Note 6 - Other Real Estate Investments and Other Assets (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Equity Method Investments	$ 580,737		$ 580,737		$ 483,861
Income (Loss) from Equity Method Investments, Total	$ 16,500	$ 9,100	$ 52,486	$ 37,044
Preferred Equity Investments [Member]
Number of Real Estate Properties	285		285
Income (Loss) from Equity Method Investments, Total			$ 24,400
Equity Method Investment, Realized Gain (Loss) on Disposal, Total			$ 10,500
Preferred Equity Investments [Member] | Leased Properties [Member]
Number of Real Estate Properties	273		273
Preferred Equity Investments [Member] | Maximum Exposure [Member]
Equity Method Investments	$ 175,200		$ 175,200
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