CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Revenues:
Rental income	$ 160,880	$ 149,836
Property other income	15,447	15,321
Other income	317	141
Total revenues	176,644	165,298
Expenses:
Operating and maintenance	67,307	65,571
General and administrative	8,543	9,258
Interest	25,485	24,852
Depreciation and amortization	47,864	43,778
Other expenses	377	8
Impairment and other charges	181
Total expenses	149,757	143,467
Income from continuing operations, before gain on disposition of real estate	26,887	21,831
Gain on disposition of land	70
Gain on disposition of property	40,346
Income from continuing operations	67,303	21,831
Discontinued operations:
Income from discontinued operations		834
Gain on disposition of property		31,306
Discontinued operations		32,140
Net income	67,303	53,971
Net income attributable to noncontrolling interest	(9,945)	(8,180)
Net income attributable to common stockholders	$ 57,358	$ 45,791
Basic earnings per share data:
Income from continuing operations (in dollars per share)	$ 0.99	$ 0.32
Discontinued operations (in dollars per share)		$ 0.48
Net income attributable to common stockholders (in dollars per share)	$ 0.99	$ 0.80
Diluted earnings per share data:
Income from continuing operations (in dollars per share)	$ 0.98	$ 0.32
Discontinued operations (in dollars per share)		$ 0.47
Net income attributable to common stockholders (in dollars per share)	$ 0.98	$ 0.79
Weighted average number of shares outstanding:
Basic (in shares)	57,872,599	57,106,853
Diluted (in shares)	58,505,744	57,620,655