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, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 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	$ 919.2		$ 920.0
Average Interest Rate	5.53%		5.53%
Average Remaining Term	20 months 3 days	[1]	23 months	[1]
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	862.6		860.7
Average Interest Rate	4.92%		5.04%
Average Remaining Term	66 months 27 days	[1]	61 months 27 days	[1]
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			28 months 21 days	[1]
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	144.8		144.6
Average Interest Rate	5.51%		5.52%
Average Remaining Term	19 months 3 days	[1]	22 months	[1]
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	111.5		112.0
Average Interest Rate	5.07%		5.05%
Average Remaining Term	12 months 15 days	[1]	10 months 3 days	[1]
SEB Immobilien [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	50.0		50.0
Average Interest Rate	4.07%		4.06%
Average Remaining Term	32 months 21 days	[1]	35 months 21 days	[1]
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	222.6		222.9
Average Interest Rate	5.47%		5.47%
Average Remaining Term	17 months 24 days	[1]	20 months 24 days	[1]
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	545.9		640.5
Average Interest Rate	4.23%		4.29%
Average Remaining Term	36 months 27 days	[1]	39 months 27 days	[1]
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	888.7		921.9
Average Interest Rate	5.37%		5.31%
Average Remaining Term	55 months 6 days	[1]	58 months 18 days	[1]
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	$ 3,745.3		$ 4,573.9

[1] Average Remaining Term includes extension options.