Note 5 - Other Real Estate Investments (Details Textual) - Preferred Equity Investments [Member] $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)
Equity Method Investments	$ 159.6
Number of Real Estate Properties	205
Income (Loss) from Equity Method Investments, Total	$ 11.1	$ 6.5
Equity Method Investment, Realized Gain (Loss) on Disposal, Total	$ 6.3	$ 1.0
Leased Properties [Member]
Number of Real Estate Properties	195