Note 5 - Other Real Estate Investments (Details Textual) - Preferred Equity Investments [Member] $ in Millions	3 Months Ended
Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)
Equity Method Investments	$ 99.4
Number of Real Estate Properties	111
Income (Loss) from Equity Method Investments, Total	$ 3.2	$ 11.1
Equity Method Investment, Realized Gain (Loss) on Disposal, Total		$ 6.3
Leased Properties [Member]
Number of Real Estate Properties	101

Amount of income (loss) for proportionate share of equity method investee's income (loss).

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