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, 2017	$ 766,065	$ 1,751	$ 262,201	$ 1,809,845	$ (188,973)	$ (1,118,759)
Beginning Balance (in shares) at Dec. 31, 2017		110,385
Increase (Decrease) in Stockholders' Equity
Net income	45,721			45,721
Other comprehensive (loss) income	14,266				14,266
Dividends declared on common stock	$ (11,276)			(11,276)
Dividends per share (usd per share)	$ 0.10
Stock compensation expense	$ 3,700		3,700
Net issuance of treasury stock for vested restricted stock units (in shares)		184
Net issuance of treasury stock for vested restricted stock units	(2,746)		(879)			(1,867)
Adoption of accounting standards update related to revenue recognition	9,061			9,061
Ending Balance at Mar. 31, 2018	824,791	$ 1,751	265,022	1,853,351	(174,707)	(1,120,626)
Ending Balance (in shares) at Mar. 31, 2018		110,569
Beginning Balance at Dec. 31, 2018	881,265	$ 1,751	276,062	1,997,785	(268,808)	(1,125,525)
Beginning Balance (in shares) at Dec. 31, 2018		110,430
Increase (Decrease) in Stockholders' Equity
Net income	46,742			46,742
Other comprehensive (loss) income	(3,623)				(3,623)
Dividends declared on common stock	$ (12,447)			(12,447)
Dividends per share (usd per share)	$ 0.11
Stock compensation expense	$ 3,909		3,909
Net issuance of treasury stock for vested restricted stock units (in shares)		698
Net issuance of treasury stock for vested restricted stock units	(15,046)		(3,536)			(11,510)
Adoption of accounting standards update related to leases	(593)			(593)
Ending Balance at Mar. 31, 2019	$ 900,207	$ 1,751	$ 276,435	$ 2,031,487	$ (272,431)	$ (1,137,035)
Ending Balance (in shares) at Mar. 31, 2019		111,128