Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Total Mistras Group, Inc. Stockholders’ Equity	Common Stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Noncontrolling Interest
Balance at May. 31, 2013	$ 210,280	$ 210,053	$ 282	$ 195,241	$ 18,982	$ (4,452)	$ 227
Balance (in shares) at May. 31, 2013			28,211
Increase (Decrease) in Stockholders' Equity
Net income	22,575	22,518			22,518		57
Other comprehensive (income) loss, net of tax	2,945	2,941				2,941	4
Share-based payments	6,261	6,261		6,261
Share-based payments (in shares)			19
Net settlement on vesting of restricted stock units	(1,006)	(1,006)	$ 1	(1,007)
Net settlement on vesting of restricted stock units (in shares)			123
Excess tax benefit from share-based payment compensation	340	340		340
Exercise of stock options	997	997	$ 1	996
Exercise of stock options (in shares)			103
Balance at May. 31, 2014	242,392	242,104	$ 284	201,831	41,500	(1,511)	288
Balance (in shares) at May. 31, 2014			28,456
Increase (Decrease) in Stockholders' Equity
Net income	15,991	16,081			16,081		(90)
Other comprehensive (income) loss, net of tax	(19,607)	(19,602)				(19,602)	(5)
Share-based payments	6,579	6,579		6,579
Share-based payments (in shares)			21
Net settlement on vesting of restricted stock units	(1,481)	(1,481)	$ 2	(1,483)
Net settlement on vesting of restricted stock units (in shares)			161
Excess tax benefit from share-based payment compensation	388	388		388
Exercise of stock options	750	750	$ 1	749
Exercise of stock options (in shares)			65
Balance at May. 31, 2015	245,012	244,819	$ 287	208,064	57,581	(21,113)	193
Balance (in shares) at May. 31, 2015			28,703
Increase (Decrease) in Stockholders' Equity
Net income	24,650	24,654			24,654		(4)
Other comprehensive (income) loss, net of tax	950	1,014				1,014	(64)
Share-based payments	6,394	6,394		6,394
Net settlement on vesting of restricted stock units	(1,091)	(1,091)	$ 2	(1,093)
Net settlement on vesting of restricted stock units (in shares)			182
Excess tax benefit from share-based payment compensation	(170)	(170)		(170)
Exercise of stock options	543	543	$ 1	542
Exercise of stock options (in shares)			55
Balance at May. 31, 2016	$ 276,288	$ 276,163	$ 290	$ 213,737	$ 82,235	$ (20,099)	$ 125
Balance (in shares) at May. 31, 2016			28,940