Note 8 - Retirement Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 02, 2021	Sep. 26, 2020	Oct. 02, 2021	Sep. 26, 2020
Service cost including administration	$ 2,560	$ 3,259	$ 5,121	$ 6,519
Interest cost	1,878	2,302	3,756	4,605
Expected return on plan assets	(4,276)	(3,510)	(8,553)	(7,021)
Amortization of prior service cost	23	23	46	46
Amortization of net loss	0	2,531	0	5,060
Net periodic benefit cost	$ 185	$ 4,605	$ 370	$ 9,209