Note 6 - Disposition Activities - Real Estate Purchase and Sale Agreements (Details) - Port Jefferson Professional Park [Member] - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Proceeds from property sold	$ 2,800,000	$ 4,246,000
The 5380 Nesconset Highway [Member]
Proceeds from property sold	2,000,000
Property at 1 Medical Drive, Port Jefferson Station, New York [Member]
Proceeds from property sold	800,000
Property at 6 Medical Drive [Member]
Proceeds from property sold		850,000
Property at 8 Medical Drive [Member]
Proceeds from property sold		820,000
Property at 4 Medical Drive [Member]
Proceeds from property sold		900,000
Property at 3 Medical Drive [Member]
Proceeds from property sold		876,000
Property at 2 Medical Drive [Member]
Proceeds from property sold		$ 800,000