Consolidated Statements Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance, Issued Shares at Dec. 31, 2012		37,131,777
Beginning Balance, Treasury Shares at Dec. 31, 2012			(40,509)
Beginning Balance, Value at Dec. 31, 2012	$ 362,155	$ 3,709	$ (76)	$ 164,346	$ 201,094	$ (6,918)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	59,274				59,274
Cumulative translation adjustment	(5,376)					(5,376)
Exercise of stock options, Shares		1,251,633
Exercise of stock options	2,161	$ 125		2,036
Deferred compensation and amortization related to options and restricted stock	1,941			1,941
Repurchase of common stock, Shares		(250,900)
Repurchase of common stock	(2,492)	$ (25)		(2,467)
APIC adjustment for stock options	37			37
Vesting of restricted stock, Shares		76,576
Vesting of restricted stock	0	$ 8		(8)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested, Shares		(120,695)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested	(1,681)	$ (12)		(1,669)
Dividends paid	(2,794)				(2,794)
Ending Balance, Issued Shares at Dec. 31, 2013		38,088,391
Ending Balance, Treasury Shares at Dec. 31, 2013			(40,509)
Ending Balance, Value at Dec. 31, 2013	413,225	$ 3,805	$ (76)	164,216	257,574	(12,294)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	63,558				63,558
Cumulative translation adjustment	(5,855)					(5,855)
Exercise of stock options, Shares		450,000
Exercise of stock options	788	$ 45		743
Deferred compensation and amortization related to options and restricted stock	1,792			1,792
Repurchase of common stock, Shares		(2,146,488)
Repurchase of common stock	(31,854)	$ (215)		(31,639)
Vesting of restricted stock, Shares		52,384
Vesting of restricted stock	0	$ 5		(5)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested, Shares		(2,557)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested	(41)	$ 0		(41)
Shares reaquired in connection with put option, Shares		(209,656)
Shares reacquired in connection with put option	(2,986)	$ (21)		(2,965)
Reclassification of shares previously reported as temporary equity in connection with an acquisition, Value	5,000			5,000
Dividends paid	$ (11,406)				(11,406)
Ending Balance, Issued Shares at Dec. 31, 2014	36,232,074	36,232,074
Ending Balance, Treasury Shares at Dec. 31, 2014			(40,509)
Ending Balance, Value at Dec. 31, 2014	$ 432,221	$ 3,619	$ (76)	137,101	309,726	(18,149)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	79,533				79,533
Cumulative translation adjustment	(12,129)					(12,129)
Exercise of stock options, Shares		109,122
Exercise of stock options	2,209	$ 11		2,198
Deferred compensation and amortization related to options and restricted stock	$ 1,821			1,821
Repurchase of common stock, Shares	(2,924,306)	(2,924,306)
Repurchase of common stock	$ (82,473)	$ (293)		(82,180)
APIC adjustment for stock options	463			463
Vesting of restricted stock, Shares		108,797
Vesting of restricted stock	$ 0	$ 12		(12)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested, Shares	(69,068)	(69,068)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested	$ (2,202)	$ (7)		(2,195)
Cancellation of treasury shares, shares		(40,509)	40,509
Cancellation of treasury shares	0		$ 76	(76)
Dividends paid	$ (10,472)				(10,472)
Ending Balance, Issued Shares at Dec. 31, 2015	33,416,110	33,416,110
Ending Balance, Treasury Shares at Dec. 31, 2015			0
Ending Balance, Value at Dec. 31, 2015	$ 408,971	$ 3,342	$ 0	$ 57,120	$ 378,787	$ (30,278)