Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) - Joint Venture Investments Accounted for under the Equity Method - Debt Details - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2015	Dec. 31, 2014
KimPru and KimPru II [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) - Joint Venture Investments Accounted for under the Equity Method - Debt Details [Line Items]
Mortgages and Notes Payable		$ 822.1	$ 920.0
Average Interest Rate		5.54%	5.53%
Average Remaining Term	[1]	15 months 15 days	23 months
KIR [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) - Joint Venture Investments Accounted for under the Equity Method - Debt Details [Line Items]
Mortgages and Notes Payable		$ 815.4	$ 860.7
Average Interest Rate		4.62%	5.04%
Average Remaining Term	[1]	65 months 9 days	61 months 27 days
Kimstone [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) - Joint Venture Investments Accounted for under the Equity Method - Debt Details [Line Items]
Mortgages and Notes Payable			$ 701.3
Average Interest Rate			4.45%
Average Remaining Term	[1]		28 months 21 days
BIG Shopping Centers [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) - Joint Venture Investments Accounted for under the Equity Method - Debt Details [Line Items]
Mortgages and Notes Payable		$ 119.9	$ 144.6
Average Interest Rate		5.45%	5.52%
Average Remaining Term	[1]	13 months 3 days	22 months
CPP [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) - Joint Venture Investments Accounted for under the Equity Method - Debt Details [Line Items]
Mortgages and Notes Payable		$ 110.5	$ 112.0
Average Interest Rate		5.15%	5.05%
Average Remaining Term	[1]	6 months 15 days	10 months 3 days
Other Institutional Programs [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) - Joint Venture Investments Accounted for under the Equity Method - Debt Details [Line Items]
Mortgages and Notes Payable		$ 216.8	$ 272.9
Average Interest Rate		5.28%	5.21%
Average Remaining Term	[1]	18 months 15 days	23 months 15 days
RioCan [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) - Joint Venture Investments Accounted for under the Equity Method - Debt Details [Line Items]
Mortgages and Notes Payable		$ 499.1	$ 640.5
Average Interest Rate		4.09%	4.29%
Average Remaining Term	[1]	37 months	39 months 27 days
Other Joint Venture Programs [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) - Joint Venture Investments Accounted for under the Equity Method - Debt Details [Line Items]
Mortgages and Notes Payable		$ 808.1	$ 921.9
Average Interest Rate		5.30%	5.31%
Average Remaining Term	[1]	49 months	58 months 18 days
All Equity Method Investments [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) - Joint Venture Investments Accounted for under the Equity Method - Debt Details [Line Items]
Mortgages and Notes Payable		$ 3,391.9	$ 4,573.9

[1] Average Remaining Term includes extension options.