Goodwill and Other Intangible Assets - Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	$ 104,694	$ 109,742
Less accumulated amortization	45,462	42,997
Intangible assets subject to amortization, net	59,232	66,745
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	91,719	92,660
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	8,940	13,057
Trade names
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	1,939	1,939
Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	$ 2,096	$ 2,086