Consolidated Statements of Changes in Equity (USD $) In Thousands, unless otherwise specified	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, 2012	$ 193,248	$ 193,012	$ 280	$ 188,443	$ 7,336	$ (3,047)	$ 236
Balance (in shares) at May. 31, 2012			28,026
Increase (Decrease) in Stockholders' Equity
Net income	16,228	16,195			16,195		33
Other comprehensive income, net of tax	1,119	1,119				1,119
Stock compensation	4,749	4,749		4,749
Stock compensation (in shares)			13
Net settlement on vesting of restricted stock units	(806)	(806)	1	(807)
Net settlement on vesting of restricted stock units (in shares)			85
Excess tax benefit from stock compensation	455	455		455
Exercise of stock options	673	673	1	672
Exercise of stock options (in shares)			71
Balance at Feb. 28, 2013	$ 215,666	$ 215,397	$ 282	$ 193,512	$ 23,531	$ (1,928)	$ 269
Balance (in shares) at Feb. 28, 2013			28,195