Investments (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 30, 2017	Dec. 31, 2016	Apr. 01, 2017
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	$ 4,092,000		$ 4,092,000		$ 2,582,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	386,000		386,000		361,000
Investments (Textual) [Abstract]
Value of investments to be other-than-temporarily impaired			0
Gross gains realized	147,000	$ 386,000	882,000	$ 1,000,000
Gross losses realized	(41,000)	$ (46,000)	(163,000)	$ (303,000)
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0		0		0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	$ 4,000		$ 4,000		$ 1,000