Goodwill and Other Intangible Assets - Schedule of Carrying Value and Accumulated Amortization of Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 10,272	$ 7,933
Accumulated Amortization	4,065	3,247
Customer list
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,757	7,393
Accumulated Amortization	3,664	2,880
Non-Compete Agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,245	270
Accumulated Amortization	202	175
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	270	270
Accumulated Amortization	$ 199	$ 192