Condensed Consolidated & Combined Statements of Stockholders' and Members' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings (Losses)	Total	Non-Controlling Interest	Charah, LLC Members' Interest	Allied Power Management, LLC Members' Interest
Balance beginning of period, Stockholders' Equity at Dec. 31, 2017	$ 48,319	$ 0	$ 0	$ 18,316	$ 47,721	$ 598	$ 19,718	$ 9,687
Balance beginning of period (shares) at Dec. 31, 2017		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	5,034			4,025	4,025	1,009
Share based compensation expense	214				214		214
Distributions	(1,407)				(686)	(721)	(686)
Conversion from members' interest to common stock (shares)		23,436,398
Conversion from members' interest to common stock	0	$ 234	28,699				(19,246)	(9,687)
Issuance of shares (shares)		5,294,117
Issuance of shares	59,241	$ 53	59,188		59,241
Shares issued under share-based compensation plans (in shares)		372,169
Shares issued under share-based compensation plans	0	$ 4	(4)
Shares repurchased (in shares)		(19,696)
Shares repurchased	0	$ 0	0		0
Share-based compensation expense	1,189		1,189		1,189
Deferred offering costs	(8,622)		(8,622)		(8,622)
Balance end of period, Stockholders' Equity at Jun. 30, 2018	103,968	$ 291	80,450	22,341	103,082	886	0	0
Balance end of period (shares) at Jun. 30, 2018		29,082,988
Balance beginning of period, Stockholders' Equity at Mar. 31, 2018	49,218	$ 0	0	19,121	48,636	582	19,828	9,687
Balance beginning of period (shares) at Mar. 31, 2018		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	3,862			3,220	3,220	642
Share based compensation expense	104				104		104
Distributions	(1,024)				(686)	(338)	(686)
Conversion from members' interest to common stock (shares)		23,436,398
Conversion from members' interest to common stock	0	$ 234	28,699				(19,246)	(9,687)
Issuance of shares (shares)		5,294,117
Issuance of shares	59,241	$ 53	59,188		59,241
Shares issued under share-based compensation plans (in shares)		372,169
Shares issued under share-based compensation plans	0	$ 4	(4)
Shares repurchased (in shares)		(19,696)
Shares repurchased	0	$ 0	0		0
Share-based compensation expense	1,189		1,189		1,189
Deferred offering costs	(8,622)		(8,622)		(8,622)
Balance end of period, Stockholders' Equity at Jun. 30, 2018	103,968	$ 291	80,450	22,341	103,082	886	$ 0	$ 0
Balance end of period (shares) at Jun. 30, 2018		29,082,988
Balance beginning of period, Stockholders' Equity at Dec. 31, 2018	$ 93,390	$ 291	82,880	9,414	92,585	805
Balance beginning of period (shares) at Dec. 31, 2018	29,082,988	29,082,988
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	$ (19,619)			(20,845)	(20,845)	1,226
Share based compensation expense	1,007		1,007		1,007
Distributions	(1,008)					(1,008)
Shares issued under share-based compensation plans (in shares)		531,830
Shares issued under share-based compensation plans	0	$ 5	(5)
Shares repurchased (in shares)		(28,653)
Shares repurchased	(201)		(201)		(201)
Balance end of period, Stockholders' Equity at Jun. 30, 2019	$ 73,569	$ 296	83,681	(11,431)	72,546	1,023
Balance end of period (shares) at Jun. 30, 2019	29,586,165	29,586,165
Balance beginning of period, Stockholders' Equity at Mar. 31, 2019	$ 90,673	$ 296	83,083	6,595	89,974	699
Balance beginning of period (shares) at Mar. 31, 2019		29,554,588
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(17,276)			(18,026)	(18,026)	750
Share based compensation expense	799		799		799
Distributions	(426)					(426)
Shares issued under share-based compensation plans (in shares)		31,577
Shares issued under share-based compensation plans	0	$ 0	0
Shares repurchased (in shares)		0
Shares repurchased	(201)		(201)		(201)
Balance end of period, Stockholders' Equity at Jun. 30, 2019	$ 73,569	$ 296	$ 83,681	$ (11,431)	$ 72,546	$ 1,023
Balance end of period (shares) at Jun. 30, 2019	29,586,165	29,586,165