Employee Benefit Plan (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Employee Benefit Plan [Abstract]
Matching contribution by employer (in hundredths)	3.00%	3.00%	3.00%
Matching contribution by employer	$ 1,225	$ 1,905	$ 993

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration