Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 segment	Mar. 31, 2013	Dec. 31, 2013
Segment information
Number of reportable segments (segment)	2
Total revenues	$ 381,128	$ 359,953
Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate	51,266	28,428
Total assets	15,363,289		14,959,001
Leverage rate assumption (as a percent)	100.00%
Marketing, general and administrative	23,257	21,067
Real Estate Segment
Segment information
Total revenues	327,044	307,245
Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate	5,683	(14,922)
Total assets	13,855,420		13,641,727
Debt and Preferred Equity Segment
Segment information
Total revenues	54,084	52,708
Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate	45,583	43,350
Total assets	$ 1,507,869		$ 1,317,274