Employee Benefit Plans - Obligations and Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2022	May 31, 2021
Change in benefit obligation:
Projected benefit obligation, beginning of year	$ 99,728	$ 105,357
Interest cost	2,148	2,050
Actuarial gain	(14,044)	(4,460)
Benefits paid	(3,286)	(3,219)
Projected benefit obligation, end of year	84,546	99,728
Change in plan assets:
Fair value of plan assets, beginning of year	78,244	68,341
Actual (loss) return on plan assets	(8,322)	9,509
Employer contributions	87	3,613
Benefits paid	(3,286)	(3,219)
Fair value of plan assets, end of year	66,723	78,244
Funded status-net amount recognized	$ (17,823)	$ (21,484)