Note 5 - Other Real Estate Investments (Details Textual)	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Equity Method Investments		$ 509,448,000		$ 509,448,000		$ 504,209,000
Income (Loss) from Equity Method Investments		9,100,000	$ 11,500,000	37,044,000	$ 190,155,000
Proceeds from Equity Method Investment, Distribution, Return of Capital					190,102,000
Preferred Equity Investments [Member]
Equity Method Investments		$ 357		357
Income (Loss) from Equity Method Investments				27,200,000	22,300,000
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax				$ 14,800,000
Equity Method Investment, Realized Gain (Loss) on Disposal					$ 10,100,000
Number of Capital Transactions			4		4
Preferred Equity Investments [Member] | Leased Properties [Member]
Number of Real Estate Properties		345		345
Preferred Equity Investments [Member] | Maximum Exposure [Member]
Equity Method Investments		$ 198,100,000		$ 198,100,000
AB Acquisition [Member] | ABS Venture [Member]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		14.35%		14.35%
AB Acquisition [Member] | Kimco [Member]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		9.80%		9.80%
Albertsons [Member]
Proceeds from Equity Method Investment, Distribution, Return of Capital	$ 23,700,000
Albertsons [Member] | ABS Venture [Member]
Proceeds from Equity Method Investment, Distribution, Return of Capital	34,600,000
Albertsons [Member] | Noncontrolling Interest Members in ABS Venture [Member]
Proceeds from Equity Method Investment, Distribution, Return of Capital	$ 10,900,000