Awards and Restricted Stock Units Issued under 2007 Plan and 2014 Omnibus Plan (Detail) - 2007 Plan and 2014 Omnibus Plan - $ / shares	12 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2019
Weighted-Average Grant-Date Fair Value
Beginning Balance	$ 33.82
Shares granted	78.49	$ 62.17	$ 60.01
Shares exercised	33.25
Ending Balance	$ 37.89	$ 33.82
Shares
Beginning Balance	446,000
Shares granted	35,102
Shares exercised	(63,000)
Ending Balance	418,000	446,000