Line of Credit - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Debt Disclosure [Abstract]
Total availability under line of credit agreement	$ 10.0	$ 10.0
Letters of credit outstanding amount	0.4
Available borrowing under letter of credit	$ 9.6
Varying Interest on Line of credit agreement	LIBOR plus 1.5% or Prime less 0.75%
Line of credit interest rate	1.50%
Maturity date of line of credit	Jul. 31, 2016
Maximum ratio of total liabilities to tangible net worth	1
Minimum required fixed coverage charge ratio	1.25
Period used for calculating ratios	12 months
Company's tangible net worth ratio	0.45
Fixed coverage charge ratio	2.82