Long-Term Debt (Details) (USD $)			0 Months Ended	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Apr. 29, 2013 Secured credit facility	Mar. 31, 2013 Secured credit facility	Dec. 31, 2014 Secured credit facility	Dec. 31, 2013 Secured credit facility	Apr. 29, 2013 Secured credit facility Minimum	Mar. 31, 2013 Secured credit facility Minimum	Apr. 29, 2013 Secured credit facility Maximum	Mar. 31, 2013 Secured credit facility Maximum
Long-Term Debt
Maximum borrowing capacity under the credit facility			$ 50,000,000	$ 55,000,000	$ 35,000,000	$ 42,500,000
Amount outstanding under the credit facility	21,200,000	19,700,000		21,200,000
Interest rate at the end of the period (as a percent)				2.20%
Reference rate			LIBOR	LIBOR
Interest rate added to the reference rate (as a percent)				2.00%			1.25%	2.00%	1.75%	3.25%
Maximum amount allowed to pay dividends and repurchase shares of common stock under modified debt agreement				2,500,000
Remaining maximum borrowings available pursuant to the credit facility				$ 13,871,000
Interest rate added to the reference rate, if the entity entered into the negative pledge (as a percent)							1.50%		2.00%