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	53,170				53,170
Cumulative translation adjustment and foreign currency exchange hedge, net of tax	(492)					(492)
Unrealized net loss on securities available-for-sale, net of tax	(5)					(5)
Stock-based compensation	7,179		7,179
Exercise of stock options	1,390	1	1,389
Withholding tax payments on restricted stock vesting and stock option exercises	(5,008)		(5,008)
Excess tax benefits from stock-based compensation	3,203		3,203
Repurchases of common stock	(25,442)			(25,442)
Cash dividend on common stock	(18,054)				(18,054)
Ending Balance at Sep. 30, 2014	$ 326,303	$ 120	$ 302,320	$ (57,715)	$ 86,158	$ (4,580)