Note 9 - Dividends Payable (Details Textual)	3 Months Ended
	Jun. 30, 2020 USD ($)
Series 1 Preferred Stock [Member]
Dividends, Preferred Stock, Total	$ 13,000
Preferred Stock, Dividend Rate, Percentage	5.00%
Series 2 Preferred Stock [Member]
Dividends, Preferred Stock, Total	$ 13,000
Preferred Stock, Dividend Rate, Percentage	5.00%
Series 3 Preferred Stock [Member]
Dividends, Preferred Stock, Total	$ 7,000
Preferred Stock, Dividend Rate, Percentage	5.00%
Series 2 Preferred Stock and Series 3 Preferred Stock [Member]
Dividends, Preferred Stock, Total	$ 19,000