Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 segment	Jun. 30, 2013	Dec. 31, 2013
Segment information
Number of reportable segments (segment)			2
Total revenues	$ 387,227	$ 353,944	$ 762,796	$ 707,565
Income (loss) from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate	58,318	33,298	106,500	57,841
Total assets	16,717,736		16,717,736		14,959,001
Leverage rate assumption (as a percent)			100.00%
Marketing, general and administrative	23,872	21,514	47,128	42,582
Real Estate Segment
Segment information
Total revenues	347,513	307,213	668,998	608,126
Income (loss) from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate	24,318	(4,742)	26,918	(23,548)
Total assets	15,155,384		15,155,384		13,641,727
Debt and Preferred Equity Segment
Segment information
Total revenues	39,714	46,731	93,798	99,439
Income (loss) from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate	34,000	38,040	79,582	81,389
Total assets	$ 1,562,352		$ 1,562,352		$ 1,317,274