Guarantor Financial Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Aug. 31, 2016	Oct. 31, 2013	Apr. 30, 2011	Mar. 31, 2011
Performance and payment guaranteed
Gain on early extinguishment of long-term debt	$ 3,967,000	$ 0	$ 0
2019 Senior Notes
Performance and payment guaranteed
Aggregate principal amount of notes issued					$ 250,000,000	$ 50,000,000	$ 300,000,000
Debt instrument, repurchased face amount				$ 100,000,000
Discount on debt extinguishment	5,000,000
Write off of deferred debt issuance cost	$ 1,000,000
Guarantor Subsidiaries | Guarantee on senior notes | 2019 Senior Notes
Performance and payment guaranteed
Aggregate principal amount of notes issued					$ 250,000,000	$ 350,000,000