Loans Payable and Long-Term Debt (Narrative) (Details)				12 Months Ended			28 Months Ended	60 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 29, 2017 USD ($)	Jan. 25, 2016 USD ($)	Apr. 30, 2019 USD ($)	Apr. 30, 2018 USD ($) loan	Dec. 31, 2005 loan	Apr. 30, 2015 USD ($) lease	Apr. 30, 2019 USD ($)	Feb. 12, 2018 USD ($)
Debt Instrument [Line Items]
Debt, outstanding balance				$ 703,305,000				$ 703,305,000
New Markets Tax Credit Investment			$ 2,300,000
New Markets Tax Credit, Recapture Period			7 years
Debt issuance costs				11,814,000				11,814,000
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
Initial Term Loan [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Amount outstanding				170,000,000	230,000,000			170,000,000
Loan agreement amount		$ 250,000,000
Initial Term Loan and Delayed Draw Loan [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Amount outstanding				340,000,000	460,000,000			340,000,000
Delayed Draw Term Loan [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Amount outstanding				$ 170,000,000	230,000,000			170,000,000
Loan agreement amount		250,000,000
Allegany County, Maryland Site [Member]
Debt Instrument [Line Items]
Number of loan agreements | loan						2
Principal amount forgiven	$ 2,200,000
Accrued interest forgiven	900,000
First American Financial Bancorp [Member]
Debt Instrument [Line Items]
Capital lease obligations incurred								1,500,000
Capital lease term				48 months
Capital lease agreement				$ 500,000	900,000			500,000
e-Plus Group [Member]
Debt Instrument [Line Items]
Number of capitalized lease agreements | lease							19
Capital lease obligations incurred							$ 4,300,000
Number Of Leases 2 | lease							1
Capital Lease Term 2							60 months
Capital lease agreement				$ 2,700,000	2,200,000			$ 2,700,000
e-Plus Group, 36-Month Leases [Member]
Debt Instrument [Line Items]
Number Of Leases | lease							8
Capital lease term							36 months
e-Plus Group, 51-Month Leases [Member]
Debt Instrument [Line Items]
Number Of Leases | lease							10
Capital lease term							51 months
West Virginia Economic Development Authority [Member]
Debt Instrument [Line Items]
Fixed interest rate				2.00%				2.00%
Debt, outstanding balance				$ 3,300,000	$ 3,800,000			$ 3,300,000
Number of loan agreements | loan					2
Capital lease agreement				10,000,000				10,000,000
Principal amount forgiven	2,300,000
Accrued interest forgiven	$ 200,000
4.875% Senior Notes Due 2026 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Loan agreement amount									$ 350,000,000
Debt instrument, interest rate, stated percentage									4.875%
RSI Notes [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value				347,000,000				347,000,000
Long-term Debt				$ 350,000,000				$ 350,000,000
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] | 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]
Amount outstanding				$ 0	$ 0			$ 0
Total Secured Debt To EBITDA Ratio				2.50
Proceeds from term loan		50,000,000
Line of Credit Facility, Commitment Fee Percentage				0.20%
Total Funded Debt To EBITDA Ratio, through January 31, 2020				3.50
Total Funded Debt to EBITDA Ratio, thereafter				3.25
Total Funded Debt to EBITDA Ratio upon Qualified Acquisition				3.75
Fixed Charge Coverage Ratio				1.25
Total Funded Debt to EBITDA Ratio to Permit Unlimited Restricted Payments				2.50
Debt Covenant, Permitted Restricted Payments				$ 50,000,000
Total Funded Debt to EBITDA Ratio, applicable to the exception permitting unlimited restricted payments, amended				2.75
Revolving Credit Facility [Member] | Wells Fargo [Member]
Debt Instrument [Line Items]
Line Of Credit Facility, Agreement Terminated		35,000,000
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Spread on interest rate				0.75%
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Spread on interest rate				1.75%
RSI Home Products, Inc. [Member]
Debt Instrument [Line Items]
Indebtedness assumed (including accrued interest)		$ 589,000,000
RSI Home Products, Inc. [Member] | Initial Term Loan [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Loan term		5 years
RSI Home Products, Inc. [Member] | RSI Notes [Member]
Debt Instrument [Line Items]
Indebtedness assumed (including accrued interest)		$ 589,000,000
RSI Home Products, Inc. [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Proceeds from term loan		$ 50,000,000