Note 3 - Real Estate - Disposition Activity (Details) - Disposition Activity Relating to Consolidated Operating Properties and Parcels [Member] $ in Millions	3 Months Ended
Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)
Aggregate sales price	$ 13.5	$ 74.2
Gain on sale of properties	$ 3.8	$ 23.6
Number of properties sold	1	5
Number of out-parcels sold	0	2

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

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