Summary of Significant Accounting Policies - Financial Instruments (Details) - USD ($) $ in Millions	May 31, 2023	May 31, 2022
Accounts Receivable
Accounts receivable, net	$ 241.3	$ 214.0
U.S. Government contracts:
Accounts Receivable
Accounts receivable, net	32.0	57.5
U.S. Government contracts: \| Trade receivables
Accounts Receivable
Trade receivables	13.1	31.6
U.S. Government contracts: \| Unbilled receivables
Accounts Receivable
Unbilled receivables	18.9	25.9
All other customers:
Accounts Receivable
Accounts receivable, net	209.3	156.5
All other customers: \| Trade receivables
Accounts Receivable
Trade receivables	179.7	136.8
All other customers: \| Unbilled receivables
Accounts Receivable
Unbilled receivables	$ 29.6	$ 19.7

The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(5))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-06(3))
-URI https://asc.fasb.org/extlink&oid=120401414&loc=d3e604059-122996

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 10
-URI https://asc.fasb.org/extlink&oid=84165509&loc=d3e56426-112766

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant