Acquisitions and Joint Ventures - Schedule of Estimated Fair Values of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Jul. 31, 2020	Jun. 04, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill	$ 161,652	$ 161,820			$ 152,020
Mader Holdings L.P. | Joint Venture Agreement
Business Acquisition [Line Items]
Current assets			$ 2,040
Property and equipment			103
Goodwill			2,085
Total assets acquired			4,515
Current liabilities assumed			(515)
Deferred income tax asset			287
Other liabilities			(500)
Long term debt			(2,508)
Fair value of 30% noncontrolling equity interest in Mader			$ 992
Environmental Integrated Solutions [Member]
Business Acquisition [Line Items]
Current assets				$ 6,416
Property and equipment				26
Other assets				44
Goodwill				7,022
Intangible - finite life				4,840
Total assets acquired				18,348
Current liabilities assumed				(6,514)
Deferred income tax liability				(920)
Net assets acquired				$ 10,914