Employee Benefit Plan (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Employee Benefit Plan [Abstract]
Defined Contribution Plan Requisite Service Period	90 days
Defined Contribution Plan Minimum Hours of Service	1000 hours
Defined contribution plan, minimum age requirement	21
Defined contribution plan, minimum employee contribution of annual compensation	2.00%
Defined contribution plan, maximum employee contribution of annual compensation	80.00%
Defined contribution plan, employer match percentage	25.00%
Defined contribution plan, maximum employee contribution matched by employer	6.00%
Defined contribution plan, percentage at which employees vest annually in employer contributions	20.00%
Defined Contribution Plan Minimum Years of Service Before Vesting Of Employer Contributions	2 years
Defined Benefit Plan, Contributions by Employer	$ 626	$ 548	$ 519