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, 2015			60,393,000
Beginning Balance at Dec. 31, 2015		$ 639,184	$ 876	$ 237,291	$ 1,446,193	$ (208,806)	$ (836,370)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		153,351			153,351
Other comprehensive income (loss)		(15,050)				(15,050)
Dividends declared on common stock (a)	[1]	(40,877)			(40,877)
Stock compensation expense		13,018		13,018
Net issuance of treasury stock for vested restricted stock units (in shares)			114,000
Net issuance of treasury stock for vested restricted stock units		(3,430)		(1,144)			(2,286)
Repurchases of common stock (in shares)			(5,456,000)
Repurchases of common stock		(277,306)					(277,306)
Adoption of accounting standards update related to stock compensation accounting		525		598	(73)
Ending Balance at Dec. 31, 2016		469,415	$ 876	249,763	1,558,594	(223,856)	(1,115,962)
Ending Balance (in shares) at Dec. 31, 2016			55,051,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		269,659			269,659
Other comprehensive income (loss)		56,968				56,968
Dividends declared on common stock (a)		(40,493)			(40,493)
Stock compensation expense		14,639		14,639
Net issuance of treasury stock for vested restricted stock units (in shares)			192,000
Net issuance of treasury stock for vested restricted stock units		(4,123)		(1,326)			(2,797)
Two-for-one stock split (in shares)			55,142,000
Two-for-one stock split		0	$ 875	(875)
Adoption of accounting standards update related to reclassification of certain tax effects		(22,085)			22,085	(22,085)
Ending Balance at Dec. 31, 2017		$ 766,065	$ 1,751	262,201	1,809,845	(188,973)	(1,118,759)
Ending Balance (in shares) at Dec. 31, 2017		110,385,344	110,385,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		$ 223,994			223,994
Other comprehensive income (loss)		(79,835)				(79,835)
Dividends declared on common stock (a)		(45,115)			(45,115)
Stock compensation expense		14,923		14,923
Net issuance of treasury stock for vested restricted stock units (in shares)			233,000
Net issuance of treasury stock for vested restricted stock units		(3,057)		(1,062)			(1,995)
Repurchases of common stock (in shares)			(188,000)
Repurchases of common stock		(4,771)					(4,771)
Adoption of accounting standards update related to revenue recognition		9,061			9,061
Ending Balance at Dec. 31, 2018		$ 881,265	$ 1,751	$ 276,062	$ 1,997,785	$ (268,808)	$ (1,125,525)
Ending Balance (in shares) at Dec. 31, 2018		110,429,596	110,430,000

[1] (a) Per share amounts for 2016 have been retroactively adjusted for the two-for-one stock split discussed in Note 1.