Note 3 - Real Estate - Disposition Activity (Details) - Disposition Activity Relating to Consolidated Operating Properties and Parcels [Member] $ in Millions		6 Months Ended
		Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)
Aggregate sales price (1)	[1]	$ 17.2	$ 110.1
Gain on sale of properties		$ 5.7	$ 38.4
Number of properties sold		3	7
Number of out-parcels sold		0	5

[1] During the six months ended June 30, 2020, the Company held in escrow an aggregate of $3.2 million of net proceeds in connection with these sales associated with a reverse exchange in accordance with Internal Revenue Code 26 U.S.C.1031, which was returned to the Company in July 2020.