CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (USD $) In Thousands, unless otherwise specified	Total	Common Stock Issued	Common Stock in Treasury	Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning balance at Dec. 31, 2011	$ 229,989	$ 211	$ (98,877)	$ 173,701	$ 938	$ 154,016
Beginning balance (in shares) at Dec. 31, 2011		21,143	6,353
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	16,553					16,553
Currency translation adjustment	114				114
Shares issued for employee benefit plan and compensation (in shares)		159
Shares issued for employee benefit plan and compensation	749	2		747
Purchase of treasury shares (in shares)	(201)		(201)
Purchase of treasury shares	(3,451)		(3,451)
Stock options exercised (in shares)	189	189
Stock options exercised	2,204	2		2,202
Shares Issued to Directors (in shares)			38
Shares issued to Directors	0		535	(535)
Stock-based compensation expense	4,575			4,575
Tax benefit from exercise of non-qualified stock options and vested restricted stock	(83)			(83)
Ending balance at Dec. 31, 2012	250,650	215	(101,793)	180,607	1,052	170,569
Ending balance (in shares) at Dec. 31, 2012		21,491	6,516
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	22,963					22,963
Currency translation adjustment	1,930				1,930
Shares issued for employee benefit plan and compensation (in shares)		174
Shares issued for employee benefit plan and compensation	747	1		746
Purchase of treasury shares (in shares)	(153)		(153)
Purchase of treasury shares	(3,607)		(3,607)
Stock options exercised (in shares)	679	679
Stock options exercised	12,371	7		12,364
Shares Issued to Directors (in shares)			30
Shares issued to Directors	0		420	(420)
Stock-based compensation expense	5,342			5,342
Tax benefit from exercise of non-qualified stock options and vested restricted stock	874			874
Ending balance at Dec. 31, 2013	291,270	223	(104,980)	199,513	2,982	193,532
Ending balance (in shares) at Dec. 31, 2013		22,344	6,639
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	32,534					32,534
Currency translation adjustment	(7,428)				(7,428)
Shares issued for employee benefit plan and compensation (in shares)		160
Shares issued for employee benefit plan and compensation	847	2		845
Purchase of treasury shares (in shares)	(384)		(384)
Purchase of treasury shares	(16,168)		(16,168)
Stock options exercised (in shares)	391	391
Stock options exercised	8,122	4		8,118
Shares Issued to Directors (in shares)		15	15
Shares issued to Directors	0	0	210	(210)
Stock-based compensation expense	6,444			6,444
Ending balance at Dec. 31, 2014	$ 315,621	$ 229	$ (120,938)	$ 214,710	$ (4,446)	$ 226,066
Ending balance (in shares) at Dec. 31, 2014		22,910	7,008