Consolidated Statements of Stockholders' (Deficit) Equity (unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock	Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2015		76,276
Beginning balance at Dec. 31, 2015	$ 468,561	$ 114	$ (1,496,180)	$ 916,128	$ 1,058,148	$ (9,649)
Increase (Decrease) in Stockholders' Equity
Comprehensive income	149,460				147,197	2,263
Purchase of treasury stock (in shares)		(7,926)
Purchase of treasury stock	(229,169)		(229,169)
Dividends declared	(41,939)				(41,939)
Exercise of stock options (in shares)		23
Exercise of stock options	343	$ 0		343
Restricted stock awards (in shares)		72
Restricted stock awards	0			0
Minimum tax withholding requirements (in shares)		(47)
Minimum tax withholding requirements	(1,126)			(1,126)
Net excess tax benefits from stock-based compensation	(742)			(742)
Stock-based compensation	7,191			7,191
Ending balance (in shares) at Sep. 30, 2016		68,398
Ending balance at Sep. 30, 2016	352,579	$ 114	(1,725,349)	921,794	1,163,406	(7,386)
Beginning balance (in shares) at Dec. 31, 2016		68,399
Beginning balance at Dec. 31, 2016	(95,047)	$ 114	(1,725,349)	922,687	716,198	(8,697)
Increase (Decrease) in Stockholders' Equity
Comprehensive income	64,279				60,974	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	$ (24,709)	$ 115	$ (1,725,349)	$ 928,460	$ 777,457	$ (5,392)