Consolidated Statements of Stockholders' Equity (Deficit) (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	117,698				114,843	2,855
Purchase of treasury stock (in shares)		(7,926)
Purchase of treasury stock	(229,169)		(229,169)
Dividends declared	(28,196)				(28,196)
Exercise of stock options (in shares)		21
Exercise of stock options	305	$ 0		305
Restricted stock awards (in shares)		33
Restricted stock awards	0
Minimum tax withholding requirements (in shares)		(22)
Minimum tax withholding requirements	(622)			(622)
Net excess tax benefits from stock-based compensation	(281)			(281)
Stock-based compensation	2,949			2,949
Ending balance (in shares) at Jun. 30, 2016		68,382
Ending balance at Jun. 30, 2016	331,245	$ 114	(1,725,349)	918,479	1,144,795	(6,794)
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	41,111				39,511	1,600
Dividend forfeitures on restricted stock	259				259
Restricted stock awards (in shares)		101
Restricted stock awards	0
Minimum tax withholding requirements (in shares)		(32)
Minimum tax withholding requirements	(247)			(247)
Stock-based compensation	2,709			2,709
Ending balance (in shares) at Jun. 30, 2017		68,468
Ending balance at Jun. 30, 2017	$ (51,215)	$ 114	$ (1,725,349)	$ 925,149	$ 755,968	$ (7,097)