Consolidated Statements of Shareholders' Equity Statement - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]
Common Stock, Shares, Outstanding	46,924,238	46,924,000
Stockholders' Equity Attributable to Parent	$ 771,891	$ 469	$ 590,163	$ 179,968	$ 1,291
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		414,000
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	0	$ 4	(4)
Stock Issued During Period, Shares, Employee Stock Purchase Plans		51,000
Stock Issued During Period, Value, Employee Stock Purchase Plan	1,677	$ 1	1,676
Stock Repurchased and Retired During Period, Shares		(140,000)
Stock Repurchased and Retired During Period, Value	(6,932)	$ (2)	(6,930)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	9,765		9,765
Net income	19,862			19,862
Other Comprehensive Income (Loss), Net of Tax	(187)
Common Stock, Shares, Outstanding		47,169,000
Stockholders' Equity Attributable to Parent	776,621	$ 472	587,788	187,447	914
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		32,000
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	0
Stock Issued During Period, Shares, Employee Stock Purchase Plans		51,000
Stock Issued During Period, Value, Employee Stock Purchase Plan	1,677	$ 1	1,676
Stock Repurchased and Retired During Period, Shares		(3,000)
Stock Repurchased and Retired During Period, Value	(120)	$ (1)	(119)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	5,325		5,325
Net income	12,383			12,383
Other Comprehensive Income (Loss), Net of Tax	190				190
Common Stock, Shares, Outstanding		47,249,000
Stockholders' Equity Attributable to Parent	796,076	$ 472	594,670	199,830	1,104
Common Stock, Shares, Outstanding		54,248,000
Stockholders' Equity Attributable to Parent	1,284,739	$ 542	1,058,745	226,743	(1,291)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		491,000
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures		$ 5	(2)
Stock Issued During Period, Value, Employee Stock Purchase Plan	3
Stock Repurchased and Retired During Period, Shares		(181,000)
Stock Repurchased and Retired During Period, Value	(14,937)	$ (2)	(14,935)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	12,430		12,430
Net income	34,923			34,923
Other Comprehensive Income (Loss), Net of Tax	(102)				(102)
Common Stock, Shares, Outstanding		54,534,000
Stockholders' Equity Attributable to Parent	1,295,278	$ 545	1,049,952	245,990	(1,209)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		29,000
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	0
Stock Repurchased and Retired During Period, Shares		(5,000)
Stock Repurchased and Retired During Period, Value	(375)		(375)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	6,661		6,661
Net income	15,676			15,676
Other Comprehensive Income (Loss), Net of Tax	$ (184)				(184)
Common Stock, Shares, Outstanding	47,265,355	54,558,000
Stockholders' Equity Attributable to Parent	$ 1,317,056	$ 545	$ 1,056,238	$ 261,666	$ (1,393)