Stockholders' Equity - Schedule of Common Stock Reserved for Future Issuance (Parenthetical) (Details) - shares	1 Months Ended
	Jan. 31, 2021	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance		8,619,509		5,992,019
Montrose 2017 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	1,185,112	7,757,995	135,517	3,944,750
Stock Appreciation Rights Units Grant
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	3,000,000		3,000,000
Common stock issued upon vesting of performance SARs	2,000,000