings and Improvements	15,309
Total	16,583
Accumulated Depreciation and Amortization	2,980
Office Building [Member] | Carrollton, Texas [Member] | Carrollton, TX Office Acquired Jun-07 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,599
Buildings and Improvements	22,050
Total	24,649
Accumulated Depreciation and Amortization	9,273
Office Building [Member] | Carrollton, Texas [Member] | Carrollton, TX Office Acquired Jun-07, Property 2 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	828
Buildings and Improvements	0
Total	828
Accumulated Depreciation and Amortization	0
Office Building [Member] | Houston, Texas [Member] | Houston, TX Office Acquired Apr-05 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,875
Buildings and Improvements	17,323
Total	19,198
Accumulated Depreciation and Amortization	8,982
Office Building [Member] | Houston, Texas [Member] | Houston, TX Office Acquired Apr-05, Property 2 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,875
Buildings and Improvements	10,959
Total	12,834
Accumulated Depreciation and Amortization	8,176
Office Building [Member] | Houston, Texas [Member] | Houston, TX Office Acquired Mar-04 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	16,613
Buildings and Improvements	63,770
Total	80,383
Accumulated Depreciation and Amortization	20,604
Office Building [Member] | Irving, Texas [Member] | Irving, TX Office Acquired May-07 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	7,476
Buildings and Improvements	45,985
Total	53,461
Accumulated Depreciation and Amortization	21,479
Office Building [Member] | Irving, Texas [Member] | Irving, TX Office Acquired Jun-07 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	4,889
Buildings and Improvements	30,192
Total	35,081
Accumulated Depreciation and Amortization	12,645
Office Building [Member] | Lake Jackson, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	192,451
Land and Land Estates	7,435
Buildings and Improvements	141,436
Total	148,871
Accumulated Depreciation and Amortization	6,182
Office Building [Member] | Mission, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,556
Buildings and Improvements	2,911
Total	5,467
Accumulated Depreciation and Amortization	903
Office Building [Member] | San Antonio, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,800
Buildings and Improvements	15,619
Total	18,419
Accumulated Depreciation and Amortization	12,110
Office Building [Member] | Westlake, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,361
Buildings and Improvements	26,591
Total	28,952
Accumulated Depreciation and Amortization	11,913
Office Building [Member] | Hampton, Virginia [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,333
Buildings and Improvements	12,132
Total	14,465
Accumulated Depreciation and Amortization	5,147
Office Building [Member] | Herndon, Virginia [Member] | Herndon, VA Office Acquired Dec-99 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	5,127
Buildings and Improvements	25,293
Total	30,420
Accumulated Depreciation and Amortization	10,626
Office Building [Member] | Herndon, Virginia [Member] | Herndon, VA Office Acquired Jun-07 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	9,409
Buildings and Improvements	14,951
Total	24,360
Accumulated Depreciation and Amortization	6,126
Office Building [Member] | Midlothian, Virginia [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,100
Buildings and Improvements	12,767
Total	13,867
Accumulated Depreciation and Amortization	8,601
Office Building [Member] | Richmond, Virginia [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	57,500
Land and Land Estates	7,329
Buildings and Improvements	89,810
Total	97,139
Accumulated Depreciation and Amortization	8,817
Office Building [Member] | Huntington, West Virginia [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,368
Buildings and Improvements	9,527
Total	10,895
Accumulated Depreciation and Amortization	1,918
Industrial Property [Member] | Anniston, Alabama [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,201
Buildings and Improvements	16,771
Total	17,972
Accumulated Depreciation and Amortization	2,369
Industrial Property [Member] | Moody, Alabama [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	654
Buildings and Improvements	9,943
Total	10,597
Accumulated Depreciation and Amortization	7,251
Industrial Property [Member] | Opelika, Alabama [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	134
Buildings and Improvements	33,183
Total	33,317
Accumulated Depreciation and Amortization	579
Industrial Property [Member] | Orlando, Florida [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,030
Buildings and Improvements	10,869
Total	11,899
Accumulated Depreciation and Amortization	3,371
Industrial Property [Member] | Tampa, Florida [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,160
Buildings and Improvements	8,526
Total	10,686
Accumulated Depreciation and Amortization	6,457
