Schedule III Real Estate and Accumulated Depreciation (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property
Balance, beginning of period	$ 738,596	$ 622,622	$ 234,262
Additions - property acquisitions			332,128
Additions - improvements	87,527	115,974	56,232
Balance, end of period	826,123	738,596	622,622
Accumulated Depreciation
Balance, beginning of period	64,428	32,943	16,207
Additions - depreciation, net of disposals	40,062	31,485	16,736
Balance, end of period	$ 104,490	$ 64,428	$ 32,943