CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Stock	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, 2012		0	38,796				9,700
Balance at beginning of period (value) at Dec. 31, 2012	$ 352,416	$ 0	$ 388	$ 159,081	$ 413,882	$ (6,940)	$ (213,995)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under share-based compensation (shares)			8
Shares issued under share-based compensation (value)	0		$ 0
Exercise of stock options, net of shares net-settled (shares)			573
Exercise of stock options, net of shares net-settled (value)	9,242		$ 6	9,236
Income tax benefit from exercise of stock options and warrants (value)	7,805			7,805
Share-based compensation expense (value)	553			553
Net income	83,846				83,846
Currency translation adjustment	(4,821)					(4,821)
Repurchases of treasury stock (shares)							729
Repurchases of treasury stock (value)	(38,692)						$ (38,692)
Balance at end of period (shares) at Dec. 31, 2013		0	39,377				10,429
Balance at end of period (value) at Dec. 31, 2013	410,349	$ 0	$ 394	176,675	497,728	(11,761)	$ (252,687)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under share-based compensation (shares)			37
Shares issued under share-based compensation (value)	0		$ 0
Exercise of stock options, net of shares net-settled (shares)			294
Exercise of stock options, net of shares net-settled (value)	5,270		$ 3	5,267
Income tax benefit from exercise of stock options and warrants (value)	4,141			4,141
Share-based compensation expense (value)	1,979			1,979
Net income	85,166				85,166
Currency translation adjustment	(28,517)					(28,517)
Repurchases of treasury stock (shares)							771
Repurchases of treasury stock (value)	(43,947)						$ (43,947)
Balance at end of period (shares) at Dec. 31, 2014		0	39,708				11,200
Balance at end of period (value) at Dec. 31, 2014	434,441	$ 0	$ 397	188,062	582,894	(40,278)	$ (296,634)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under share-based compensation (shares)			5
Shares issued under share-based compensation (value)	0		$ 0
Exercise of stock options, net of shares net-settled (shares)			575
Exercise of stock options, net of shares net-settled (value)	8,782		$ 6	8,776
Income tax benefit from exercise of stock options and warrants (value)	5,126			5,126
Share-based compensation expense (value)	429			429
Net income	60,710				60,710
Currency translation adjustment	(38,132)					(38,132)
Repurchases of treasury stock (shares)							852
Repurchases of treasury stock (value)	(39,974)						$ (39,974)
Balance at end of period (shares) at Dec. 31, 2015		0	40,288				12,052
Balance at end of period (value) at Dec. 31, 2015	$ 431,382	$ 0	$ 403	$ 202,393	$ 643,604	$ (78,410)	$ (336,608)