Note 8 - Subsequent Events (Details Textual) - HC Government Realty Trust, Inc [Member] - USD ($)		Apr. 09, 2020	Apr. 03, 2020	Mar. 19, 2019	Apr. 29, 2020	Mar. 31, 2020	Dec. 31, 2019
Equity Method Investment, Ownership Percentage						16.00%	16.40%
Subsequent Event [Member]
Equity Method Investment, Ownership Percentage					25.90%
Series B Cumulative Convertible Preferred Stock [Member]
Equity Method Investment, Shares Purchased During Period (in shares)				200,000
Equity Method Investment, Aggregate Cost				$ 2,000,000
Equity Method Investment, Ownership Percentage	[1]					7.70%	7.90%
Series B Cumulative Convertible Preferred Stock [Member] | Subsequent Event [Member]
Equity Method Investment, Shares Purchased During Period (in shares)		250,000	100,000
Equity Method Investment, Aggregate Cost		$ 2,500,000	$ 1,000,000

[1] Represents investments in shares of HC Realty preferred stock with a basis of $2 million. Each share of preferred stock can be converted into one share of HC Realty common stock at a conversion price equal to the lesser of $9.10 per share or the fair market value per share of HC Realty common stock, subject to adjustment upon the occurrence of certain events.