Self-Insurance Reserves - Summary of Other Liabilities (Detail) - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2021	Apr. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Beginning balance	$ 9,011	$ 8,423
Additional provision charged to expense	2,484	19,608
Payments	(2,026)	(19,020)
Ending balance	$ 9,469	$ 9,011

Carrying amount (including both current and noncurrent portions) of accrued known and estimated losses incurred as of the balance sheet date for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.24)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Name:	us-gaap_SelfInsuranceReserve
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant