Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other expense (income):
Income tax expense (benefit) of taxable REIT subsidiary	$ 0	$ 490	$ 0	$ (118)
Discontinued operations, net:
Gain on sale of operating properties, net	16,052	0	27,462	8,605
Parent Company [Member]
Revenues:
Minimum rent	90,178	84,382	266,104	261,519
Percentage rent	415	378	2,257	1,935
Recoveries from tenants and other income	25,823	24,388	80,917	79,606
Management, transaction, and other fees	5,694	6,441	19,195	20,060
Total revenues	122,110	115,589	368,473	363,120
Operating expenses:
Depreciation and amortization	33,184	28,529	96,241	90,934
Operating and maintenance	17,040	15,808	52,222	51,012
General and administrative	15,001	15,641	47,942	45,783
Real estate taxes	13,553	12,884	41,030	41,212
Other expenses	917	1,150	3,986	3,596
Total operating expenses	79,695	74,012	241,421	232,537
Other expense (income):
Interest expense, net of interest income of $350 and $379, and $1,101 and $1,291 for the three and nine months ended September 30, 2013 and 2012, respectively	26,750	27,462	82,363	84,796
Provision for impairment	6,000	1,147	6,000	20,155
Gains (Losses) on Extinguishment of Debt	0	852	0	852
Net investment income from deferred compensation plan, including unrealized gains of $875 and $618, and $1,724 and $1,343 for the three and nine months ended September 30, 2013 and 2012, respectively	(963)	(752)	(1,998)	(1,836)
Total other expense	(31,787)	(28,709)	(86,365)	(103,967)
Income before equity in income of investments in real estate partnerships	10,628	12,868	40,687	26,616
Equity in income of investments in real estate partnerships	13,262	5,403	25,150	19,173
Income from continuing operations before tax	23,890	18,271	65,837	45,789
Income tax expense (benefit) of taxable REIT subsidiary	0	490	0	(118)
Income from continuing operations	23,890	17,781	65,837	45,907
Discontinued operations, net:
Operating income	666	1,811	4,196	1,350
Gain on sale of operating properties, net	16,052	0	27,462	8,605
Income from discontinued operations	16,718	1,811	31,658	9,955
Income before gain on sale of real estate	40,608	19,592	97,495	55,862
Gain on sale of real estate	(56)	(228)	(1,773)	(2,041)
Net income	40,664	19,820	99,268	57,903
Net Income (Loss) Attributable to Noncontrolling Interest, Preferred Unit Holders (Deprecated 2013-01-31)	0	0	0	629
Noncontrolling interests:
Exchangeable operating partnership units	(73)	(39)	(183)	(116)
Limited partners’ interests in consolidated partnerships	(327)	(212)	(872)	(636)
(Income) loss attributable to noncontrolling interests	(400)	(251)	(1,055)	(123)
Net income attributable to the Company	40,264	19,569	98,213	57,780
Preferred stock dividends	(5,266)	(7,932)	(15,797)	(27,265)
Net Income (Loss) attributable to Common Stockholders	34,998	11,637	82,416	30,515
Income per common share/unit - basic:
Continuing operations (in dollars per share)	$ 0.20	$ 0.11	$ 0.55	$ 0.23
Discontinued operations (in dollars per share)	$ 0.18	$ 0.02	$ 0.35	$ 0.11
Net income attributable to common stockholders (in dollars per share)	$ 0.38	$ 0.13	$ 0.90	$ 0.34
Income per common share/unit - diluted:
Continuing operations (in dollars per share)	$ 0.20	$ 0.11	$ 0.55	$ 0.23
Discontinued operations (in dollars per share)	$ 0.18	$ 0.02	$ 0.35	$ 0.11
Net income attributable to common stockholders (in dollars per share)	$ 0.38	$ 0.13	$ 0.90	$ 0.34
Partnership Interest [Member]
Revenues:
Minimum rent	90,178	84,382	266,104	261,519
Percentage rent	415	378	2,257	1,935
Recoveries from tenants and other income	25,823	24,388	80,917	79,606
Management, transaction, and other fees	5,694	6,441	19,195	20,060
Total revenues	122,110	115,589	368,473	363,120
Operating expenses:
Depreciation and amortization	33,184	28,529	96,241	90,934
Operating and maintenance	17,040	15,808	52,222	51,012
General and administrative	15,001	15,641	47,942	45,783
Real estate taxes	13,553	12,884	41,030	41,212
Other expenses	917	1,150	3,986	3,596
Total operating expenses	79,695	74,012	241,421	232,537
Other expense (income):
Interest expense, net of interest income of $350 and $379, and $1,101 and $1,291 for the three and nine months ended September 30, 2013 and 2012, respectively	26,750	27,462	82,363	84,796
Provision for impairment	6,000	1,147	6,000	20,155
Gains (Losses) on Extinguishment of Debt	0	852	0	852
Net investment income from deferred compensation plan, including unrealized gains of $875 and $618, and $1,724 and $1,343 for the three and nine months ended September 30, 2013 and 2012, respectively	(963)	(752)	(1,998)	(1,836)
Total other expense	(31,787)	(28,709)	(86,365)	(103,967)
Income before equity in income of investments in real estate partnerships	10,628	12,868	40,687	26,616
Equity in income of investments in real estate partnerships	13,262	5,403	25,150	19,173
Income from continuing operations before tax	23,890	18,271	65,837	45,789
Income tax expense (benefit) of taxable REIT subsidiary	0	490	0	(118)
Income from continuing operations	23,890	17,781	65,837	45,907
Discontinued operations, net:
Operating income	666	1,811	4,196	1,350
Gain on sale of operating properties, net	16,052	0	27,462	8,605
Income from discontinued operations	16,718	1,811	31,658	9,955
Income before gain on sale of real estate	40,608	19,592	97,495	55,862
Gain on sale of real estate	(56)	(228)	(1,773)	(2,041)
Net income	40,664	19,820	99,268	57,903
Noncontrolling interests:
Limited partners’ interests in consolidated partnerships	(327)	(212)	(872)	(636)
(Income) loss attributable to noncontrolling interests	(327)	(212)	(872)	(636)
Net income attributable to the Company	40,337	19,608	98,396	57,267
Preferred unit distributions	(5,266)	(7,932)	(15,797)	(26,636)
Net income attributable to common unit holders	$ 35,071	$ 11,676	$ 82,599	$ 30,631
Income per common share/unit - basic:
Continuing operations (in dollars per share)	$ 0.20	$ 0.11	$ 0.55	$ 0.23
Discontinued operations (in dollars per share)	$ 0.18	$ 0.02	$ 0.35	$ 0.11
Net income attributable to common unit holders (in dollars per share)	$ 0.38	$ 0.13	$ 0.90	$ 0.34
Income per common share/unit - diluted:
Continuing operations (in dollars per share)	$ 0.20	$ 0.11	$ 0.55	$ 0.23
Discontinued operations (in dollars per share)	$ 0.18	$ 0.02	$ 0.35	$ 0.11
Net income attributable to common unit holders (in dollars per share)	$ 0.38	$ 0.13	$ 0.90	$ 0.34