Goodwill and Other Intangible Assets - Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Goodwill and Other Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	$ 106,122	$ 109,742
Less accumulated amortization	43,824	42,997
Intangible assets subject to amortization, net	62,298	66,745
Customer relationships
Goodwill and Other Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	92,660	92,660
Non-compete agreements
Goodwill and Other Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	9,427	13,057
Trade names
Goodwill and Other Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	1,939	1,939
Other intangible assets
Goodwill and Other Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	$ 2,096	$ 2,086