Comprehensive Income (Loss) - Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net income (loss)	$ 2,543	$ (170,914)	$ (4,172)	$ 1,615	$ 10,089	$ 6,420	$ 5,637	$ 1,845	$ (170,928)	$ 23,991	$ 13,370
Adjustment to pension liability									9,408	(28,802)	36,920
Tax (expense) benefit									(3,763)	11,521	(14,768)
Adjustment to pension liability									5,645	(17,281)	22,152
Foreign currency translation adjustment									(1,976)	(1,830)	(536)
Total other comprehensive income (loss), net of tax									3,669	(19,111)	21,616
Comprehensive income (loss)									(167,259)	4,880	$ 34,986
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Adjustment to pension liability									5,645	(17,281)
Accumulated Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign currency translation adjustment									$ (1,976)	$ (1,830)