Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 428,016	$ 424,878	$ 855,381	$ 853,840
Home center retailers
Disaggregation of Revenue [Line Items]
Net sales	189,148	196,542	387,899	401,591
Builders
Disaggregation of Revenue [Line Items]
Net sales	184,755	169,596	357,344	334,680
Independent dealers and distributors
Disaggregation of Revenue [Line Items]
Net sales	$ 54,113	$ 58,740	$ 110,138	$ 117,569

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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

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