Debt Obligations - Additional Information on Repurchase of Outstanding Unsecured Notes (Details) - USD ($)		12 Months Ended
	Jan. 14, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Extinguishment Of Debt [Line Items]
Principal		$ 0	$ 0	$ 376,174,000
Repurchase Amount		149,919,000	0	383,768,000
Loss on Early Extinguishment of Debt	$ (66,600,000)	$ (66,590,000)	$ 0	(7,594,000)
Acceleration of Deferred Financing				152,000
$250.0M 5.400% Guaranteed Notes due 2014 [Member]
Extinguishment Of Debt [Line Items]
Principal				218,549,000
Repurchase Amount				219,404,000
Loss on Early Extinguishment of Debt				(855,000)
Acceleration of Deferred Financing				9,000
7.50% Guaranteed Notes due May 15, 2015 [Member]
Extinguishment Of Debt [Line Items]
Principal				157,625,000
Repurchase Amount				164,364,000
Loss on Early Extinguishment of Debt				(6,739,000)
Acceleration of Deferred Financing				$ 143,000