Note 8 - Retirement Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Service Cost	$ 2,288	$ 2,442	$ 4,572	$ 4,885
Interest Cost	2,296	2,243	4,593	4,486
Expected Return on Plan Assets	(3,958)	(3,596)	(7,913)	(7,192)
Amortization of Prior Service Cost	30	30	60	60
Amortization of Net Loss		303		605
Net Periodic Benefit Cost	$ 656	$ 1,422	$ 1,312	$ 2,844