Lines of Credit (Details) (Lines of Credit [Member], USD $)	6 Months Ended
	Jun. 30, 2012
Lines of Credit [Member]
Short-term Debt [Line Items]
Credit agreement period	P1Y
Maximum credit limit	$ 10,000,000
Debt instrument, description of variable rate basis	one-month LIBOR rate plus 1.60%
Debt instrument, basis spread on variable rate (in hundredths)	1.60%
Quarterly loan repayment (in hundredths)	0.125%
Line of credit facility, number of covenants	1
Numerator cash flow leverage ratio, maximum	2.5
Denominator cash flow leverage ratio, maximum	1
Multiple of annual lease expense for covenant calculation	6
Rolling period for computation of covenant (in months)	12M
Line of credit facility, amount outstanding	0
Maximum borrowing capacity	$ 10,000,000