Reportable Segments Table (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Severance Costs	$ 0	$ (520,000)	$ (84,000)	$ (520,000)
Reimbursed Expenses	(783,000)	(1,097,000)	(2,703,000)	(4,365,000)
Dividends, Preferred Stock	0	(1,777,000)	(2,955,000)	(8,231,000)
Net income available to common stockholders	19,322,000	59,381,000	22,299,000	106,975,000
Office Segment [Member]
Segment Reporting Information [Line Items]
Net operating property income, including discontinued operations	52,691,000	30,308,000	149,110,000	76,039,000
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
Gain on Sale of Third Party Management Operations		0		0
Severance Costs		0	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	0	0
Funds from Operations Available to Common Stockholders	52,691,000	30,308,000	149,110,000	76,039,000
Retail Segment [Member]
Segment Reporting Information [Line Items]
Net operating property income, including discontinued operations	1,221,000	3,663,000	3,813,000	12,255,000
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
Gain on Sale of Third Party Management Operations		0		0
Severance Costs		0	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	0	0
Funds from Operations Available to Common Stockholders	1,221,000	3,663,000	3,813,000	12,255,000
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	82,000	725,000	1,573,000	1,244,000
Fee income, Net of Reimbursed Expenses	0	0	0	0
Other Income	0	0	0	0
Gain on Sale of Third Party Management Operations		0		0
Severance Costs		0	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	0	0
Funds from Operations Available to Common Stockholders	82,000	725,000	1,573,000	1,244,000
All Other Segments [Member]
Segment Reporting Information [Line Items]
Net operating property income, including discontinued operations	1,200,000	861,000	3,496,000	1,280,000
Residential lot and other sales, net of cost of sales	0	(6,000)	42,000	154,000
Fee income, Net of Reimbursed Expenses	1,802,000	2,420,000	6,165,000	9,007,000
Other Income	399,000	303,000	4,563,000	2,649,000
Gain on Sale of Third Party Management Operations		4,531,000		4,531,000
Severance Costs		(520,000)	(84,000)	(520,000)
General and Administrative Expense	(5,021,000)	(6,635,000)	(16,388,000)	(17,257,000)
Reimbursed Expenses	(783,000)	(1,097,000)	(2,703,000)	(4,365,000)
Interest Expense Including Discontinued Operations	(8,660,000)	(7,224,000)	(26,485,000)	(20,442,000)
Other nonoperating expense, including discontinued operations	(1,255,000)	(8,326,000)	(2,974,000)	(10,843,000)
Dividends, Preferred Stock	0	(1,777,000)	(6,485,000)	(10,887,000)
Funds from Operations Available to Common Stockholders	(12,318,000)	(17,470,000)	(40,853,000)	(46,693,000)
Total Segment [Member]
Segment Reporting Information [Line Items]
Net operating property income, including discontinued operations	55,112,000	34,832,000	156,419,000	89,574,000
Residential lot and other sales, net of cost of sales	82,000	719,000	1,615,000	1,398,000
Fee income, Net of Reimbursed Expenses	1,802,000	2,420,000	6,165,000	9,007,000
Other Income	399,000	303,000	4,563,000	2,649,000
Gain on Sale of Third Party Management Operations		4,531,000		4,531,000
Severance Costs		(520,000)	(84,000)	(520,000)
General and Administrative Expense	(5,021,000)	(6,635,000)	(16,388,000)	(17,257,000)
Reimbursed Expenses	(783,000)	(1,097,000)	(2,703,000)	(4,365,000)
Interest Expense Including Discontinued Operations	(8,660,000)	(7,224,000)	(26,485,000)	(20,442,000)
Other nonoperating expense, including discontinued operations	(1,255,000)	(8,326,000)	(2,974,000)	(10,843,000)
Dividends, Preferred Stock	0	(1,777,000)	(6,485,000)	(10,887,000)
Funds from Operations Available to Common Stockholders	41,676,000	17,226,000	113,643,000	42,845,000
Real estate depreciation and amortization, including Company's share of joint ventures	(35,347,000)	(21,890,000)	(110,319,000)	(57,162,000)
Gain on sale of depreciated investment properties, including Company's share of joint ventures	12,993,000	67,435,000	18,975,000	124,682,000
Noncontrolling Interest Related to Gain on Sale of Depreciated Investment Properties		(3,390,000)		(3,390,000)
Net income available to common stockholders	$ 19,322,000	$ 59,381,000	$ 22,299,000	$ 106,975,000