Schedule I Condensed Financial Information Parent - Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities	$ 43,619	$ 328,860	$ 276,333
Net Cash Provided by (Used in) Investing Activities [Abstract]
Change in restricted cash	(15,569)	5,261	(42,502)
Net cash provided by/(used in) investing activities	16,613	(5,927)	42,373
Net Cash Provided by (Used in) Financing Activities [Abstract]
Payments on debt	0	(54,345)	(6,030)
Extinguishment of debt	84,170	120,224	326,051
Repurchases of common stock and common stock warrants	0	119,343	3,633
Cash dividends paid	0	31,910	0
Tax withholding on share-based awards	1,157	0	0
Net cash used in financing activities	(85,327)	(325,822)	(335,714)
Net (decrease)/increase in cash and cash equivalents	(25,095)	(2,889)	(17,008)
Cash and cash equivalents	165,994	191,089	193,978	$ 210,986
Parent Company [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities	(13,787)	202,989	162,118
Net Cash Provided by (Used in) Investing Activities [Abstract]
Change in restricted cash	(15,569)	5,261	(42,502)
Contributions to subsidiaries	0	0	1,633
Distributions from subsidiaries	50,000	51,832	25,000
Net cash provided by/(used in) investing activities	65,569	46,571	65,869
Net Cash Provided by (Used in) Financing Activities [Abstract]
Payments on debt	0	(39,319)	0
Extinguishment of debt	84,170	0	326,051
Repurchases of common stock and common stock warrants	0	119,343	3,633
Cash dividends paid	0	31,910	0
Tax withholding on share-based awards	1,157	0	0
Net cash used in financing activities	(85,327)	(190,572)	(329,684)
Net (decrease)/increase in cash and cash equivalents	(33,545)	58,988	(101,697)
Cash and cash equivalents	$ 40,838	$ 74,383	$ 15,395	$ 117,092