Consolidated Statements Of Stockholders' Equity (USD $) In Thousands, unless otherwise specified	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Stockholder Notes Receivable [Member]	Accumulated Other Comprehensive Loss [Member]	Total
Balance at Dec. 31, 2008	$ 15	$ 120,550	$ 84,110	$ (1,474)	$ (12)	$ (272)	$ 202,917
Balance, shares at Dec. 31, 2008	15,107			82
Net income			22,356				22,356
Other Comprehensive Income
Foreign currency translation adjustment						(65)	(65)
Total Comprehensive Income							22,291
Issuance of shares pursuant to secondary offering	4	83,290					83,294
Issuance of shares pursuant to secondary offering, shares	3,565
Equity compensation		7,192					7,192
Exercise of stock options		1,093		1,739			2,832
Exercise of stock options, shares	337			93
Issuance of shares pursuant to vesting of restricted stock units		(3,914)		3,914
Issuance of shares pursuant to vesting of restricted stock units, shares	409			141
Net payments for stockholder issuances and buybacks		88		(4,179)			(4,091)
Net payments for stockholder issuances and buybacks, shares	(139)			152
Tax impact of stock option exercises and award vesting		3,113					3,113
Proceeds on stockholder notes					12		12
Balance at Dec. 31, 2009	19	211,412	106,466			(337)	317,560
Balance, shares at Dec. 31, 2009	19,279
Net income			27,171				27,171
Other Comprehensive Income
Foreign currency translation adjustment						(187)	(187)
Total Comprehensive Income							26,984
Equity compensation		7,533					7,533
Exercise of stock options		966					966
Exercise of stock options, shares	110
Issuance of shares pursuant to vesting of restricted stock units	1						1
Issuance of shares pursuant to vesting of restricted stock units, shares	207
Net payments for stockholder issuances and buybacks		66		(1,291)			(1,225)
Net payments for stockholder issuances and buybacks, shares	(28)			51
Tax impact of stock option exercises and award vesting		914					914
Balance at Dec. 31, 2010	20	220,891	133,637	(1,291)		(524)	352,733
Balance, shares at Dec. 31, 2010	19,568			51
Net income			34,865				34,865
Other Comprehensive Income
Foreign currency translation adjustment						(281)	(281)
Total Comprehensive Income							34,584
Equity compensation		6,658					6,658
Exercise of stock options		478					478
Exercise of stock options, shares	39
Issuance of shares pursuant to vesting of restricted stock units
Issuance of shares pursuant to vesting of restricted stock units, shares	176
Net payments for stockholder issuances and buybacks		77		(975)			(898)
Net payments for stockholder issuances and buybacks, shares	9			44
Tax impact of stock option exercises and award vesting		(527)					(527)
Balance at Dec. 31, 2011	$ 20	$ 227,577	$ 168,502	$ (2,266)		$ (805)	$ 393,028
Balance, shares at Dec. 31, 2011	19,792			95