Employee Benefit Plans - Components of Net Periodic Pension (Benefit) Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2021	May 31, 2020
Retirement Benefits [Abstract]
Interest cost	$ 2,050	$ 2,881
Expected return on assets	(2,924)	(2,961)
Amortization of net loss	222	0
Net periodic pension benefit	$ (652)	$ (80)