Stockholders' Equity - Schedule of Common Stock Reserved for Future Issuance (Parenthetical) (Details) - shares	1 Months Ended
	Jan. 31, 2021	Mar. 31, 2024		Jan. 31, 2024	Mar. 31, 2023		Jan. 31, 2023	Jan. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance		10,475,763			9,555,449
Montrose 2017 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance		9,692,222	[1]	1,207,563	8,722,930	[1]	1,189,801
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
Common stock issued upon vesting of performance SARs	2,000,000

[1] In January 2024 and 2023, the Board of Directors ratified the addition of 1,207,563 and 1,189,801 shares of common stock, respectively, to the number of shares available for issuance under the 2017 Plan pursuant to the annual increase provision of such plan. Unless the Board of Directors determines otherwise, additional annual increases will be effective on each January 1, through January 1, 2027. The 2017 Plan permits the company to settle awards, if and when vested, in cash at its discretion. Pursuant to the terms of the 2017 Plan, the number of shares authorized for issuance thereunder will only be reduced with respect to shares of common stock actually issued upon exercise or settlement of an award. Shares of common stock subject to awards that have been canceled, expired, forfeited, or otherwise not issued under an award and shares of common stock subject to awards settled in cash do not count as shares of common stock issued under the 2017 Plan. The Company expects to have sufficient shares available under the 2017 Plan to satisfy the future settlement of outstanding awards. Shares reserved for future issuance include 3,000,000 shares underlying the 3,000,000 performance SARs granted in December 2021 that are subject to vesting based on the achievement of certain market conditions. Assuming achievement at the highest price performance hurdle, approximately 2,000,000 shares of common stock would be issued upon vesting of these performance SARs. To date, none of the market conditions have been achieved.