NOTE H - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Jan. 31, 2016	Apr. 30, 2015
NOTE H - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Line Items]
Fair Value, Less than 12 months	$ 2,145	$ 3,419
Unrealized Losses, Less than 12 months	(417)	(134)
Fair Value, 12 Months or more	2,158	461
Unrealized Losses, 12 Months or more	(498)	(15)
Fair Value	4,303	3,880
Unrealized Losses	(915)	(149)
Fixed Income Securities [Member]
NOTE H - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Line Items]
Fair Value, Less than 12 months	291	96
Unrealized Losses, Less than 12 months	(1)	(1)
Fair Value, 12 Months or more	547	461
Unrealized Losses, 12 Months or more	(24)	(15)
Fair Value	838	557
Unrealized Losses	(25)	(16)
Equity Securities [Member]
NOTE H - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Line Items]
Fair Value, Less than 12 months	1,854	3,323
Unrealized Losses, Less than 12 months	(416)	(133)
Fair Value, 12 Months or more	1,611	0
Unrealized Losses, 12 Months or more	(474)	0
Fair Value	3,465	3,323
Unrealized Losses	$ (890)	$ (133)