Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Document Fiscal Year Focus			2014
Other expense (income):
Income Tax Expense (Benefit)	$ 1,180	$ 0	$ 1,546	$ 0
Discontinued operations, net:
Gain on sale of real estate, net of tax	(27,558)	(16,108)	(29,598)	(29,235)
Parent Company [Member]
Revenues:
Minimum rent	98,620	88,784	290,935	261,935
Percentage rent	371	415	2,301	2,257
Recoveries from tenants and other income	28,787	25,425	90,144	79,615
Management, transaction, and other fees	5,781	5,694	18,353	19,195
Total revenues	133,559	120,318	401,733	363,002
Operating expenses:
Depreciation and amortization	36,417	32,740	110,345	94,938
Operating and maintenance	18,149	16,778	58,152	51,400
General and administrative	14,463	15,001	43,883	47,942
Real estate taxes	14,832	13,351	44,529	40,332
Other operating expenses	2,062	907	5,665	4,005
Total operating expenses	85,923	78,777	262,574	238,617
Other expense (income):
Interest expense, net of interest income of $221 and $350, and $901 and $1,101 for the three and nine months ended September 30, 2014 and 2013, respectively	27,561	26,750	82,141	82,363
Provision for impairment	0	6,000	225	6,000
Net investment (income) loss, including unrealized losses (gains) of $472 and ($875), and $289 and ($1,724) for the three and nine months ended September 30, 2014 and 2013, respectively	(94)	(963)	(915)	(1,998)
Total other expense	27,467	31,787	81,451	86,365
Income from continuing operations before equity in income of investments in real estate partnerships and income taxes	20,169	9,754	57,708	38,020
Equity in income of investments in real estate partnerships	5,713	13,262	22,353	25,150
Income from continuing operations	25,882	23,016	80,061	63,170
Discontinued operations, net:
Operating income	0	1,540	0	6,863
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	0	16,052	0	27,462
Income from discontinued operations	0	17,592	0	34,325
Gain on sale of real estate, net of tax	(27,558)	(56)	(29,598)	(1,773)
Net income	53,440	40,664	109,659	99,268
Noncontrolling interests:
Exchangeable operating partnership units	(90)	(73)	(185)	(183)
Limited partners’ interests in consolidated partnerships	(142)	(327)	(863)	(872)
Income attributable to noncontrolling interests	(232)	(400)	(1,048)	(1,055)
Net income attributable to the Company	53,208	40,264	108,611	98,213
Preferred stock dividends	(5,266)	(5,266)	(15,797)	(15,797)
Net income attributable to common stockholders	47,942	34,998	92,814	82,416
Income per common share/unit - basic:
Continuing operations (in dollars per share)	$ 0.52	$ 0.19	$ 1.00	$ 0.52
Discontinued operations (in dollars per share)	$ 0.00	$ 0.19	$ 0.00	$ 0.38
Net income attributable to common stockholders (in dollars per share)	$ 0.52	$ 0.38	$ 1.00	$ 0.90
Income per common share/unit - diluted:
Continuing operations (in dollars per share)	$ 0.52	$ 0.19	$ 1.00	$ 0.52
Discontinued operations (in dollars per share)	$ 0.00	$ 0.19	$ 0.00	$ 0.38
Net income attributable to common stockholders (in dollars per share)	$ 0.52	$ 0.38	$ 1.00	$ 0.90
Partnership Interest [Member]
Revenues:
Minimum rent	98,620	88,784	290,935	261,935
Percentage rent	371	415	2,301	2,257
Recoveries from tenants and other income	28,787	25,425	90,144	79,615
Management, transaction, and other fees	5,781	5,694	18,353	19,195
Total revenues	133,559	120,318	401,733	363,002
Operating expenses:
Depreciation and amortization	36,417	32,740	110,345	94,938
Operating and maintenance	18,149	16,778	58,152	51,400
General and administrative	14,463	15,001	43,883	47,942
Real estate taxes	14,832	13,351	44,529	40,332
Other operating expenses	2,062	907	5,665	4,005
Total operating expenses	85,923	78,777	262,574	238,617
Other expense (income):
Interest expense, net of interest income of $221 and $350, and $901 and $1,101 for the three and nine months ended September 30, 2014 and 2013, respectively	27,561	26,750	82,141	82,363
Provision for impairment	0	6,000	225	6,000
Net investment (income) loss, including unrealized losses (gains) of $472 and ($875), and $289 and ($1,724) for the three and nine months ended September 30, 2014 and 2013, respectively	(94)	(963)	(915)	(1,998)
Total other expense	27,467	31,787	81,451	86,365
Income from continuing operations before equity in income of investments in real estate partnerships and income taxes	20,169	9,754	57,708	38,020
Equity in income of investments in real estate partnerships	5,713	13,262	22,353	25,150
Income from continuing operations	25,882	23,016	80,061	63,170
Discontinued operations, net:
Operating income	0	1,540	0	6,863
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	0	16,052	0	27,462
Income from discontinued operations	0	17,592	0	34,325
Gain on sale of real estate, net of tax	(27,558)	(56)	(29,598)	(1,773)
Net income	53,440	40,664	109,659	99,268
Noncontrolling interests:
Limited partners’ interests in consolidated partnerships	(142)	(327)	(863)	(872)
Income attributable to noncontrolling interests	(142)	(327)	(863)	(872)
Net income attributable to the Company	53,298	40,337	108,796	98,396
Preferred unit distributions	(5,266)	(5,266)	(15,797)	(15,797)
Net income attributable to common unit holders	$ 48,032	$ 35,071	$ 92,999	$ 82,599
Income per common share/unit - basic:
Continuing operations (in dollars per share)	$ 0.52	$ 0.19	$ 1.00	$ 0.52
Discontinued operations (in dollars per share)	$ 0.00	$ 0.19	$ 0.00	$ 0.38
Net income attributable to common unit holders (in dollars per share)	$ 0.52	$ 0.38	$ 1.00	$ 0.90
Income per common share/unit - diluted:
Continuing operations (in dollars per share)	$ 0.52	$ 0.19	$ 1.00	$ 0.52
Discontinued operations (in dollars per share)	$ 0.00	$ 0.19	$ 0.00	$ 0.38
Net income attributable to common unit holders (in dollars per share)	$ 0.52	$ 0.38	$ 1.00	$ 0.90