Note 4 - Inventories - Inventories by Category and Impact of Using LIFO Method (Details) - USD ($)	Dec. 28, 2019	Mar. 31, 2019	Dec. 29, 2018
Finished products	$ 465,306,000	$ 454,920,000	$ 557,652,000
In process	34,685,000	42,045,000	41,100,000
Raw materials and supplies	146,958,000	166,060,000	137,910,000
Total	646,949,000	663,025,000	736,662,000
Less excess of FIFO cost over LIFO cost	153,884,000	161,341,000	160,727,000
Inventories	$ 493,065,000	$ 501,684,000	$ 575,935,000