Note 3 - Operating Property Activities - Disposition Activity (Details) $ in Millions	9 Months Ended
Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Gain on sale of properties/change in control of interests	$ 47.4	$ 180.5
Disposition Activity Relating to Consolidated Operating Properties and Parcels [Member]
Aggregate sales price/gross fair value	$ 163.8	$ 973.5
Number of operating properties sold/deconsolidated	12	45
Number of out-parcels sold	7	4

Amount after tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

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