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)		82
Repurchases of common stock (in shares)		(2,906)
Net income	75,548			75,548
Other comprehensive income (loss)	(17,155)				(17,155)
Dividends declared on common stock	(20,113)			(20,113)
Stock compensation expense	6,689		6,689
Net issuance of treasury stock for vested restricted stock units, including tax benefit	(1,767)		(21)			(1,746)
Repurchases of common stock	(170,132)					(170,132)
Ending Balance at Jun. 30, 2015	583,026	$ 876	232,117	1,368,956	(182,779)	(836,144)
Ending Balance (in shares) at Jun. 30, 2015		60,379
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)		84
Repurchases of common stock (in shares)		0
Net income	59,886			59,886
Other comprehensive income (loss)	6,510				6,510
Dividends declared on common stock	(20,913)			(20,913)
Stock compensation expense	6,428		6,428
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	(2,204)		(802)			(1,402)
Repurchases of common stock	(10)					(10)
Ending Balance at Jun. 30, 2016	$ 689,406	$ 876	$ 243,515	$ 1,485,093	$ (202,296)	$ (837,782)
Ending Balance (in shares) at Jun. 30, 2016		60,477