CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
REVENUE
Rental	$ 473,741	$ 408,640	$ 332,780
Other	1,769	1,612	657
Total revenue	475,510	410,252	333,437
EXPENSES
Depreciation and amortization	149,597	118,874	91,641
Interest	122,542	108,301	93,237
General and administrative	37,998	30,954	25,311
Property	7,269	6,018	5,805
Income taxes	1,430	1,470	1,393
Merger-related costs	7,899
Provisions for impairment	2,804	10	849
Total expenses	329,539	265,627	218,236
Income from continuing operations	145,971	144,625	115,201
Income from discontinued operations	13,181	12,407	15,583
Net income	159,152	157,032	130,784
Preferred stock dividends	(40,918)	(24,253)	(24,253)
Excess of redemption value over carrying value of preferred shares redeemed	(3,696)
Net income available to common stockholders	$ 114,538	$ 132,779	$ 106,531
Income from continuing operations:
Basic (in dollars per share)	$ 0.76	$ 0.95	$ 0.86
Diluted (in dollars per share)	$ 0.76	$ 0.95	$ 0.86
Net income:
Basic (in dollars per share)	$ 0.86	$ 1.05	$ 1.01
Diluted (in dollars per share)	$ 0.86	$ 1.05	$ 1.01
Weighted average common shares outstanding:
Basic (in shares)	132,817,472	126,142,696	105,869,637
Diluted (in shares)	132,884,933	126,189,399	105,942,721