Note 4 - Investments in and Advances to Real Estate Joint Ventures - Joint Venture Investments Accounted for Under the Equity Method, Debt Details (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Mar. 31, 2017	Dec. 31, 2016
Mortgage and notes payable		$ 1,948.6	$ 2,063.0
Kim Pru and Kim Pru II [Member]
Mortgage and notes payable		$ 629.3	$ 647.4
Weighted average interest rate		2.85%	3.07%
Weighted average remaining term (Month)	[1]	5 years 189 days	5 years 225 days
KIR [Member]
Mortgage and notes payable		$ 737.5	$ 746.5
Weighted average interest rate		4.58%	4.64%
Weighted average remaining term (Month)	[1]	4 years 141 days	4 years 207 days
CPP [Member]
Mortgage and notes payable		$ 84.9	$ 84.8
Weighted average interest rate		2.33%	2.17%
Weighted average remaining term (Month)	[1]	1 year 30 days	1 year 120 days
Other Joint Venture Programs [Member]
Mortgage and notes payable		$ 496.9	$ 584.3
Weighted average interest rate		5.38%	5.40%
Weighted average remaining term (Month)	[1]	1 year 357 days	1 year 342 days

[1] Average Remaining Term includes extension options.