Consolidated Statements of Stockholders' Deficit - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2016		68,399
Beginning balance at Dec. 31, 2016	$ (117,563)	$ 114	$ (1,725,349)	$ 922,687	$ 693,682	$ (8,697)
Increase (Decrease) in Stockholders' Equity
Comprehensive income	65,749				62,444	3,305
Dividend forfeitures on restricted stock	285				285
Restricted stock awards (in shares)		636
Restricted stock awards	1	$ 1
Minimum tax withholding requirements (in shares)		(32)
Minimum tax withholding requirements	(252)			(252)
Stock-based compensation	6,025			6,025
Ending balance (in shares) at Sep. 30, 2017		69,003
Ending balance at Sep. 30, 2017	(45,755)	$ 115	(1,725,349)	928,460	756,411	(5,392)
Beginning balance (in shares) at Dec. 31, 2017		83,567
Beginning balance at Dec. 31, 2017	(185,921)	$ 130	(1,725,349)	1,001,315	543,814	(5,831)
Increase (Decrease) in Stockholders' Equity
Comprehensive income	10,390				10,941	(551)
Dividend forfeitures on restricted stock	42				42
Restricted stock awards (in shares)		397
Restricted stock awards	0
Minimum tax withholding requirements (in shares)		(79)
Minimum tax withholding requirements	(296)			(296)
Stock-based compensation	5,102			5,102
Ending balance (in shares) at Sep. 30, 2018		83,885
Ending balance at Sep. 30, 2018	$ (170,683)	$ 130	$ (1,725,349)	$ 1,006,121	$ 554,797	$ (6,382)