Marketable Securities (Narrative) (Details) $ in Thousands	6 Months Ended
	Sep. 23, 2017 USD ($) security	Mar. 25, 2017 USD ($) security
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses	$ 103	$ 55
Amortized cost on available for sale securities held at gross unrealized loss	$ 78,200	$ 99,900
Number of securities in unrealized loss position greater than one year | security	0	4
Percentage of gross unrealized loss to position (less than)		1.00%
Minimum
Schedule of Available-for-sale Securities [Line Items]
Maturity period for highly-rated securities	1 year
Maximum
Schedule of Available-for-sale Securities [Line Items]
Maturity period for highly-rated securities	3 years