Industrial Property [Member] | Lavonia, Georgia [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	7,010
Land and Land Estates	171
Buildings and Improvements	7,657
Total	7,828
Accumulated Depreciation and Amortization	1,155
Industrial Property [Member] | McDonough, Georgia [Member] | McDonough, GA Industrial Acquired Aug-17 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	5,441
Buildings and Improvements	52,762
Total	58,203
Accumulated Depreciation and Amortization	912
Industrial Property [Member] | McDonough, Georgia [Member] | McDonough, GA Industrial Acquired Dec-06 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,463
Buildings and Improvements	24,811
Total	27,274
Accumulated Depreciation and Amortization	7,188
Industrial Property [Member] | Thomson, Georgia [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	909
Buildings and Improvements	7,746
Total	8,655
Accumulated Depreciation and Amortization	995
Industrial Property [Member] | Edwardsville, Illinois [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	4,593
Buildings and Improvements	34,251
Total	38,844
Accumulated Depreciation and Amortization	1,416
Industrial Property [Member] | Rantoul, Illinois [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,304
Buildings and Improvements	32,562
Total	33,866
Accumulated Depreciation and Amortization	3,579
Industrial Property [Member] | Rockford, Illinois [Member] | Rockford, IL Industrial Acquired Dec-06 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	371
Buildings and Improvements	2,573
Total	2,944
Accumulated Depreciation and Amortization	789
Industrial Property [Member] | Rockford, Illinois [Member] | Rockford, IL Industrial Acquired Dec-06, Property 2 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	509
Buildings and Improvements	5,289
Total	5,798
Accumulated Depreciation and Amortization	1,595
Industrial Property [Member] | Romeoville, Illinois [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	7,524
Buildings and Improvements	40,167
Total	47,691
Accumulated Depreciation and Amortization	1,798
Industrial Property [Member] | Lafayette, Indiana [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	662
Buildings and Improvements	15,578
Total	16,240
Accumulated Depreciation and Amortization	200
Industrial Property [Member] | Lebanon, Indiana [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,100
Buildings and Improvements	29,443
Total	31,543
Accumulated Depreciation and Amortization	1,108
Industrial Property [Member] | Plymouth, Indiana [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	254
Buildings and Improvements	8,101
Total	8,355
Accumulated Depreciation and Amortization	1,529
Industrial Property [Member] | New Century, Kansas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	0
Buildings and Improvements	13,198
Total	13,198
Accumulated Depreciation and Amortization	491
Industrial Property [Member] | Dry Ridge, Kentucky [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	560
Buildings and Improvements	12,553
Total	13,113
Accumulated Depreciation and Amortization	5,453
Industrial Property [Member] | Elizabethtown, Kentucky [Member] | Elizabethtown, KY Industrial Acquired Jun-05 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	890
Buildings and Improvements	26,868
Total	27,758
Accumulated Depreciation and Amortization	11,671
Industrial Property [Member] | Elizabethtown, Kentucky [Member] | Elizabethtown, KY Industrial Acquired Jun-05, Property 2 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	352
Buildings and Improvements	4,862
Total	5,214
Accumulated Depreciation and Amortization	2,112
Industrial Property [Member] | Hopkinsville, Kentucky [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	631
Buildings and Improvements	16,154
Total	16,785
Accumulated Depreciation and Amortization	7,453
Industrial Property [Member] | Owensboro, Kentucky [Member] | Owensboro, KY Industrial Acquired Jun-05 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	393
Buildings and Improvements	11,956
Total	12,349
Accumulated Depreciation and Amortization	5,978
Industrial Property [Member] | Owensboro, Kentucky [Member] | Owensboro, KY Industrial Acquired Dec-06 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	819
Buildings and Improvements	2,439
Total	3,258
Accumulated Depreciation and Amortization	1,014
Industrial Property [Member] | Shreveport, Louisiana [Member] | Shreveport, LA Industrial Acquired Jun-12 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,078
Buildings and Improvements	10,134
Total	11,212
Accumulated Depreciation and Amortization	2,050
Industrial Property [Member] | Shreveport, Louisiana [Member] | Shreveport, LA Industrial Acquired Mar-07 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	860
Buildings and Improvements	21,840
Total	22,700
Accumulated Depreciation and Amortization	5,892
Industrial Property [Member] | North Berwick, Maine [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	1,992
Land and Land Estates	1,383
