Note 3 - Real Estate - Disposition Activity (Details) - Disposition Activity Relating to Consolidated Operating Properties and Parcels [Member] $ in Millions		3 Months Ended
		Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)
Aggregate sales price		$ 23.0	$ 13.5
Gain on sale of properties (1)	[1]	$ 10.0	$ 3.8
Number of properties sold		1	1
Number of parcels sold		4	0

[1] Before noncontrolling interests of $3.0 million and taxes of $1.0 million for the three months ended March 31, 2021.