Note 5 - Other Real Estate Investments (Details Textual) - Preferred Equity Investments [Member] $ in Millions	6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)
Equity Method Investments	$ 157.3
Number of Real Estate Properties	189
Income (Loss) from Equity Method Investments, Total	$ 15.9	$ 19.5
Equity Method Investment, Realized Gain (Loss) on Disposal, Total	$ 7.5	$ 9.8
Leased Properties [Member]
Number of Real Estate Properties	179