Buildings and Improvements	35,659
Total	37,042
Accumulated Depreciation and Amortization	9,678
Industrial Property [Member] | Detroit, Michigan [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,133
Buildings and Improvements	25,009
Total	26,142
Accumulated Depreciation and Amortization	2,602
Industrial Property [Member] | Kalamazoo, Michigan [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,942
Buildings and Improvements	14,169
Total	16,111
Accumulated Depreciation and Amortization	3,036
Industrial Property [Member] | Marshall, Michigan [Member] | Marshall, MI Industrial Acquired Sep-12 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	143
Buildings and Improvements	4,302
Total	4,445
Accumulated Depreciation and Amortization	2,469
Industrial Property [Member] | Marshall, Michigan [Member] | Marshall, MI Industrial Acquired Aug-87 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	40
Buildings and Improvements	2,236
Total	2,276
Accumulated Depreciation and Amortization	1,164
Industrial Property [Member] | Plymouth, Michigan [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,296
Buildings and Improvements	15,819
Total	18,115
Accumulated Depreciation and Amortization	6,079
Industrial Property [Member] | Romulus, Michigan [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,438
Buildings and Improvements	33,786
Total	36,224
Accumulated Depreciation and Amortization	296
Industrial Property [Member] | Warren, Michigan [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	972
Buildings and Improvements	42,521
Total	43,493
Accumulated Depreciation and Amortization	296
Industrial Property [Member] | Minneapolis, Minnesota [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,886
Buildings and Improvements	1,922
Total	3,808
Accumulated Depreciation and Amortization	322
Industrial Property [Member] | Byhalia, Mississippi [Member] | Byhalia, MS Industrial Property Acquired Sep-17 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,751
Buildings and Improvements	31,236
Total	32,987
Accumulated Depreciation and Amortization	455
Industrial Property [Member] | Byhalia, Mississippi [Member] | Byhalia, MS Industrial Property Acquired May-11 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,006
Buildings and Improvements	35,795
Total	36,801
Accumulated Depreciation and Amortization	5,131
Industrial Property [Member] | Canton, Mississippi [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	5,077
Buildings and Improvements	71,289
Total	76,366
Accumulated Depreciation and Amortization	9,497
Industrial Property [Member] | Olive Branch, Mississippi [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	198
Buildings and Improvements	10,276
Total	10,474
Accumulated Depreciation and Amortization	7,283
Industrial Property [Member] | Henderson, North Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,488
Buildings and Improvements	5,953
Total	7,441
Accumulated Depreciation and Amortization	2,400
Industrial Property [Member] | Lumberton, North Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	405
Buildings and Improvements	12,049
Total	12,454
Accumulated Depreciation and Amortization	4,263
Industrial Property [Member] | Shelby, North Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,421
Buildings and Improvements	18,862
Total	20,283
Accumulated Depreciation and Amortization	4,593
Industrial Property [Member] | Statesville, North Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	891
Buildings and Improvements	16,771
Total	17,662
Accumulated Depreciation and Amortization	5,355
Industrial Property [Member] | Durham, New Hampshire [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,464
Buildings and Improvements	18,094
Total	21,558
Accumulated Depreciation and Amortization	6,441
Industrial Property [Member] | North Las Vegas, Nevada [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,244
Buildings and Improvements	21,732
Total	24,976
Accumulated Depreciation and Amortization	2,317
Industrial Property [Member] | Erwin, New York [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	6,991
Land and Land Estates	1,648
Buildings and Improvements	12,514
Total	14,162
Accumulated Depreciation and Amortization	2,450
Industrial Property [Member] | Long Island City, New York [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	43,334
Land and Land Estates	0
Buildings and Improvements	42,759
Total	42,759
Accumulated Depreciation and Amortization	13,737
Industrial Property [Member] | Chillicothe, Ohio [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	735
Buildings and Improvements	9,021
Total	9,756
Accumulated Depreciation and Amortization	2,745
Industrial Property [Member] | Cincinnati, Ohio [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,049
Buildings and Improvements	8,784
Total	9,833
Accumulated Depreciation and Amortization	2,785
Industrial Property [Member] | Columbus, Ohio [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,990
Buildings and Improvements	10,742
