Goodwill and Intangible Assets - Summary of Intangible Assets by Intangible Asset Type (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 33,297	$ 33,331
Less accumulated amortization	(24,872)	(24,079)
Intangible assets, net	8,425	9,252
Covenants Not-to-Compete [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets	17,226	17,266
Less accumulated amortization	(16,148)	(16,198)
Intangible assets, net	1,078	1,068
Client Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets	16,071	16,065
Less accumulated amortization	(8,724)	(7,881)
Intangible assets, net	$ 7,347	$ 8,184