Note 9 - Retirement Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Service Cost Including Administration	$ 3,259	$ 2,288	$ 6,519	$ 4,572
Interest Cost	2,302	2,296	4,605	4,593
Expected Return on Plan Assets	(3,510)	(3,958)	(7,021)	(7,913)
Amortization of Prior Service Cost	23	30	46	60
Amortization of Net Loss	2,531	0	5,060	0
Net Periodic Benefit Cost	$ 4,605	$ 656	$ 9,209	$ 1,312