Total	12,732
Accumulated Depreciation and Amortization	3,837
Industrial Property [Member] | Glenwillow, Ohio [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,228
Buildings and Improvements	24,530
Total	26,758
Accumulated Depreciation and Amortization	7,176
Industrial Property [Member] | Hebron, Ohio [Member] | Hebron, OH Industrial, Acquired Dec-97 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,063
Buildings and Improvements	4,947
Total	6,010
Accumulated Depreciation and Amortization	1,827
Industrial Property [Member] | Hebron, Ohio [Member] | Hebron, OH Industrial, Acquired Dec-01 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,681
Buildings and Improvements	8,179
Total	9,860
Accumulated Depreciation and Amortization	3,349
Industrial Property [Member] | Streetsboro, Ohio [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	16,931
Land and Land Estates	2,441
Buildings and Improvements	25,282
Total	27,723
Accumulated Depreciation and Amortization	8,824
Industrial Property [Member] | Wilsonville, Oregon [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	6,815
Buildings and Improvements	32,380
Total	39,195
Accumulated Depreciation and Amortization	1,771
Industrial Property [Member] | Bristol, Pennsylvania [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,508
Buildings and Improvements	15,863
Total	18,371
Accumulated Depreciation and Amortization	7,137
Industrial Property [Member] | Anderson, South Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	4,663
Buildings and Improvements	44,987
Total	49,650
Accumulated Depreciation and Amortization	3,298
Industrial Property [Member] | Chester, South Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	7,271
Land and Land Estates	1,629
Buildings and Improvements	8,470
Total	10,099
Accumulated Depreciation and Amortization	1,650
Industrial Property [Member] | Duncan, South Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	884
Buildings and Improvements	8,626
Total	9,510
Accumulated Depreciation and Amortization	2,393
Industrial Property [Member] | Laurens, South Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	5,552
Buildings and Improvements	21,908
Total	27,460
Accumulated Depreciation and Amortization	7,203
Industrial Property [Member] | Cleveland, Tennessee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,871
Buildings and Improvements	29,743
Total	31,614
Accumulated Depreciation and Amortization	865
Industrial Property [Member] | Crossville, Tennessee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	545
Buildings and Improvements	6,999
Total	7,544
Accumulated Depreciation and Amortization	4,218
Industrial Property [Member] | Franklin, Tennessee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	0
Buildings and Improvements	5,673
Total	5,673
Accumulated Depreciation and Amortization	2,596
Industrial Property [Member] | Jackson, Tennessee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,454
Buildings and Improvements	49,026
Total	50,480
Accumulated Depreciation and Amortization	525
Industrial Property [Member] | Lewisburg, Tennessee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	173
Buildings and Improvements	10,865
Total	11,038
Accumulated Depreciation and Amortization	1,244
Industrial Property [Member] | Memphis, Tennessee [Member] | Memphis, TN Industrial Acquired Feb-88 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,054
Buildings and Improvements	11,538
Total	12,592
Accumulated Depreciation and Amortization	11,463
Industrial Property [Member] | Memphis, Tennessee [Member] | Memphis, TN Industrial Acquired Dec-06 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	214
Buildings and Improvements	1,902
Total	2,116
Accumulated Depreciation and Amortization	20
Industrial Property [Member] | Millington, Tennessee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	723
Buildings and Improvements	19,383
Total	20,106
Accumulated Depreciation and Amortization	12,022
Industrial Property [Member] | Smyrna, Tennessee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,793
Buildings and Improvements	93,940
Total	95,733
Accumulated Depreciation and Amortization	1,031
Industrial Property [Member] | Arlington, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	589
Buildings and Improvements	7,750
Total	8,339
Accumulated Depreciation and Amortization	1,310
Industrial Property [Member] | Brookshire, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,388
Buildings and Improvements	16,614
Total	19,002
Accumulated Depreciation and Amortization	2,138
Industrial Property [Member] | Grand Prairie, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,166
Buildings and Improvements	17,985
Total	21,151
Accumulated Depreciation and Amortization	390
Industrial Property [Member] | Houston, Texas [Member] | Houston, TX Industrial Acquired Mar-15 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	4,674
Buildings and Improvements	19,540
Total	24,214
Accumulated Depreciation and Amortization	5,879
