Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I)
-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

Name:	us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Organization and Significant Accounting Policies Self-Insurance Liability (Details) - USD ($)			3 Months Ended	4 Months Ended	8 Months Ended	12 Months Ended
	Jan. 01, 2018	Dec. 31, 2017	Jan. 27, 2018	Apr. 30, 2018	Dec. 31, 2017	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017
Self-Insurance Liability
Estimated self-insurance liability of employee medical claim				$ 1,003,000		$ 965,000	$ 1,003,000
Income Taxes
U.S. federal statutory income tax rate (as a percent)	21.00%	35.00%		21.00%	35.00%	21.00%	30.40%	34.00%
Deferred tax expense			$ 3,100,000			$ 3,300,000	$ 3,300,000