Condensed Consolidated Statements Of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning Balance at Dec. 31, 2014	$ 709,956	$ 876	$ 225,449	$ 1,313,521	$ (165,624)	$ (664,266)
Beginning Balance (in shares) at Dec. 31, 2014		63,203
Increase (Decrease) in Stockholders' Equity
Net issuance of treasury stock for vested restricted stock units, including tax benefit (in shares)		96
Repurchases of common stock (in shares)		(2,906)
Net income	145,866			145,866
Other comprehensive income (loss)	(31,254)				(31,254)
Dividends declared on common stock	(29,919)			(29,919)
Stock compensation expense	9,580		9,580
Net issuance of treasury stock for vested restricted stock units, including tax benefit	(2,212)		(240)			(1,972)
Repurchases of common stock	(170,132)					(170,132)
Ending Balance at Sep. 30, 2015	631,885	$ 876	234,789	1,429,468	(196,878)	(836,370)
Ending Balance (in shares) at Sep. 30, 2015		60,393
Beginning Balance at Dec. 31, 2015	639,184	$ 876	237,291	1,446,193	(208,806)	(836,370)
Beginning Balance (in shares) at Dec. 31, 2015		60,393
Increase (Decrease) in Stockholders' Equity
Net issuance of treasury stock for vested restricted stock units, including tax benefit (in shares)		94
Repurchases of common stock (in shares)		(147)
Net income	129,655			129,655
Other comprehensive income (loss)	13,544				13,544
Dividends declared on common stock	(31,344)			(31,344)
Stock compensation expense	9,724		9,724
Adoption of accounting standard update related to stock compensation accounting	525		598	(73)
Net issuance of treasury stock for vested restricted stock units, including tax benefit	(2,434)		(892)			(1,542)
Repurchases of common stock	(7,200)					(7,200)
Ending Balance at Sep. 30, 2016	$ 751,654	$ 876	$ 246,721	$ 1,544,431	$ (195,262)	$ (845,112)
Ending Balance (in shares) at Sep. 30, 2016		60,340