Investments (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 26, 2015	Dec. 31, 2016	Dec. 26, 2015	Apr. 02, 2016
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	$ 4,193,000		$ 4,193,000		$ 2,630,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(373,000)		(373,000)		(530,000)
Investments (Textual) [Abstract]
Value of investments to be other-than-temporarily impaired	0
Gross gains realized	386,000	$ 74,000	1,047,000	$ 305,000
Gross losses realized	(46,000)	$ (51,000)	(303,000)	$ (163,000)
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	(1,000)		(1,000)		(3,000)
Common stock of industrial and other companies [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	8,908,000		8,908,000		7,744,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	$ (133,000)		$ (133,000)		(409,000)
Common stock of bank trust, insurance, and public utility companies [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value					100,000
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax					$ (3,000)