Note 4 - Real Estate - Disposition Activity (Details) - Disposition Activity Relating to Consolidated Operating Properties and Parcels [Member] $ in Millions		1 Months Ended	9 Months Ended
		Jun. 30, 2021	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)
Aggregate sales price			$ 156.6	$ 22.6
Gain on sale of properties	[1]		$ 30.8	$ 5.7
Number of properties sold		2	5	3
Number of parcels sold			9	1

[1] Before noncontrolling interests of $3.0 million and taxes of $2.2 million, after utilization of net operating loss carryforwards, for the nine months ended September 30, 2021.