Goodwill and Intangible Assets - Summary of Carrying Values of Finite-Lived Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 151,566	$ 36,876
Accumulated Amortization	48,651	31,925
Total	102,915	4,951
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	109,551	32,823
Accumulated Amortization	37,784	31,604
Total	71,767	1,219
Technology [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	16,577	3,610
Accumulated Amortization	5,347	295
Total	11,230	3,315
Backlog [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	13,000
Accumulated Amortization	4,875
Total	8,125
Trade Name [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	12,438	443
Accumulated Amortization	645	26
Total	$ 11,793	$ 417