Marketable Securities (Narrative) (Details) $ in Thousands	12 Months Ended
	Mar. 30, 2019 USD ($)	Mar. 31, 2018 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Gross unrealized losses	$ 641	$ 2,433
Amortized cost on available for sale securities held at gross unrealized loss	123,100	$ 198,200
Securities in a continuous unrealized loss position for more than 12 months, amortized cost	120,300
Securities in a continuous unrealized loss position for more than 12 months, aggregate unrealized loss	$ 600
Securities in a continuous unrealized loss position for more than 12 months, number of securities | security		0
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