Condensed Consolidated Statement of Stockholders' Equity (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance, Value at Dec. 31, 2012	$ 362,155	$ 3,709	$ (76)	$ 164,346	$ 201,094	$ (6,918)
Beginning Balance, Issued Shares at Dec. 31, 2012	37,131,777	37,131,777
Beginning Balance, Treasury Shares at Dec. 31, 2012			(40,509)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	44,029				44,029
Cumulative translation adjustment	(2,426)					(2,426)
Repurchase and retirement of common stock, Shares		250,900
Repurchase and retirement of common stock, Value	2,492	25		2,467
Vesting of restricted stock, Shares		64,035
Vesting of restricted stock, Value	0	7		(7)
Exercise of stock options, Shares		1,150,380
Exercise of stock options, Value	1,425	115		1,310
Share based compensation	1,481			1,481
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested, Shares	(66,000)	(65,762)
Forfeiture of certain shares to satisfy exercise costs and the recipients income tax obligations related to stock options exercised and restricted stock vested	(916)	(7)		(909)
Dividends paid	(2,794)				(2,794)
Ending Balance, Value at Sep. 30, 2013	$ 400,462	$ 3,799	$ (76)	$ 163,754	$ 242,329	$ (9,344)
Ending Balance, Issued Shares at Sep. 30, 2013	38,029,530	38,029,530
Ending Balance, Treasury Shares at Sep. 30, 2013			(40,509)