Lease Obligations and Other Commitments - Schedule of Gross Amount Assets and Liabilities Related to Operating and Financing Leases (Details) - USD ($) $ in Thousands	Nov. 28, 2020	May 30, 2020
Lease Type
Operating lease ROU asset	$ 2,503	$ 3,018
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	rell:OperatingAndFinanceLeaseRightOfUseAsset	rell:OperatingAndFinanceLeaseRightOfUseAsset
Financing lease ROU asset	$ 354	$ 401
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	rell:OperatingAndFinanceLeaseRightOfUseAsset	rell:OperatingAndFinanceLeaseRightOfUseAsset
Total Lease ROU asset	$ 2,857	$ 3,419
Operating lease liability current	$ 1,121	$ 1,329
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	rell:OperatingAndFinanceLeaseLiabilityCurrent	rell:OperatingAndFinanceLeaseLiabilityCurrent
Financing lease liability current	$ 159	$ 156
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	rell:OperatingAndFinanceLeaseLiabilityCurrent	rell:OperatingAndFinanceLeaseLiabilityCurrent
Total lease liability current	$ 1,280	$ 1,485
Operating lease liability non-current	$ 1,437	$ 1,778
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	rell:OperatingAndFinanceLeaseLiabilityNoncurrent	rell:OperatingAndFinanceLeaseLiabilityNoncurrent
Financing lease liability non-current	$ 75	$ 163
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	rell:OperatingAndFinanceLeaseLiabilityNoncurrent	rell:OperatingAndFinanceLeaseLiabilityNoncurrent
Total lease liability non-current	$ 1,512	$ 1,941