Note 6 - Other Real Estate Investments and Other Assets (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Equity Method Investments	$ 568,698		$ 568,698		$ 483,861
Income (Loss) from Equity Method Investments, Total	$ 19,000	$ 13,200	$ 35,953	$ 27,902
Preferred Equity Investments [Member]
Number of Real Estate Properties	286		286
Income (Loss) from Equity Method Investments, Total			$ 19,500
Equity Method Investment, Realized Gain (Loss) on Disposal, Total			$ 10,000
Preferred Equity Investments [Member] | Leased Properties [Member]
Number of Real Estate Properties	273		273
Preferred Equity Investments [Member] | Maximum Exposure [Member]
Equity Method Investments	$ 172,100		$ 172,100
Albertstons Companies, Inc. [Member]
Percentage of Ownership	9.74%		9.74%
Albertstons Companies, Inc. [Member] | Other Assets [Member]
Other Investments, Total	$ 140,200		$ 140,200