Line of Credit - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Debt Instrument [Line Items]
Total availability under line of credit agreement	$ 10,000,000.0
Line of credit borrowings	0	$ 0
Letters of credit outstanding amount	3,900,000
Available borrowing under letter of credit	$ 6,100,000
Varying interest on line of credit agreement	LIBOR plus 1.5% or Prime less 0.75%
Maturity date of line of credit	Jul. 31, 2017
Maximum ratio of total liabilities to tangible net worth	1
Minimum required fixed coverage charge ratio	1.25
Trailing period used for calculating ratios	12 months
Company's leverage ratio	0.88
Fixed coverage charge ratio	2.23
Line of Credit | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Line of credit interest rate	1.50%
Line of Credit | Prime Rate
Debt Instrument [Line Items]
Line of credit interest rate	0.75%