Consolidated Statements of Stockholders' 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, 2014		88,335
Beginning balance at Dec. 31, 2014	$ 756,043	$ 113	$ (1,016,381)	$ 877,566	$ 898,574	$ (3,829)
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)	57,959				63,270	(5,311)
Purchase of treasury stock (in shares)		(1,394)
Purchase of treasury stock	(62,342)		(62,342)
Dividends declared	(15,797)				(15,797)
Exercise of stock options (in shares)		41
Exercise of stock options	897	$ 1		896
Restricted stock awards (in shares)		210
Minimum tax withholding requirements (in shares)		(5)
Minimum tax withholding requirements	(216)			(216)
Net excess tax benefits from stock-based compensation	320			320
Excess tax benefits from stock-based compensation (in shares)		0
Stock-based compensation	1,305			1,305
Ending balance (in shares) at Mar. 31, 2015		87,187
Ending balance at Mar. 31, 2015	738,169	$ 114	(1,078,723)	879,871	946,047	(9,140)
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 (loss)	53,740				50,815	2,925
Purchase of treasury stock (in shares)		(7,599)
Purchase of treasury stock	(218,941)		(218,941)
Dividends declared	(14,413)				(14,413)
Exercise of stock options (in shares)		20
Exercise of stock options	292			292
Restricted stock awards (in shares)		16
Minimum tax withholding requirements (in shares)		(19)
Minimum tax withholding requirements	(519)			(519)
Net excess tax benefits from stock-based compensation	(315)			(315)
Stock-based compensation	1,419			1,419
Ending balance (in shares) at Mar. 31, 2016		68,694
Ending balance at Mar. 31, 2016	$ 289,824	$ 114	$ (1,715,121)	$ 917,005	$ 1,094,550	$ (6,724)