Credit Facility - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended
	Jan. 31, 2013	Mar. 31, 2015
Line Of Credit Facility [Line Items]
Revolving loans and letters of credit	$ 50.0
Additional Credit Facility	50.0
Amount available under credit facility		49.8
Period of credit agreement	3 years
LIBOR rate description		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		0.30%
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%
Excess judgments against the company		$ 10