Unaudited Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (2,665)	$ 7,443	$ (101,187)	$ 2,157
Other comprehensive income (loss):
Foreign currency translation adjustments	6,122	3,649	(10,887)	5,780
Comprehensive income (loss)	3,457	11,092	(112,074)	7,937
Less: comprehensive income (loss) attributable to non-controlling interest	(9)	10	(28)	19
Comprehensive income (loss) attributable to Mistras Group, Inc.	$ 3,466	$ 11,082	$ (112,046)	$ 7,918