Property and Equipment - Schedule of Property and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Gross	$ 97,857	$ 81,615
Less: accumulated deprecation and amortization	(58,487)	(52,140)
Property Plant And Equipment Net	39,370	29,475
Land [Member]
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Gross	66	66
Building [Member]
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Gross	218	218
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Gross	4,028	3,640
Furniture, Fixtures and Equipment[Member]
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Gross	17,814	15,720
Vehicles and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Gross	$ 75,731	$ 61,971