Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Document Fiscal Year Focus	2015
Other expense (income):
Gain on sale of real estate	$ (803)	$ (715)
Parent Company [Member]
Revenues:
Minimum rent	101,305	94,536
Percentage rent	1,808	1,384
Recoveries from tenants and other income	31,048	31,041
Management, transaction, and other fees	6,238	6,319
Total revenues	140,399	133,280
Operating expenses:
Depreciation and amortization	35,992	37,905
Operating and maintenance	21,172	20,505
General and administrative	16,378	14,198
Real estate taxes	15,131	14,799
Other operating expenses	1,166	2,173
Total operating expenses	89,839	89,580
Other expense (income):
Interest expense, net of interest income of $266 and $216 for the three months ended March 31, 2015 and 2014, respectively	26,633	27,134
Provision for impairment	0	225
Early extinguishment of debt	61	0
Net investment income, including unrealized (gains) losses of ($417) and $107 for the three months ended March 31, 2015 and 2014, respectively	(634)	(192)
Total other expense	25,938	27,167
Income from operations before equity in income of investments in real estate partnerships	24,622	16,533
Equity in income of investments in real estate partnerships	5,567	7,808
Income from operations	30,189	24,341
Gain on sale of real estate	(803)	(715)
Net income	30,992	25,056
Noncontrolling interests:
Exchangeable operating partnership units	(49)	(42)
Limited partners’ interests in consolidated partnerships	(503)	(359)
Income attributable to noncontrolling interests	(552)	(401)
Net income attributable to the Company	30,440	24,655
Preferred stock dividends	(5,266)	(5,266)
Net income attributable to common stockholders	25,174	19,389
Income per common share/unit - basic:
Continuing operations (in dollars per share)	$ 0.27	$ 0.21
Income per common share/unit - diluted:
Continuing operations (in dollars per share)	$ 0.27	$ 0.21
Partnership Interest [Member]
Revenues:
Minimum rent	101,305	94,536
Percentage rent	1,808	1,384
Recoveries from tenants and other income	31,048	31,041
Management, transaction, and other fees	6,238	6,319
Total revenues	140,399	133,280
Operating expenses:
Depreciation and amortization	35,992	37,905
Operating and maintenance	21,172	20,505
General and administrative	16,378	14,198
Real estate taxes	15,131	14,799
Other operating expenses	1,166	2,173
Total operating expenses	89,839	89,580
Other expense (income):
Interest expense, net of interest income of $266 and $216 for the three months ended March 31, 2015 and 2014, respectively	26,633	27,134
Provision for impairment	0	225
Early extinguishment of debt	61	0
Net investment income, including unrealized (gains) losses of ($417) and $107 for the three months ended March 31, 2015 and 2014, respectively	(634)	(192)
Total other expense	25,938	27,167
Income from operations before equity in income of investments in real estate partnerships	24,622	16,533
Equity in income of investments in real estate partnerships	5,567	7,808
Income from operations	30,189	24,341
Gain on sale of real estate	(803)	(715)
Net income	30,992	25,056
Noncontrolling interests:
Limited partners’ interests in consolidated partnerships	(503)	(359)
Income attributable to noncontrolling interests	(503)	(359)
Net income attributable to the Company	30,489	24,697
Preferred unit distributions	(5,266)	(5,266)
Net income attributable to common unit holders	$ 25,223	$ 19,431
Income per common share/unit - basic:
Continuing operations (in dollars per share)	$ 0.27	$ 0.21
Income per common share/unit - diluted:
Continuing operations (in dollars per share)	$ 0.27	$ 0.21