Note 8 - Retirement Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 01, 2022	Dec. 26, 2020	Jan. 01, 2022	Dec. 26, 2020
Service cost including administration	$ 2,377	$ 923	$ 7,131	$ 7,442
Interest cost	1,930	2,302	5,791	6,907
Expected return on plan assets	(4,276)	(4,814)	(12,829)	(11,835)
Amortization of prior service cost	23	22	68	68
Amortization of net loss	0	2,257	0	7,317
Net periodic benefit cost	$ 54	$ 690	$ 161	$ 9,899