Balances Related to Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 100,846	$ 101,878
Accumulated Amortization	(50,217)	(50,693)
Net Carrying Amount	50,629	51,185
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	95,287	94,808
Accumulated Amortization	(45,833)	(44,846)
Net Carrying Amount	$ 49,454	49,962
Customer relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life in Years	15 years
Customer relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life in Years	20 years
Trade names/trademarks
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 5,200	5,200
Accumulated Amortization	(4,246)	(4,164)
Net Carrying Amount	$ 954	1,036
Trade names/trademarks | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life in Years	5 years
Trade names/trademarks | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life in Years	7 years
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life in Years	5 years
Gross Carrying Amount	$ 300	1,810
Accumulated Amortization	(103)	(1,648)
Net Carrying Amount	$ 197	162
Other
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life in Years	20 years
Gross Carrying Amount	$ 59	60
Accumulated Amortization	(35)	(35)
Net Carrying Amount	$ 24	$ 25