Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]
Beginning Balance (in shares) at Dec. 31, 2012		69,204,000
Beginning Balance at Dec. 31, 2012	$ 753,643	$ 876	$ 204,449	$ 1,020,543	$ (109,913)	$ (362,312)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	185,413			185,413
Other comprehensive income (loss)	71,794				71,794
Dividends declared on common stock	(36,202)			(36,202)
Stock compensation expense	8,902		8,902
Net issuance of treasury stock for vested restricted stock units (in shares)		90,000
Net issuance of treasury stock for vested restricted stock units, including tax benefit	(2,100)		(529)			(1,571)
Repurchases of common stock (in shares)		(5,879,000)
Repurchases of common stock	(267,607)					(267,607)
Ending Balance (in shares) at Dec. 31, 2013		63,415,000
Ending Balance at Dec. 31, 2013	713,843	$ 876	212,822	1,169,754	(38,119)	(631,490)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	182,391			182,391
Other comprehensive income (loss)	(127,505)				(127,505)
Dividends declared on common stock	(38,624)			(38,624)
Stock compensation expense	12,718		12,718
Net issuance of treasury stock for vested restricted stock units (in shares)		297,000
Net issuance of treasury stock for vested restricted stock units, including tax benefit	(8,201)		(91)			(8,110)
Repurchases of common stock (in shares)		(509,000)
Repurchases of common stock	$ (24,666)					(24,666)
Ending Balance (in shares) at Dec. 31, 2014	63,203,361	63,203,000
Ending Balance at Dec. 31, 2014	$ 709,956	$ 876	225,449	1,313,521	(165,624)	(664,266)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	172,413			172,413
Other comprehensive income (loss)	(43,182)				(43,182)
Dividends declared on common stock	(39,741)			(39,741)
Stock compensation expense	12,403		12,403
Net issuance of treasury stock for vested restricted stock units (in shares)		96,000
Net issuance of treasury stock for vested restricted stock units, including tax benefit	(2,533)		(561)			(1,972)
Repurchases of common stock (in shares)		(2,906,000)
Repurchases of common stock	$ (170,132)					(170,132)
Ending Balance (in shares) at Dec. 31, 2015	60,392,905	60,393,000
Ending Balance at Dec. 31, 2015	$ 639,184	$ 876	$ 237,291	$ 1,446,193	$ (208,806)	$ (836,370)