Note 10 - Retirement Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2022	Jan. 01, 2022	Dec. 31, 2022	Jan. 01, 2022
Service cost including administration	$ 1,310	$ 2,377	$ 6,180	$ 7,131
Interest cost	2,193	1,930	6,941	5,791
Expected return on plan assets	(4,027)	(4,276)	(12,079)	(12,829)
Amortization of prior service cost	22	23	68	68
Amortization of net loss	(205)	0	0	0
Net periodic benefit cost	$ (707)	$ 54	$ 1,110	$ 161