Note 3 - Investment in Affiliate - Equity Method Investments (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Investment in affiliate, balance		$ 10,723		$ 10,723		$ 10,850
Gross unrealized losses		$ 77	$ (96)	$ (44)	$ (189)
HC Government Realty Trust, Inc [Member]
Ownership percentage		26.05%	33.90%	26.05%	33.90%
Investment in affiliate, balance		$ 10,723	$ 10,850	$ 10,723	$ 10,850
Gross unrealized losses	[1]	$ 77	$ (96)	$ (44)	$ (189)
HC Government Realty Trust, Inc [Member] | Series B Cumulative Convertible Preferred Stock [Member]
Ownership percentage	[2]	22.49%	26.80%	22.49%	26.80%
Investment in affiliate, balance	[2]	$ 10,250	$ 10,250	$ 10,250	$ 10,250
Gross unrealized losses	[1],[2]	$ 0	$ 0	$ 0	$ 0
HC Government Realty Trust, Inc [Member] | Common Stock of Investee [Member]
Ownership percentage		3.56%	7.10%	3.56%	7.10%
Investment in affiliate, balance		$ 473	$ 600	$ 473	$ 600
Gross unrealized losses	[1]	$ 77	$ (96)	$ (44)	$ (189)

[1] Loss from these investments is included in “Loss from affiliate” in the Unaudited Consolidated Statements of Operations. Since HC Realty is a REIT and not a taxable entity, the loss is not reported net of taxes.

[2] Represents investments in shares of HC Series B Stock with a basis of $10.25 million. Each share of HC Series B Stock can be converted into one share of HC Common Stock at a conversion price equal to the lesser of $9.10 per share or the fair market value per share of HC Common Stock, subject to adjustment upon the occurrence of certain events.