Industrial Property [Member] | Houston, Texas [Member] | Houston, TX Industrial Acquired Mar-13 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	15,055
Buildings and Improvements	57,949
Total	73,004
Accumulated Depreciation and Amortization	8,568
Industrial Property [Member] | Missouri City, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	14,555
Buildings and Improvements	5,895
Total	20,450
Accumulated Depreciation and Amortization	4,772
Industrial Property [Member] | San Antonio, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,311
Buildings and Improvements	36,644
Total	37,955
Accumulated Depreciation and Amortization	788
Industrial Property [Member] | Winchester, Virginia [Member] | Winchester, VA Industrial Acquired Dec-17 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,988
Buildings and Improvements	32,501
Total	34,489
Accumulated Depreciation and Amortization	0
Industrial Property [Member] | Winchester, Virginia [Member] | Winchester, VA Industrial Acquired Jun-07 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,823
Buildings and Improvements	12,276
Total	16,099
Accumulated Depreciation and Amortization	4,008
Industrial Property [Member] | Bingen, Washington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	0
Buildings and Improvements	18,075
Total	18,075
Accumulated Depreciation and Amortization	3,338
Industrial Property [Member] | Richland, Washington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	110,000
Land and Land Estates	1,293
Buildings and Improvements	126,947
Total	128,240
Accumulated Depreciation and Amortization	11,380
Industrial Property [Member] | Oak Creek, Wisconsin [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,015
Buildings and Improvements	15,300
Total	18,315
Accumulated Depreciation and Amortization	1,663
Other Property [Member] | Phoenix, Arizona [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,831
Buildings and Improvements	15,635
Total	17,466
Accumulated Depreciation and Amortization	4,918
Other Property [Member] | Manteca, California [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	187
Land and Land Estates	2,082
Buildings and Improvements	6,464
Total	8,546
Accumulated Depreciation and Amortization	2,041
Other Property [Member] | San Diego, California [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	119
Land and Land Estates	0
Buildings and Improvements	13,310
Total	13,310
Accumulated Depreciation and Amortization	3,637
Other Property [Member] | Venice, Florida [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	4,696
Buildings and Improvements	11,753
Total	16,449
Accumulated Depreciation and Amortization	6,755
Other Property [Member] | Albany, Georgia [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,468
Buildings and Improvements	5,137
Total	6,605
Accumulated Depreciation and Amortization	1,192
Other Property [Member] | Honolulu, Hawaii [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	8,259
Buildings and Improvements	7,398
Total	15,657
Accumulated Depreciation and Amortization	4,199
Other Property [Member] | Galesburg, Illinois [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	105
Land and Land Estates	91
Buildings and Improvements	250
Total	341
Accumulated Depreciation and Amortization	3
Other Property [Member] | Lawrence, Indiana [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	139
Buildings and Improvements	435
Total	574
Accumulated Depreciation and Amortization	0
Other Property [Member] | Baltimore, Maryland [Member] | Baltimore, MD Other Acquired Dec-15 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	5,000
Buildings and Improvements	0
Total	5,000
Accumulated Depreciation and Amortization	0
Other Property [Member] | Baltimore, Maryland [Member] | Baltimore, MD Other Acquired Dec-06 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	4,605
Buildings and Improvements	0
Total	4,605
Accumulated Depreciation and Amortization	0
Other Property [Member] | Jefferson, North Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	71
Buildings and Improvements	884
Total	955
Accumulated Depreciation and Amortization	281
Other Property [Member] | Thomasville, North Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	208
Buildings and Improvements	561
Total	769
Accumulated Depreciation and Amortization	104
Other Property [Member] | Vineland, New Jersey [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,698
Buildings and Improvements	12,790
Total	15,488
Accumulated Depreciation and Amortization	1,291
Other Property [Member] | Watertown, New York [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	176
Land and Land Estates	386
Buildings and Improvements	5,162
Total	5,548
Accumulated Depreciation and Amortization	1,713
Other Property [Member] | Lawton, Oklahoma [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	663
Buildings and Improvements	1,288
Total	1,951
Accumulated Depreciation and Amortization	538
