CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income
Balance (in shares) at Dec. 31, 2012		75,890
Balance at Dec. 31, 2012	$ 236,479	$ 758	$ 138,197	$ 94,349	$ 3,175
Repurchase of common stock (in shares)		(780)
Repurchase of common stock	(12,524)	$ (8)	(12,516)
Issuance of common stock for share-based compensation plans (in shares)		1,149
Issuance of common stock for share-based compensation plans	(5,680)	$ 14	(5,694)
Issuance of stock under Employee Stock Purchase Plan (in shares)		38
Issuance of stock under Employee Stock Purchase Plan	545		545
Issuance of stock awards (in shares)		27
Issuance of stock awards	0	$ 0	0	0	0
Stock-based compensation expense	12,869		12,869
Tax benefit from exercise or vesting of equity awards, net of deferred tax asset deficiencies	6,164		6,164
Cash dividends declared	(4,566)			(4,566)
Other comprehensive income (loss)	458				458
Net income	38,043			38,043
Balance (in shares) at Dec. 31, 2013		76,324
Balance at Dec. 31, 2013	271,788	$ 764	139,565	127,826	3,633
Repurchase of common stock (in shares)		(770)
Repurchase of common stock	(15,559)	$ (8)	(15,551)
Issuance of common stock for share-based compensation plans (in shares)		742
Issuance of common stock for share-based compensation plans	(5,695)	$ 8	(5,703)
Issuance of stock under Employee Stock Purchase Plan (in shares)		32
Issuance of stock under Employee Stock Purchase Plan	568		568
Issuance of stock awards (in shares)		29
Issuance of stock awards	0	$ 0	0	0	0
Stock-based compensation expense	19,205		19,205
Tax benefit from exercise or vesting of equity awards, net of deferred tax asset deficiencies	3,411		3,411
Cash dividends declared	(8,023)			(8,023)
Other comprehensive income (loss)	(4,245)				(4,245)
Net income	33,255			33,255
Balance (in shares) at Dec. 31, 2014		76,357
Balance at Dec. 31, 2014	294,705	$ 764	141,495	153,058	(612)
Repurchase of common stock (in shares)		(952)
Repurchase of common stock	(22,750)	$ (10)	(22,740)
Issuance of common stock for share-based compensation plans (in shares)		1,028
Issuance of common stock for share-based compensation plans	(9,190)	$ 11	(9,201)
Issuance of stock under Employee Stock Purchase Plan (in shares)		24
Issuance of stock under Employee Stock Purchase Plan	550		550
Issuance of stock awards (in shares)		31
Issuance of stock awards	0	$ 0	0	0	0
Stock-based compensation expense	30,078		30,078
Tax benefit from exercise or vesting of equity awards, net of deferred tax asset deficiencies	5,236		5,236
Cash dividends declared	(9,197)			(9,197)
Other comprehensive income (loss)	(2,895)				(2,895)
Net income	36,322			36,322
Balance (in shares) at Dec. 31, 2015		76,488
Balance at Dec. 31, 2015	$ 322,859	$ 765	$ 145,418	$ 180,183	$ (3,507)