CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Non-Controlling Interest [Member]	Total
Balances at Dec. 31, 2012	$ 2	$ 181,063	$ (2,917)	$ 168,697		$ 346,845
Balances, Shares at Dec. 31, 2012	22,052,000
Net income				63,926	$ 594	64,520
Foreign currency translation adjustment			561			561
Exercise of stock options		1,524				1,524
Exercise of stock options, Shares	160,000
Stock issuance costs		(155)				(155)
Stock based compensation - options		1,429				1,429
Stock-based compensation - restricted stock		107				107
Stock-based compensation - restricted stock, Shares	28,000
Excess tax benefit from share-based compensation awards		295				295
Balances at Dec. 31, 2013	$ 2	184,263	(2,356)	232,623	594	415,126
Balances, Shares at Dec. 31, 2013	22,240,000
Net income				60,274	111	60,385
Foreign currency translation adjustment			(3,321)			(3,321)
Repurchase of common stock		(31,395)				(31,395)
Repurchase of common stock, Shares	(1,483,000)
Exercise of stock options		114				114
Exercise of stock options, Shares	7,000
Stock based compensation - options		1,627				1,627
Stock-based compensation - restricted stock		258				258
Stock-based compensation - restricted stock, Shares	24,000
Excess tax benefit from share-based compensation awards		27				27
Contributions and other					84	84
Balances at Dec. 31, 2014	$ 2	154,894	(5,677)	292,897	789	$ 442,905
Balances, Shares at Dec. 31, 2014	20,788,000					20,788,277
Net income				26,838	134	$ 26,972
Foreign currency translation adjustment			(2,245)			(2,245)
Repurchase of common stock		(12,997)				(12,997)
Repurchase of common stock, Shares	(1,089,000)
Exercise of stock options		4,744				4,744
Exercise of stock options, Shares	415,000
Stock based compensation - options		1,542				1,542
Stock-based compensation - restricted stock		373				373
Stock-based compensation - restricted stock, Shares	21,000
Excess tax benefit from share-based compensation awards		3				3
Payment of income tax withheld on vested restricted stock		(36)				(36)
Payment of income tax withheld on vested restricted stock, Shares	(2,000)
Balances at Dec. 31, 2015	$ 2	$ 148,523	$ (7,922)	$ 319,735	$ 923	$ 461,261
Balances, Shares at Dec. 31, 2015	20,133,000					20,132,706