Reportable Segments Table (Details) - USD ($)	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Severance Costs	$ 0	$ 0		$ (102,000)	$ (84,000)
Reimbursed Expenses	(717,000)	(988,000)		(1,828,000)	(1,920,000)
Dividends, Preferred Stock	0	(1,178,000)		0	(2,955,000)
Net income (loss) available to common stockholders	7,951,000	(2,223,000)		15,155,000	2,979,000
Office Segment [Member]
Segment Reporting Information [Line Items]
Net operating property income, including discontinued operations	59,269,000	48,821,000		116,003,000	96,419,000
Residential lot and other sales, net of cost of sales	0	0		0	0
Fee income, Net of Reimbursed Expenses	0	0		0	0
Other Income	0	0		0	0
Severance Costs				0	0
General and Administrative Expense	0	0		0	0
Reimbursed Expenses	0	0		0	0
Interest Expense Including Discontinued Operations	0	0		0	0
Other nonoperating expense, including discontinued operations	0	0		0	0
Dividends, Preferred Stock		0			0
Funds from Operations Available to Common Stockholders	59,269,000	48,821,000		116,003,000	96,419,000
Retail Segment [Member]
Segment Reporting Information [Line Items]
Net operating property income, including discontinued operations	0	1,288,000		0	2,591,000
Residential lot and other sales, net of cost of sales	0	0		0	0
Fee income, Net of Reimbursed Expenses	0	0		0	0
Other Income	0	0		0	0
Severance Costs				0	0
General and Administrative Expense	0	0		0	0
Reimbursed Expenses	0	0		0	0
Interest Expense Including Discontinued Operations	0	0		0	0
Other nonoperating expense, including discontinued operations	0	0		0	0
Dividends, Preferred Stock		0			0
Funds from Operations Available to Common Stockholders	0	1,288,000		0	2,591,000
Land [Member]
Segment Reporting Information [Line Items]
Net operating property income, including discontinued operations	0	0		0	0
Residential lot and other sales, net of cost of sales	(324,000)	1,331,000		486,000	1,491,000
Fee income, Net of Reimbursed Expenses	0	0		0	0
Other Income	0	0		0	0
Severance Costs				0	0
General and Administrative Expense	0	0		0	0
Reimbursed Expenses	0	0		0	0
Interest Expense Including Discontinued Operations	0	0		0	0
Other nonoperating expense, including discontinued operations	0	0		0	0
Dividends, Preferred Stock		0			0
Funds from Operations Available to Common Stockholders	(324,000)	1,331,000		486,000	1,491,000
All Other Segments [Member]
Segment Reporting Information [Line Items]
Net operating property income, including discontinued operations	1,505,000	1,179,000		2,824,000	2,296,000
Residential lot and other sales, net of cost of sales	0	42,000		0	42,000
Fee income, Net of Reimbursed Expenses	1,704,000	2,025,000		3,520,000	4,363,000
Other Income	238,000	2,256,000		645,000	4,172,000
Severance Costs				(102,000)	(84,000)
General and Administrative Expense	(5,942,000)	(5,756,000)		(9,435,000)	(11,367,000)
Reimbursed Expenses	(717,000)	(988,000)		(1,828,000)	(1,920,000)
Interest Expense Including Discontinued Operations	(9,696,000)	(8,813,000)		(19,194,000)	(17,825,000)
Other nonoperating expense, including discontinued operations	(799,000)	(893,000)		(1,746,000)	(1,727,000)
Dividends, Preferred Stock		(4,708,000)			(6,485,000)
Funds from Operations Available to Common Stockholders	(13,707,000)	(15,656,000)		(25,316,000)	(28,535,000)
Total Segment [Member]
Segment Reporting Information [Line Items]
Net operating property income, including discontinued operations	60,774,000	51,288,000	$ 51,288,000	118,827,000	101,306,000	$ 101,306,000	$ 118,827,000
Residential lot and other sales, net of cost of sales	(324,000)	1,373,000	1,373,000	486,000	1,533,000	1,533,000	486,000
Fee income, Net of Reimbursed Expenses	1,704,000	2,025,000	2,025,000	3,520,000	4,363,000	4,363,000	3,520,000
Other Income	238,000	2,256,000	$ 2,256,000	645,000	4,172,000	$ 4,172,000	$ 645,000
Severance Costs				(102,000)	(84,000)
General and Administrative Expense	(5,942,000)	(5,756,000)		(9,435,000)	(11,367,000)
Reimbursed Expenses	(717,000)	(988,000)		(1,828,000)	(1,920,000)
Interest Expense Including Discontinued Operations	(9,696,000)	(8,813,000)		(19,194,000)	(17,825,000)
Other nonoperating expense, including discontinued operations	(799,000)	(893,000)		(1,746,000)	(1,727,000)
Dividends, Preferred Stock		(4,708,000)			(6,485,000)
Funds from Operations Available to Common Stockholders	45,238,000	35,784,000		91,173,000	71,966,000
Real estate depreciation and amortization, including Company's share of joint ventures	(37,277,000)	(38,022,000)		(75,743,000)	(74,974,000)
Gain on sale of depreciated investment properties, including Company's share of joint ventures	(10,000)	15,000		(275,000)	5,987,000
Net income (loss) available to common stockholders	$ 7,951,000	$ (2,223,000)		$ 15,155,000	$ 2,979,000