Business and Summary of Significant Accounting Policies (Details) $ in Millions	6 Months Ended
Sep. 26, 2020 USD ($)
Accounting Policies [Abstract]
Amount of lease payments deferred due to COVID-19	$ 3.7
Amount of lease payments deferred with a signed agreement due to COVID-19	$ 3.6

Lease Payment Deferral With Signed Agreement, COVID-19

No definition available.

Name:	snbr_LeasePaymentDeferralWithSignedAgreementCOVID19
Namespace Prefix:	snbr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration