Retirement Plans - Net periodic cost (Details) - Pension Plan - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 31, 2019	Sep. 01, 2018	Aug. 31, 2019	Sep. 01, 2018
Net periodic pension expense
Service cost	$ 143	$ 312	$ 285	$ 624
Interest cost	1,556	1,578	3,111	3,156
Expected return on plan assets	(1,214)	(1,435)	(2,427)	(2,869)
Amortization of unrecognized net loss	415	507	830	1,015
Net periodic pension expense	$ 900	$ 962	$ 1,799	$ 1,926