Marketable Securities (Narrative) (Details) - USD ($)	6 Months Ended
	Sep. 28, 2019	Mar. 30, 2019
Debt Securities, Available-for-sale [Line Items]
Gross unrealized loss	$ (59,000)	$ (641,000)
Amortized cost on available for sale securities held at gross unrealized loss	28,200,000	123,100,000
Securities in a continuous unrealized loss position for more than 12 months, amortized cost	5,500,000	120,300,000
Securities in a continuous unrealized loss position for more than 12 months, aggregate unrealized loss	$ 0	$ 600,000
Minimum
Debt Securities, Available-for-sale [Line Items]
Maturity period for highly-rated securities	1 year
Maximum
Debt Securities, Available-for-sale [Line Items]
Maturity period for highly-rated securities	3 years