CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Common Stock Held in Treasury
Balance at beginning of period (shares) at Dec. 31, 2016		49,276				769
Balance at beginning of period (value) at Dec. 31, 2016	$ 1,449,986	$ 493	$ 1,217,969	$ 387,401	$ (119,806)	$ (36,071)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under share-based compensation (shares)		0				(10)
Shares issued under share-based compensation (value)	0	$ 0	(440)			$ 440
Exercise of stock options, net of shares net-settled (shares)		0				(13)
Exercise of stock options, net of shares net-settled (value)	307	$ 0	(242)			$ 549
Share-based compensation expense (value)	3,069		3,069
Net income	143,892			143,892
Dividends paid	(36,836)			(36,836)
Currency translation adjustment	7,929				7,929
Repurchases of treasury stock (shares)						1,616
Repurchases of treasury stock (value)	(93,014)					$ (93,014)
Balance at end of period (shares) at Dec. 31, 2017		49,276				2,362
Balance at end of period (value) at Dec. 31, 2017	1,475,333	$ 493	1,220,356	494,457	(111,877)	$ (128,096)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under share-based compensation (shares)		0				(22)
Shares issued under share-based compensation (value)	0	$ 0	(1,240)			$ 1,240
Exercise of stock options, net of shares net-settled (shares)						(10)
Exercise of stock options, net of shares net-settled (value)	400		(294)			$ 694
Share-based compensation expense (value)	5,786		5,786
Net income	153,206			153,206
Dividends paid	(40,853)			(40,853)
Currency translation adjustment	(1,240)				(1,240)
Repurchases of treasury stock (shares)						3,343
Repurchases of treasury stock (value)	(274,528)					$ (274,528)
Balance at end of period (shares) at Dec. 31, 2018		49,276				5,673
Balance at end of period (value) at Dec. 31, 2018	1,318,104	$ 493	1,224,608	606,810	(113,117)	$ (400,690)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under share-based compensation (shares)						(21)
Shares issued under share-based compensation (value)	0		(1,441)			$ 1,441
Exercise of stock options, net of shares net-settled (shares)						(10)
Exercise of stock options, net of shares net-settled (value)	400		(319)			$ 719
Share-based compensation expense (value)	8,680		8,680
Net income	164,618			164,618
Dividends paid	(43,952)			(43,952)
Currency translation adjustment	16,148				16,148
Repurchases of treasury stock (shares)						1,305
Repurchases of treasury stock (value)	(113,963)					$ (113,963)
Balance at end of period (shares) at Dec. 31, 2019		49,276				6,947
Balance at end of period (value) at Dec. 31, 2019	$ 1,350,035	$ 493	$ 1,231,528	$ 727,476	$ (96,969)	$ (512,493)