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, 2018		$ 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	$ 77,696			77,696
Other comprehensive (loss) income	3,435				3,435
Dividends declared on common stock				(24,893)
Stock compensation expense			8,244
Net issuance of treasury stock for vested restricted stock units (in shares)		746
Net issuance of treasury stock for vested restricted stock units			(3,670)			(11,582)
Adoption of accounting standards updates related to credit losses in 2020 and leases in 2019				(593)
Repurchases of common stock						0
Repurchases of common stock, shares		0
Ending Balance at Jun. 30, 2019	$ 929,902	$ 1,751	280,636	2,049,995	(265,373)	(1,137,107)
Ending Balance (in shares) at Jun. 30, 2019		111,176
Increase (Decrease) in Stockholders' Equity
Dividends per share (usd per share)	$ 0.22
Beginning Balance at Mar. 31, 2019		$ 1,751	276,435	2,031,487	(272,431)	(1,137,035)
Beginning Balance (in shares) at Mar. 31, 2019		111,128
Increase (Decrease) in Stockholders' Equity
Net income	$ 30,955			30,955
Other comprehensive (loss) income	7,058				7,058
Dividends declared on common stock				(12,447)
Stock compensation expense			4,335
Net issuance of treasury stock for vested restricted stock units (in shares)		48
Net issuance of treasury stock for vested restricted stock units			(134)			(72)
Adoption of accounting standards updates related to credit losses in 2020 and leases in 2019				0
Repurchases of common stock						0
Repurchases of common stock, shares		0
Ending Balance at Jun. 30, 2019	$ 929,902	$ 1,751	280,636	2,049,995	(265,373)	(1,137,107)
Ending Balance (in shares) at Jun. 30, 2019		111,176
Increase (Decrease) in Stockholders' Equity
Dividends per share (usd per share)	$ 0.11
Beginning Balance at Dec. 31, 2019	$ 1,023,322	$ 1,751	289,422	2,141,302	(259,742)	(1,149,411)
Beginning Balance (in shares) at Dec. 31, 2019		110,780
Increase (Decrease) in Stockholders' Equity
Net income	135,772			135,772
Other comprehensive (loss) income	(37,618)				(37,618)
Dividends declared on common stock				(27,018)
Stock compensation expense			9,056
Net issuance of treasury stock for vested restricted stock units (in shares)		365
Net issuance of treasury stock for vested restricted stock units			(1,839)			(4,382)
Adoption of accounting standards updates related to credit losses in 2020 and leases in 2019				(665)
Repurchases of common stock						(6,934)
Repurchases of common stock, shares		(259)
Ending Balance at Jun. 30, 2020	$ 1,089,694	$ 1,751	296,639	2,249,391	(297,360)	(1,160,727)
Ending Balance (in shares) at Jun. 30, 2020		110,886
Increase (Decrease) in Stockholders' Equity
Dividends per share (usd per share)	$ 0.24
Beginning Balance at Mar. 31, 2020		$ 1,751	292,283	2,184,691	(297,697)	(1,160,453)
Beginning Balance (in shares) at Mar. 31, 2020		110,834
Increase (Decrease) in Stockholders' Equity
Net income	$ 78,172			78,172
Other comprehensive (loss) income	337				337
Dividends declared on common stock				(13,472)
Stock compensation expense			4,573
Net issuance of treasury stock for vested restricted stock units (in shares)		52
Net issuance of treasury stock for vested restricted stock units			(217)			(274)
Adoption of accounting standards updates related to credit losses in 2020 and leases in 2019				0
Repurchases of common stock						0
Repurchases of common stock, shares		0
Ending Balance at Jun. 30, 2020	$ 1,089,694	$ 1,751	$ 296,639	$ 2,249,391	$ (297,360)	$ (1,160,727)
Ending Balance (in shares) at Jun. 30, 2020		110,886
Increase (Decrease) in Stockholders' Equity
Dividends per share (usd per share)	$ 0.12