Consolidated Statements of Changes in Stockholders' Equity (USD $) In Thousands	Total	Common Stock Voting [Member]	Additional Paid-in Capital [Member]	Treasury Stock - Common Stock Voting [Member]	Retained Earnings (Deficit) [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Dec. 31, 2013	$ 310,362	$ 119	$ 295,557	$ (32,273)	$ 51,042	$ (4,083)
Net income	35,666				35,666
Cumulative translation adjustment and foreign currency exchange hedge, net of tax	(381)					(381)
Unrealized net gain on securities available-for-sale, net of tax	34					34
Stock-based compensation	4,651		4,651
Exercise of stock options	845		845
Withholding tax payments on restricted stock vesting and stock option exercises	(4,968)		(4,968)
Excess tax benefits from stock-based compensation	2,576		2,576
Repurchases of common stock	(13,748)			(13,748)
Cash dividend on common stock	(12,058)				(12,058)
Ending Balance at Jun. 30, 2014	$ 322,979	$ 119	$ 298,661	$ (46,021)	$ 74,650	$ (4,430)