Note 6 - Investment in Affiliate (Details Textual)		3 Months Ended
	Mar. 19, 2019 USD ($) shares	Mar. 31, 2019 ft² $ / shares shares	Aug. 31, 2015
Percentage of GSA-leased Properties Owned By the Largest Owner of GSA-leased Properties			3.50%
Percentage of GSA-leased Properties Owned By the Ten Largest Owners of GSA-leased Properties			17.00%
HC Government Realty Trust, Inc [Member]
Number of Real Estate Properties		16
Number of GSA Properties for Which the Entity Owns All Rights, Benefits and Burdens of Ownership		3
HC Government Realty Trust, Inc [Member] | Minimum [Member]
Rentable Area of Each GSA Property Invested In | ft²		5,000
GSA Leases, Initial Lease Term		10 years
GSA Leases, Renewal Term		5 years
HC Government Realty Trust, Inc [Member] | Maximum [Member]
Rentable Area of Each GSA Property Invested In | ft²		50,000
GSA Leases, Initial Lease Term		20 years
GSA Leases, Renewal Term		10 years
HC Government Realty Trust, Inc [Member] | Series B Cumulative Convertible Preferred Stock [Member]
Investment, Shares Purchased During Period	200,000
Preferred Stock, Dividend Rate, Percentage	10.00%
Equity Method Investment, Aggregate Cost | $	$ 2,000,000
Convertible Preferred Stock of Investee, Shares Issued Upon Conversion		1
Convertible Preferred Stock, Maximum Conversion Price | $ / shares		$ 9.10
HC Government Realty Trust, Inc [Member] | Series B Cumulative Convertible Preferred Stock [Member] | Investors Affiliated with the Hale Partnership [Member]
Investment, Shares Purchased During Period	850,000
Equity Method Investment, Aggregate Cost | $	$ 8,500,000
HC Government Realty Trust, Inc [Member] | Common Stock of Investee [Member]
Investment, Shares Purchased During Period	300,000
Equity Method Investment, Aggregate Cost | $	$ 3,000,000
HC Government Realty Trust, Inc [Member] | Common Stock of Investee [Member] | Investors Affiliated with the Hale Partnership [Member]
Investment, Shares Purchased During Period	850,000