Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Disaggregation of Revenue [Line Items]
Net sales	$ 448,583	$ 428,016	$ 838,670	$ 855,381
Home center retailers
Disaggregation of Revenue [Line Items]
Net sales	223,118	189,148	397,113	387,899
Builders
Disaggregation of Revenue [Line Items]
Net sales	171,042	184,755	335,390	357,344
Independent dealers and distributors
Disaggregation of Revenue [Line Items]
Net sales	$ 54,423	$ 54,113	$ 106,167	$ 110,138

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration