Note 3 - Real Estate - Disposition Activity (Details) - Disposition Activity Relating to Consolidated Operating Properties and Parcels [Member] $ in Millions		1 Months Ended	6 Months Ended
		May 31, 2021	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)
Aggregate sales price			$ 132.2	$ 17.2
Gain on sale of properties (1)	[1]		$ 28.9	$ 5.7
Number of properties sold		2	3	3
Number of parcels sold			7	0

[1] Before noncontrolling interests of $3.1 million and taxes of $2.1 million, after utilization of net operating loss carryforwards, for the six months ended June 30, 2021.