Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017
Disaggregation of Revenue [Line Items]
Net Sales	$ 1,645,319	$ 1,250,274	$ 1,030,248
Home center retailers
Disaggregation of Revenue [Line Items]
Net Sales	788,803	493,904	352,583
Builders
Disaggregation of Revenue [Line Items]
Net Sales	631,474	557,382	495,441
Independent dealers and distributors
Disaggregation of Revenue [Line Items]
Net Sales	$ 225,042	$ 198,988	$ 182,224

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