Debt (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Debt [Abstract]
Revolving line of credit limit	$ 30,000
Line of credit maturity date	Sep. 23, 2014
Period of fixed interest on line of credit at company's options	1 year
Outstanding drawings on line of credit	10,000	10,000
Effective interest rate (in hundredths)	1.11%
Remaining unused amount under line of credit	$ 20,000