Consolidated Statements of Changes in Stockholders' Equity (USD $) In Thousands	Total	Additional Paid-In Capital [Member]	Treasury Stock - Common Stock Voting [Member]	Retained (Deficit) Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Common Stock Voting [Member]
Balance at Dec. 31, 2012	$ 242,717	$ 283,609	$ (32,273)	$ (5,644)	$ (3,093)	$ 118
Net income	34,669			34,669
Cumulative translation adjustment and foreign currency exchange hedge, net of tax	43				43
Unrealized net (loss) on securities available-for-sale, net of tax	(515)				(515)
Stock-based compensation	4,178	4,178
Exercise of stock options	1,380	1,379				1
Withholding tax payments on restricted stock vesting and stock option exercises	(5,001)	(5,001)
Excess tax benefits from stock-based compensation	2,651	2,651
Cash dividend on common stock	(9,558)			(9,558)
Balance at Jun. 30, 2013	$ 270,564	$ 286,816	$ (32,273)	$ 19,467	$ (3,565)	$ 119