Retirement Plans - Benefit obligation and funded status (Details) - Pension Plan - USD ($) $ in Thousands	3 Months Ended
May 30, 2020	Jun. 01, 2019
Change in benefit obligations:
Interest cost	$ 1,199	$ 1,556
Change in plan assets:
Employer contributions	$ 0

Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Name:	us-gaap_DefinedBenefitPlanContributionsByEmployer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration