Leases (Narrative) (Details) $ in Millions	3 Months Ended
Aug. 31, 2020 USD ($) Facility
Lessee Lease Description [Line Items]
Number of office sublet \| Facility	1
Impairment loss on operating lease	$ 0.2
Other Property and Equipment [Member]
Lessee Lease Description [Line Items]
Impairment loss on operating lease	$ 0.1

Amount of loss from impairment of right-of-use asset from operating lease.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 25
-Paragraph 6
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121593497&loc=SL77918431-209957

Name:	us-gaap_OperatingLeaseImpairmentLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration