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	52,883			52,883
Cumulative translation adjustment and foreign currency exchange hedge, net of tax	(341)				(341)
Unrealized net (loss) on securities available-for-sale, net of tax	(497)				(497)
Stock-based compensation	6,419	6,419
Exercise of stock options	1,816	1,815				1
Withholding tax payments on restricted stock vesting and stock option exercises	(5,001)	(5,001)
Excess tax benefits from stock-based compensation	3,069	3,069
Cash dividend on common stock	(14,445)			(14,445)
Balance at Sep. 30, 2013	$ 286,620	$ 289,911	$ (32,273)	$ 32,794	$ (3,931)	$ 119