Other Property [Member] | Charleston, South Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	6,987
Land and Land Estates	1,189
Buildings and Improvements	9,133
Total	10,322
Accumulated Depreciation and Amortization	4,244
Other Property [Member] | Florence, South Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	744
Buildings and Improvements	1,280
Total	2,024
Accumulated Depreciation and Amortization	160
Other Property [Member] | Antioch, Tennessee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,847
Buildings and Improvements	12,659
Total	16,506
Accumulated Depreciation and Amortization	2,923
Other Property [Member] | Chattanooga, Tennessee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	487
Buildings and Improvements	956
Total	1,443
Accumulated Depreciation and Amortization	175
Other Property [Member] | Paris, Tennessee [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	247
Buildings and Improvements	547
Total	794
Accumulated Depreciation and Amortization	220
Other Property [Member] | Farmers Branch, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,984
Buildings and Improvements	30,798
Total	34,782
Accumulated Depreciation and Amortization	12,375
Other Property [Member] | Houston, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	800
Buildings and Improvements	27,670
Total	28,470
Accumulated Depreciation and Amortization	21,400
Other Property [Member] | Danville, Virginia [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,454
Buildings and Improvements	0
Total	3,454
Accumulated Depreciation and Amortization	0
Other Property [Member] | Fairlea, West Virginia [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	123
Land and Land Estates	501
Buildings and Improvements	1,985
Total	2,486
Accumulated Depreciation and Amortization	600
LCIF [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	212,792
Land and Land Estates	88,589
Buildings and Improvements	705,649
Total	794,242	731,202	1,061,606	910,113
Accumulated Depreciation and Amortization	178,376	182,505	$ 199,690	$ 176,167
Construction in progress	4	$ 825
Unamortized debt issuance costs	$ (1,511)
LCIF [Member] | Building and Improvements [Member] | Maximum [Member]
Real Estate and Accumulated Depreciation [Line Items]
Useful life computing depreciation in latest income statement (years)	40 years
LCIF [Member] | Office Building [Member] | Phoenix, Arizona [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Land and Land Estates	5,585
Buildings and Improvements	36,923
Total	42,508
Accumulated Depreciation and Amortization	5,556
LCIF [Member] | Office Building [Member] | Centenial, Colorado [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	4,851
Buildings and Improvements	19,351
Total	24,202
Accumulated Depreciation and Amortization	7,123
LCIF [Member] | Office Building [Member] | Louisville, Colorado [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,657
Buildings and Improvements	11,645
Total	15,302
Accumulated Depreciation and Amortization	4,196
LCIF [Member] | Office Building [Member] | Wallingford, Connecticut [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,049
Buildings and Improvements	4,773
Total	5,822
Accumulated Depreciation and Amortization	2,010
LCIF [Member] | Office Building [Member] | Boca Raton, Florida [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	19,088
Land and Land Estates	4,290
Buildings and Improvements	17,160
Total	21,450
Accumulated Depreciation and Amortization	6,382
LCIF [Member] | Office Building [Member] | Schaumburg, Illinois [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	5,007
Buildings and Improvements	22,340
Total	27,347
Accumulated Depreciation and Amortization	6,225
LCIF [Member] | Office Building [Member] | Overland Park, Kansas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	32,828
Land and Land Estates	4,769
Buildings and Improvements	41,956
Total	46,725
Accumulated Depreciation and Amortization	15,769
LCIF [Member] | Office Building [Member] | Baton Rouge, Louisiana [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,252
Buildings and Improvements	11,085
Total	12,337
Accumulated Depreciation and Amortization	4,924
LCIF [Member] | Office Building [Member] | Charlotte, North Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	45,400
Land and Land Estates	3,771
Buildings and Improvements	47,064
Total	50,835
Accumulated Depreciation and Amortization	1,262
LCIF [Member] | Office Building [Member] | Fort Mill, South Carolina [Member] | Fort Mill, SC Office, Acquired Nov-04 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,798
Buildings and Improvements	26,038
Total	27,836
Accumulated Depreciation and Amortization	18,142
LCIF [Member] | Office Building [Member] | Fort Mill, South Carolina [Member] | Fort Mill, SC Office, Acquired Dec-02 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,601
Buildings and Improvements	15,340
Total	18,941
Accumulated Depreciation and Amortization	5,833
