Stockholder's Equity - Schedule of Restricted Stock Activity (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	6 Months Ended
		Jun. 30, 2023	Jun. 30, 2023	Jun. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Awards granted, Shares	[1]		90,116	25,289
Montrose 2017 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Awards granted, Shares		53,164	253,587	0
Awards granted, Average Price per Share			$ 14	$ 16
Montrose 2017 Stock Incentive Plan | Restricted stock units awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Awards granted, Shares		177,096	641,282	106,324
Awards forfeited, Shares		(3,559)	(3,559)
Awards vested, Shares			90,116	25,289
Awards granted, Average Price per Share		$ 37.27	$ 33.9	$ 46.82
Awards forfeited, Average Price per Share		$ 32.16	32.16
Awards vested, Average Price per Share			$ 36.81	$ 30.98
Awards granted, Fair Value		$ 6,600	$ 21,740	$ 4,978
Awards forfeited, Fair Value		$ 114	114
Awards vested, Fair Value			$ 3,317	$ 783

[1] Represents the non-cash release of common shares due to the vesting of restricted stock.