Loss Per Share - Calculation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net loss attributable to Charah Solutions, Inc.	$ (4,216)	$ (3,313)	$ (22,002)	$ (24,158)
Deemed and imputed dividends on Series A Preferred Stock	(147)	0	(314)	0
Series A Preferred Stock dividends	(877)	0	(1,846)	0
Net loss attributable to common stockholders	$ (5,240)	$ (3,313)	$ (24,162)	$ (24,158)
Denominator:
Weighted-average shares outstanding (in shares)	29,986	29,605	29,853	29,452
Dilutive share-based awards (in shares)	0	0	0	0
Total weighted average shares outstanding, including dilutive shares (in shares)	29,986	29,605	29,853	29,452
Basic loss per share (in dollars per share)	$ (0.17)	$ (0.11)	$ (0.81)	$ (0.82)
Diluted loss per share (in dollars per share)	$ (0.17)	$ (0.11)	$ (0.81)	$ (0.82)