LCIF [Member] | Office Building [Member] | Carrollton, Texas [Member] | Carrollton, TX Office Acquired Jun-07 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,599
Buildings and Improvements	22,050
Total	24,649
Accumulated Depreciation and Amortization	9,273
LCIF [Member] | Office Building [Member] | Carrollton, Texas [Member] | Carrollton, TX Office Acquired Jun-07, Property 2 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	828
Buildings and Improvements	0
Total	828
Accumulated Depreciation and Amortization	0
LCIF [Member] | Office Building [Member] | Westlake, Texas [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,361
Buildings and Improvements	26,591
Total	28,952
Accumulated Depreciation and Amortization	11,913
LCIF [Member] | Office Building [Member] | Herndon, Virginia [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	5,127
Buildings and Improvements	25,293
Total	30,420
Accumulated Depreciation and Amortization	10,626
LCIF [Member] | Industrial Property [Member] | Moody, Alabama [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	654
Buildings and Improvements	9,943
Total	10,597
Accumulated Depreciation and Amortization	7,251
LCIF [Member] | Industrial Property [Member] | Tampa, Florida [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,160
Buildings and Improvements	8,526
Total	10,686
Accumulated Depreciation and Amortization	6,457
LCIF [Member] | Industrial Property [Member] | Romeoville, Illinois [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	7,524
Buildings and Improvements	40,167
Total	47,691
Accumulated Depreciation and Amortization	1,798
LCIF [Member] | Industrial Property [Member] | Marshall, Michigan [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	40
Buildings and Improvements	2,236
Total	2,276
Accumulated Depreciation and Amortization	1,164
LCIF [Member] | Industrial Property [Member] | Warren, Michigan [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	972
Buildings and Improvements	42,521
Total	43,493
Accumulated Depreciation and Amortization	296
LCIF [Member] | Industrial Property [Member] | Byhalia, Mississippi [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,006
Buildings and Improvements	35,795
Total	36,801
Accumulated Depreciation and Amortization	5,131
LCIF [Member] | Industrial Property [Member] | Olive Branch, Mississippi [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	198
Buildings and Improvements	10,276
Total	10,474
Accumulated Depreciation and Amortization	7,283
LCIF [Member] | Industrial Property [Member] | Shelby, North Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,421
Buildings and Improvements	18,917
Total	20,338
Accumulated Depreciation and Amortization	4,593
LCIF [Member] | Industrial Property [Member] | Hebron, Ohio [Member] | Hebron, OH Industrial, Acquired Dec-97 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,063
Buildings and Improvements	4,947
Total	6,010
Accumulated Depreciation and Amortization	1,827
LCIF [Member] | Industrial Property [Member] | Hebron, Ohio [Member] | Hebron, OH Industrial, Acquired Dec-01 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,681
Buildings and Improvements	8,179
Total	9,860
Accumulated Depreciation and Amortization	3,349
LCIF [Member] | Industrial Property [Member] | Bristol, Pennsylvania [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,508
Buildings and Improvements	15,863
Total	18,371
Accumulated Depreciation and Amortization	7,137
LCIF [Member] | Industrial Property [Member] | Grand Prairie, TX [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	3,166
Buildings and Improvements	17,985
Total	21,151
Accumulated Depreciation and Amortization	390
LCIF [Member] | Industrial Property [Member] | Richland, Washington [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	110,000
Land and Land Estates	1,293
Buildings and Improvements	126,947
Total	128,240
Accumulated Depreciation and Amortization	11,380
LCIF [Member] | Other Property [Member] | Albany, Georgia [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	1,468
Buildings and Improvements	5,137
Total	6,605
Accumulated Depreciation and Amortization	1,192
LCIF [Member] | Other Property [Member] | Honolulu, Hawaii [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	8,259
Buildings and Improvements	7,398
Total	15,657
Accumulated Depreciation and Amortization	4,199
LCIF [Member] | Other Property [Member] | Vineland, New Jersey [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	2,698
Buildings and Improvements	12,790
Total	15,488
Accumulated Depreciation and Amortization	1,291
LCIF [Member] | Other Property [Member] | Charleston, South Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	6,987
Land and Land Estates	1,189
Buildings and Improvements	9,133
Total	10,322
Accumulated Depreciation and Amortization	4,244
LCIF [Member] | Other Property [Member] | Florence, South Carolina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Land and Land Estates	744
Buildings and Improvements	1,280
Total	2,024
Accumulated Depreciation and Amortization	$ 160