Credit Agreement - Additional Information (Detail) - USD ($)	1 Months Ended	9 Months Ended
	Jan. 31, 2013	Sep. 30, 2016	Oct. 31, 2015
Line Of Credit Facility [Line Items]
Revolving loans and letters of credit	$ 50,000,000		$ 100,000,000
Letter of credit outstanding		$ 900,000
Additional Credit Agreement	$ 50,000,000
Amount available under credit agreement		$ 99,100,000
Period of credit agreement	3 years
LIBOR rate description		(A) the sum of (i) the greatest of (a) the prime rate, as defined, (b) the federal funds effective rate plus 0.50% and (c) one month adjusted LIBOR plus 1.00% plus (ii) 0.50% or (B) the sum of (i) adjusted LIBOR plus (ii) 1.50%
Federal funds effective rate		0.50%
One month adjusted LIBOR		1.00%
LIBOR Rate		0.50%
Adjusted LIBOR rate		1.50%
Interest per annum		2.00%
Revolving loan commitment rate		0.40%
Equity interest		65.00%
Maximum [Member]
Line Of Credit Facility [Line Items]
Total leverage ratio		250.00%
Minimum [Member]
Line Of Credit Facility [Line Items]
Interest coverage ratio		350.00%
Adjusted EBITDA		$ 80,000,000
Excess judgments against the company		$ 10,000,000
Standby Letters of Credit [Member]
Line Of Credit Facility [Line Items]
Revolving loans and letters of credit			$ 5,000,000
Credit Agreement [Member]
Line Of Credit Facility [Line Items]
Expiration period of credit agreement		Oct. 31, 2017