Business Acquisitions - Additional Information (Details) - USD ($)	1 Months Ended			3 Months Ended		6 Months Ended
	Apr. 30, 2021	Jan. 31, 2021	Apr. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Business Acquisition [Line Items]
Transaction costs related to business combinations				$ 506,000	$ 2,454,000	$ 743,000	$ 3,761,000
Number of common stock shares issued in connection with business acquisition				9,322	791,139	81,062	791,139
Revenues from discontinued service lines				$ 0	$ 1,300,000	$ 0	$ 3,800,000
MSE Group
Business Acquisition [Line Items]
Percentage of interests acquired		100.00%
Number of common stock shares issued in connection with business acquisition						71,740
MSE Group | Customer Relationships
Business Acquisition [Line Items]
Weighted average useful lives for acquired intangible assets		7 years
MSE Group | Related Backlog
Business Acquisition [Line Items]
Weighted average useful lives for acquired intangible assets		2 years
MSE Group | Trade Names
Business Acquisition [Line Items]
Weighted average useful lives for acquired intangible assets		2 years
MSE Group | Covenants Not to Compete
Business Acquisition [Line Items]
Weighted average useful lives for acquired intangible assets		5 years
Vista
Business Acquisition [Line Items]
Percentage of interests acquired				100.00%		100.00%
Number of common stock shares issued in connection with business acquisition						9,322
MSE Group and Vista
Business Acquisition [Line Items]
Revenue				$ 3,900,000		$ 7,800,000
Pre-tax (loss) income				100,000		(200,000)
MSE Group and Vista | 2022 Earn Out
Business Acquisition [Line Items]
Business combination, earn-out payment, maximum				7,200,000		7,200,000
MSE Group and Vista | 2023 Earn Out
Business Acquisition [Line Items]
Business combination, earn-out payment, maximum				$ 7,200,000		$ 7,200,000
CTEH
Business Acquisition [Line Items]
Percentage of interests acquired			100.00%
Number of common stock shares issued in connection with business acquisition			791,139
CTEH | External Proprietary Software
Business Acquisition [Line Items]
Weighted average useful lives for acquired intangible assets			5 years
CTEH | Customer Relationships
Business Acquisition [Line Items]
Weighted average useful lives for acquired intangible assets			15 years
CTEH | Trade Names
Business Acquisition [Line Items]
Weighted average useful lives for acquired intangible assets			5 years
CTEH | Covenants Not to Compete
Business Acquisition [Line Items]
Weighted average useful lives for acquired intangible assets			5 years
CTEH | Proprietary Software
Business Acquisition [Line Items]
Weighted average useful lives for acquired intangible assets			3 years
CTEH | 2020 Earn Out
Business Acquisition [Line Items]
Business combination, earn-out payment, maximum			$ 50,000,000.0
Business combination, contingent consideration arrangements, basis for amount						The CTEH first year earn-out was calculated at twelve times CTEH’s 2020 EBITDA (as defined in the purchase agreement) in excess of $18.3 million, with a maximum first year earn-out payment of $50.0 million, which was fully achieved.
Business combination, contingent consideration arrangements, description						The 2020 earn-out was initially payable 100.0% in common stock, but as a result of the completion of the Company’s IPO (Note 1), 50.0% was payable in cash. In April 2021, the 2020 earn-out payment was made with 50.0% paid in cash and the remaining 50.0% paid in common stock of the Company (Notes 14 and 18).
Business combination, minimum EBITDA for contingent consideration arrangements			$ 18,300,000
Percentage of earn out payable in common stock			100.00%
Percentage of earn out paid in cash, as result of completing of IPO	50.00%
Percentage of earn out paid in common stock, as a result of completion of IPO	50.00%
CTEH | 2020 Earn Out | Minimum
Business Acquisition [Line Items]
Business combination, actual EBITDA			$ 18,300,000
CTEH | 2020 Earn Out | Maximum
Business Acquisition [Line Items]
Business combination, actual EBITDA			22,500,000
CTEH | 2021 Earn Out
Business Acquisition [Line Items]
Business combination, earn-out payment, maximum			$ 30,000,000.0
Business combination, contingent consideration arrangements, basis for amount						The second year earn-out is to be calculated at ten times CTEH’s 2021 EBITDA in excess of actual 2020 EBITDA (with actual 2020 EBITDA subject to a minimum of $18.3 million and a maximum of $22.5 million), with a maximum second year earn-out payment of $30.0 million.
Business combination, contingent consideration arrangements, description						The 2021 earn-out, if any, is payable 100.0% in cash.
Percentage of earn out payable in cash			100.00%
Other Acquisition | Covenants Not to Compete
Business Acquisition [Line Items]
Weighted average useful lives for acquired intangible assets			4 years