Condensed Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenues:
Property rental	$ 102,923	$ 75,844
Tenant reinsurance	10,221	8,557
Management fees	6,178	6,586
Total revenues	119,322	90,987
Expenses:
Property operations	34,437	26,596
Tenant reinsurance	1,910	1,848
Acquisition related costs	452	609
General and administrative	12,769	12,640
Depreciation and amortization	23,025	16,524
Total expenses	72,593	58,217
Income from operations	46,729	32,770
Interest expense	(17,366)	(18,071)
Non-cash interest expense related to amortization of discount on exchangeable senior notes		(444)
Interest income	184	275
Interest income on note receivable from Preferred Operating Partnership unit holder	1,213	1,213
Income before equity in earnings of real estate ventures and income tax expense	30,760	15,743
Equity in earnings of unconsolidated real estate ventures	2,623	2,296
Equity in earnings of unconsolidated real estate ventures - gain on sale of real estate assets and purchase of joint venture partners' interests	2,556	5,429
Income tax expense	(2,008)	(950)
Net income	33,931	22,518
Net income allocated to Preferred Operating Partnership noncontrolling interests	(1,717)	(1,649)
Net income allocated to Operating Partnership and other noncontrolling interests	(789)	(655)
Net income attributable to common stockholders	$ 31,425	$ 20,214
Net income per common share
Basic (in dollars per share)	$ 0.28	$ 0.21
Diluted (in dollars per share)	$ 0.28	$ 0.21
Weighted average number of shares
Basic (in shares)	110,809,924	94,888,078
Diluted (in shares)	114,967,087	99,927,352
Cash dividends paid per common share (in dollars per share)	$ 0.25	$ 0.20