Condensed Consolidated Statements Of Stockholders' Equity And Comprehensive Income (USD $) In Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Comprehensive Income [Member]	Total
Balance at Dec. 31, 2010	$ 240	$ 113,412	$ 188,894	$ 151		$ 302,697
Balance, shares at Dec. 31, 2010	24,011
Net income			28,454		28,454	28,454
Other comprehensive gain:
Unrealized loss on cash flow hedge, net of tax				(29)	(29)	(29)
Exercise of stock options and issuance of share-based awards, net of shares withheld for employee taxes, shares	437
Exercise of stock options and issuance of share-based awards, net of shares withheld for employee taxes	4	(2,146)				(2,142)
Stock-based compensation		3,575				3,575
Tax benefit related to stock-based compensation		4,719				4,719
Balance at Jun. 30, 2011	$ 244	$ 119,560	$ 217,348	$ 122	$ 28,425	$ 337,274
Balance, shares at Jun. 30, 2011	24,448