Stockholders' Equity and Noncontrolling Interests (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Class of Stock [Line Items]
Income attributable to noncontrolling interests	$ 3,426	$ 2,474
Depositary shares outstanding	7.2
6.875 Series C Cumulative Redeemable Preferred Stock
Class of Stock [Line Items]
Depository shares to cumulative redeemable preferred stock ratio	1.00%
Percentage of redeemable preferred stock	6.875%
Cumulative redeemable preferred stock liquidation preference (in usd per share)	$ 25.00
Annual dividend on depositary shares (in usd per share)	$ 1.71875
Series C Cumulative Redeemable Preferred Stock
Class of Stock [Line Items]
Percentage of redeemable preferred stock	6.875%