Goodwill and Other Intangible Assets - Summary of Gross Amounts and Accumulated Amortization of Identifiable Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 24,925	$ 24,925
Accumulated Amortization	11,632	9,964
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	19,000	19,000
Accumulated Amortization	7,439	6,086
Covenants not-to-Compete [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	4,425	4,425
Accumulated Amortization	4,001	3,786
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	1,500	1,500
Accumulated Amortization	$ 192	$ 92