Retirement Plans - Net periodic cost (Details) - Pension Plan - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2019	Dec. 01, 2018	Nov. 30, 2019	Dec. 01, 2018
Net periodic pension expense
Service cost (credit)	$ 143	$ (12)	$ 428	$ 612
Interest cost	1,556	1,522	4,667	4,678
Expected return on plan assets	(1,214)	(1,415)	(3,641)	(4,285)
Amortization of unrecognized net loss	415	393	1,245	1,407
Net periodic pension expense	$ 900	$ 488	$ 2,699	$ 2,412