Employee Retirement Plans (Details 6) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined contribution plan
Company's matching contributions	$ 198	$ 140	$ 123
Non-discretionary employer contributions	871
Non-qualified plan
Employee retirement plans
Expense	471
Amount accrued	$ 497