Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Disaggregation of Revenue [Line Items]
Net sales	$ 431,954	$ 395,755	$ 1,270,624	$ 1,251,136
Home center retailers
Disaggregation of Revenue [Line Items]
Net sales	216,819	191,544	613,932	579,443
Builders
Disaggregation of Revenue [Line Items]
Net sales	161,113	155,169	496,503	512,513
Independent dealers and distributors
Disaggregation of Revenue [Line Items]
Net sales	$ 54,022	$ 49,042	$ 160,189	$ 159,180

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