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Loans Payable and Long-Term Debt (Narrative) (Details)							2 Months Ended	12 Months Ended		28 Months Ended	60 Months Ended
Loans Payable and Long-Term Debt (Narrative) (Details)	Apr. 30, 2020	Apr. 30, 2019	Feb. 28, 2018 USD ($)	Feb. 26, 2018 USD ($)	Dec. 29, 2017 USD ($)	Jan. 25, 2016 USD ($)	Jun. 29, 2018 USD ($)	Apr. 30, 2018 USD ($) group	Dec. 31, 2005 loan	Apr. 30, 2015 USD ($) lease	Apr. 30, 2018 USD ($) lease	Feb. 12, 2018 USD ($)	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)
Debt Instrument [Line Items]
Number Of Non-Employee Director Groups \| group								1
Total Secured Debt To EBITDA Ratio								2.50
Debt, outstanding balance								$ 828,344,000			$ 828,344,000
New Markets Tax Credit Investment						$ 2,300,000
New Markets Tax Credit, Recapture Period						7 years
Debt issuance costs								$ 14,304,000			14,304,000
Deferred Finance Costs, Amortization Period								5 years
Notes Payable to Banks [Member]
Debt Instrument [Line Items]
LIBOR rate						1.20%
Loan agreement amount						$ 6,600,000
Loan term						30 years
Debt issuance costs						$ 300,000
Deferred Finance Costs, Amortization Period						30 years
Other Noncurrent Assets [Member]
Debt Instrument [Line Items]
Notes, Loans and Financing Receivable, Net, Noncurrent						$ 4,300,000
Long-term Debt [Member]
Debt Instrument [Line Items]
Amount drawn on loan								$ 6,700,000			6,700,000		$ 5,900,000
Subordinated Promissory Notes Payable To Certain Current And Former RSI Employees [Member] \| Subordinated Debt [Member]
Debt Instrument [Line Items]
Loan agreement amount					$ 2,800,000
Loan term					5 years
Initial Term Loan [Member] \| Loans Payable [Member]
Debt Instrument [Line Items]
Amount outstanding								230,000,000			230,000,000
Loan agreement amount					$ 250,000,000
Delayed Draw Term Loan [Member] \| Loans Payable [Member]
Debt Instrument [Line Items]
Amount outstanding								$ 230,000,000			$ 230,000,000
Loan agreement amount					250,000,000
Allegany County, Maryland Site [Member]
Debt Instrument [Line Items]
Fixed interest rate								3.00%			3.00%
Debt, outstanding balance								$ 2,200,000			$ 2,200,000
Number of loan agreements \| loan									2
First American Financial Bancorp [Member]
Debt Instrument [Line Items]
Number of capitalized lease agreements \| lease											12
Capital lease obligations incurred											$ 2,000,000
Capital lease term								48 months
Capital lease agreement								$ 900,000			900,000		1,400,000
e-Plus Group [Member]
Debt Instrument [Line Items]
Number of capitalized lease agreements \| lease										19
Capital lease obligations incurred										$ 3,200,000
Number Of Leases \| lease										15
Capital lease term										51 months
Number Of Leases 2 \| lease										4
Capital Lease Term 2										36 months
Capital lease agreement								$ 2,200,000			$ 2,200,000		1,000,000
West Virginia Economic Development Authority [Member]
Debt Instrument [Line Items]
Fixed interest rate								2.00%			2.00%
Debt, outstanding balance								$ 3,800,000			$ 3,800,000		$ 4,400,000
Capital lease agreement								10,000,000			10,000,000
West Virginia Economic Development Authority, Originated in 2015 [Member]
Debt Instrument [Line Items]
Fixed interest rate										3.00%
Debt, outstanding balance										$ 1,500,000
West Virginia Economic Development Authority, Originated in 2016 [Member]
Debt Instrument [Line Items]
Fixed interest rate														3.00%
Debt, outstanding balance														$ 800,000
4.875% Senior Notes Due 2026 [Member] \| Notes Payable to Banks [Member]
Debt Instrument [Line Items]
Amount outstanding								$ 350,000,000			$ 350,000,000
Fixed interest rate												4.875%
Loan agreement amount												$ 350,000,000
RSI Notes [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Repayments of Debt			$ 10,900,000	$ 115,000,000
Debt Instrument, Repurchase Amount												$ 449,100,000
Long-term Debt, Fair Value					$ 602,300,000
Minimum [Member] \| Subordinated Promissory Notes Payable To Certain Current And Former RSI Employees [Member] \| Subordinated Debt [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage					1.01%
Minimum [Member] \| First American Financial Bancorp [Member]
Debt Instrument [Line Items]
Market interest rate								3.50%			3.50%
Minimum [Member] \| e-Plus Group [Member]
Debt Instrument [Line Items]
Market interest rate								3.50%			3.50%
Maximum [Member] \| Subordinated Promissory Notes Payable To Certain Current And Former RSI Employees [Member] \| Subordinated Debt [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage					2.12%
Maximum [Member] \| First American Financial Bancorp [Member]
Debt Instrument [Line Items]
Market interest rate								6.50%			6.50%
Maximum [Member] \| e-Plus Group [Member]
Debt Instrument [Line Items]
Market interest rate								6.50%			6.50%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Repayments of Lines of Credit					$ 30,000,000
Amount outstanding								$ 0			$ 0
Required minimum ratio of cash flow to fixed charges under agreement								125.00%
Applicable Funded Debt To EBITDA Ratio								3.75
Total Secured Debt To EBITDA Ratio								1.87
Proceeds from term loan					50,000,000
Line of Credit Facility, Commitment Fee Percentage								0.30%
Total Funded Debt To EBITDA Ratio								3.25
Revolving Credit Facility [Member] \| Wells Fargo [Member]
Debt Instrument [Line Items]
Line Of Credit Facility, Agreement Terminated					$ 35,000,000
Revolving Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Ratio cash flow to fixed charges								312.00%
London Interbank Offered Rate (LIBOR) [Member] \| Revolving Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Spread on interest rate								1.25%
London Interbank Offered Rate (LIBOR) [Member] \| Revolving Credit Facility [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Spread on interest rate								2.25%
Scenario, Forecast [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Applicable Funded Debt To EBITDA Ratio	3.25	3.50
LEVEL 2 [Member] \| 4.875% Senior Notes Due 2026 [Member] \| Notes Payable to Banks [Member]
Debt Instrument [Line Items]
Debt Instrument, Fair Value Disclosure								$ 339,000,000			$ 339,000,000
Subsequent Event [Member]
Debt Instrument [Line Items]
Repayments of Debt							$ 40,000,000