CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN 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, 2014		0	39,708				11,200
Balance at beginning 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 plan (shares)			5
Shares issued under share-based compensation plan (value)	0		$ 0
Exercise of stock options (shares)			145
Exercise of stock options (value)	2,901		$ 2	2,899
Income tax benefit from exercise of stock options and warrants (value)	1,617			1,617
Share-based compensation expense (value)	700			700
Net income	16,788				16,788
Currency translation adjustment	(6,999)					(6,999)
Repurchases of treasury stock (shares)							336
Repurchases of treasury stock (value)	(16,974)						$ (16,974)
Balance at end of period (shares) at Mar. 31, 2015		0	39,858				11,536
Balance at end of period (value) at Mar. 31, 2015	432,474	$ 0	$ 399	193,278	599,682	(47,277)	$ (313,608)
Balance at beginning of period (shares) at Dec. 31, 2015		0	40,288				12,052
Balance at beginning of period (value) at Dec. 31, 2015	431,382	$ 0	$ 403	202,393	643,604	(78,410)	$ (336,608)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under share-based compensation plan (shares)			7
Shares issued under share-based compensation plan (value)	0		$ 0
Share-based compensation expense (value)	750			750
Net income	13,174				13,174
Dividends paid	(3,530)				(3,530)
Currency translation adjustment	(2,489)					(2,489)
Balance at end of period (shares) at Mar. 31, 2016		0	40,295				12,052
Balance at end of period (value) at Mar. 31, 2016	$ 439,287	$ 0	$ 403	$ 203,143	$ 653,248	$ (80,899)	$ (336,608)