Consolidated Statement of Shareholders' Equity Statement - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]
Beginning Balance, Shares		27,788,000
Beginning balance	$ 535,322	$ 278	$ 172,771	$ 367,021	$ (4,748)
Issuance of common stock under employee stock plans (in shares)		116,000
Stock Issued During Period, Value, Stock Options Exercised	4,680	$ 1	4,679
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures (in shares)		278,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	0	$ 3	(3)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	14,458		14,458
Shares Paid for Tax Withholding for Share Based Compensation (in shares)		(59,000)
Stock Withheld to Cover Tax Withholding Requirements Upon Vesting to Restricted Stock Units Amount	(7,277)	$ (1)	(7,276)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	2,632		2,632
Adjustments to Additional Paid in Capital Directors Deferred Compensation	34		34
Net income	29,727			29,727
Beginning Balance, Shares		28,038,000
Beginning balance	$ 562,623	$ 280	175,000	389,541	(2,198)
Issuance of common stock under employee stock plans (in shares)	2,117,000	39,000
Stock Issued During Period, Value, Stock Options Exercised		$ 0	2,117
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures (in shares)		47,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	$ 0	$ 1	(1)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	7,594		7,594
Shares Paid for Tax Withholding for Share Based Compensation (in shares)		(1,000)
Stock Withheld to Cover Tax Withholding Requirements Upon Vesting to Restricted Stock Units Amount	(65)	$ 0	(65)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	82
Adjustments to Additional Paid in Capital Directors Deferred Compensation	18		18
Net income	7,207			7,207
Beginning Balance, Shares		28,123,000
Beginning balance	$ 579,576	$ 281	184,663	396,748	(2,116)
Beginning Balance, Shares	28,352,000	28,352,000
Beginning balance	$ 652,069	$ 284	196,455	452,321	3,009
Stock Repurchased and Retired During Period, Shares	(663,602)
Stock Repurchased and Retired During Period, Value	$ (25,000)
Issuance of common stock under employee stock plans (in shares)		112,000
Stock Issued During Period, Value, Stock Options Exercised	3,690	$ 1	3,689
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures (in shares)		243,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	0	$ 2	(2)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	11,061		11,061
Shares Paid for Tax Withholding for Share Based Compensation (in shares)		(45,000)
Stock Withheld to Cover Tax Withholding Requirements Upon Vesting to Restricted Stock Units Amount	(1,816)	$ 0	(1,816)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1,535				1,535
Adjustments to Additional Paid in Capital Directors Deferred Compensation	42		42
Net income	$ 40,481			40,481
Stock Repurchased and Retired During Period, Shares	(664,000)
Stock Repurchased and Retired During Period, Value	$ (25,000)	$ (7)	(24,993)
Beginning Balance, Shares		27,876,000
Beginning balance	616,539	$ 279	175,790	434,186	6,284
Issuance of common stock under employee stock plans (in shares)		72,000
Stock Issued During Period, Value, Stock Options Exercised	2,756	$ 1	2,755
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures (in shares)		50,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	0	$ 0	0
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	5,870		5,870
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(1,740)				(1,740)
Adjustments to Additional Paid in Capital Directors Deferred Compensation	21		21
Net income	$ 58,616			58,616
Beginning Balance, Shares	27,998,000	27,998,000
Beginning balance	$ 682,062	$ 280	$ 184,436	$ 492,802	$ 4,544