Goodwill and Intangible Assets - Components of Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 33,331	$ 33,367
Less accumulated amortization	(22,893)	(21,559)
Intangible assets, net	10,438	11,808
Covenants Not-to-Compete [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets	17,266	17,296
Less accumulated amortization	(15,957)	(15,730)
Intangible assets, net	1,309	1,566
Client Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets	16,065	16,071
Less accumulated amortization	(6,936)	(5,829)
Intangible assets, net	$ 9,129	$ 10,242