Noncontrolling Interests (Redeemable Preferred Units) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning Balance	$ 633
Net income	6	$ 1,023	$ 6,046
Redemption of redeemable preferred units (Series Four Preferred Units)	(633)	(17,373)	(43,070)
Conversion of redeemable preferred units (Series Two Preferred Units) to common units		33,306	16,494
Ending Balance	0	633
Redeemable Preferred Units [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning Balance	633	51,312	110,876
Net income	6	1,023	6,046
Distributions	(6)	(1,023)	(6,046)
Redemption of redeemable preferred units (Series Four Preferred Units)	(633)	(17,373)	(43,070)
Conversion of redeemable preferred units (Series Two Preferred Units) to common units		(33,306)	(16,494)
Ending Balance	$ 0	$ 633	$ 51,312