Equity - Accumulated Other Comprehensive Income Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2021	Nov. 30, 2020	Nov. 30, 2021	Nov. 30, 2020
AOCI, Net of Tax
Beginning balance	$ 1,254,220	$ 731,504	$ 1,399,879	$ 648,822
Changes in unrealized gains	3,612	0	4,028	0
(Gains) losses reclassified to earnings	(71)	81	(97)	164
Ending balance	1,390,985	891,719	1,390,985	891,719
Total
AOCI, Net of Tax
Beginning balance	365	(1,827)	(25)	(1,910)
Ending balance	3,906	(1,746)	3,906	(1,746)
Unrealized Gains on Derivative Hedges
AOCI, Net of Tax
Beginning balance	2,037	2,025	1,718	2,130
Changes in unrealized gains	3,612	0	4,028	0
(Gains) losses reclassified to earnings	(143)	(107)	(240)	(212)
Ending balance	5,506	1,918	5,506	1,918
Unrealized Losses on Defined Benefit Plans
AOCI, Net of Tax
Beginning balance	(1,672)	(3,852)	(1,743)	(4,040)
Changes in unrealized gains	0	0	0	0
(Gains) losses reclassified to earnings	72	188	143	376
Ending balance	$ (1,600)	$ (3,664)	$ (1,600)	$ (3,664)