Consolidated Statement of Changes in Stockholders' Equity - 3 months ended Mar. 31, 2016 - 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, 2015	$ 390,713	$ 121	$ 321,215	$ (93,405)	$ 168,011	$ (5,229)
Net income	28,963				28,963
Cumulative translation adjustment and foreign currency exchange hedge, net of tax	(2,237)					(2,237)
Unrealized gain on securities available-for-sale, net of tax	187					187
Stock-based compensation	3,494		3,494
Exercise of stock options	831		831
Withholding tax payments on restricted stock vesting and stock option exercises	(5,230)		(5,230)
Excess tax benefits from stock-based compensation	4,640		4,640
Repurchases of common stock	(1,199)			(1,199)
Cash dividend on common stock	(9,746)				(9,746)
Ending Balance at Mar. 31, 2016	$ 410,416	$ 121	$ 324,950	$ (94,604)	$ 187,228	$ (7,279)