4. STOCKHOLDERS EQUITY (Details - Preferred Stock Dividends) - Series E Preferred Stock [Member] - USD ($)	12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Fiscal Year 2016, Qtr 1 [Member]
Declaration Date			Jun. 05, 2015
Record date			Jun. 19, 2015
Payment date			Jul. 01, 2015
Total dividends paid			$ 1,034,000
Dividend per share			$ 0.65625
Fiscal Year 2016, Qtr 2 [Member]
Declaration Date			Sep. 08, 2015
Record date			Sep. 18, 2015
Payment date			Oct. 01, 2015
Total dividends paid			$ 1,035,000
Dividend per share			$ 0.65625
Fiscal Year 2016, Qtr 3 [Member]
Declaration Date			Dec. 07, 2015
Record date			Dec. 18, 2015
Payment date			Jan. 04, 2016
Total dividends paid			$ 1,035,000
Dividend per share			$ 0.65625
Fiscal Year 2016, Qtr 4 [Member]
Declaration Date			Mar. 07, 2016
Record date			Mar. 18, 2016
Payment date			Apr. 01, 2016
Total dividends paid			$ 1,035,000
Dividend per share			$ 0.65625
Fiscal Year 2016 [Member]
Total dividends paid			$ 4,139,000
Dividend per share			$ 2.62500
Fiscal Year 2017, Qtr 1 [Member]
Declaration Date		Jun. 02, 2016
Record date		Jun. 17, 2016
Payment date		Jul. 01, 2016
Total dividends paid		$ 1,036,000
Dividend per share		$ 0.65625
Fiscal Year 2017, Qtr 2 [Member]
Declaration Date		Sep. 06, 2016
Record date		Sep. 16, 2016
Payment date		Oct. 03, 2016
Total dividends paid		$ 1,081,000
Dividend per share		$ 0.65625
Fiscal Year 2017, Qtr 3 [Member]
Declaration Date		Dec. 06, 2016
Record date		Dec. 16, 2016
Payment date		Jan. 03, 2017
Total dividends paid		$ 1,081,000
Dividend per share		$ 0.65625
Fiscal Year 2017, Qtr 4 [Member]
Declaration Date		Mar. 09, 2017
Record date		Mar. 20, 2017
Payment date		Apr. 03, 2017
Total dividends paid		$ 1,081,000
Dividend per share		$ 0.65625
Fiscal Year 2017 [Member]
Total dividends paid		$ 4,279,000
Dividend per share		$ 2.62500
Fiscal Year 2018, Qtr 1 [Member]
Declaration Date	Jun. 06, 2017
Record date	Jun. 19, 2017
Payment date	Jul. 03, 2017
Total dividends paid	$ 1,081,000
Dividend per share	$ 0.65625
Fiscal Year 2018, Qtr 2 [Member]
Declaration Date	Sep. 05, 2017
Record date	Sep. 18, 2017
Payment date	Oct. 02, 2017
Total dividends paid	$ 1,081,000
Dividend per share	$ 0.65625
Fiscal Year 2018, Qtr 3 [Member]
Declaration Date	Dec. 07, 2017
Record date	Dec. 18, 2017
Payment date	Jan. 02, 2018
Total dividends paid	$ 1,081,000
Dividend per share	$ 0.65625
Fiscal Year 2018, Qtr 4 [Member]
Declaration Date	Mar. 07, 2018
Record date	Mar. 19, 2018
Payment date	Apr. 02, 2018
Total dividends paid	$ 1,082,000
Dividend per share	$ 0.65625
Fiscal Year 2018 [Member]
Total dividends paid	$ 4,325,000
Dividend per share	$ 2.625