Note 10 - Variable Interest Entities (Details Textual) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)
Consolidated Operating Properties [Member]
Variable Interest Entity, Number of Entities	21
Variable Interest Entity, Consolidated, Carrying Amount, Assets	$ 902.0
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	174.2
Real Estate Under Development [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	183.1
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	$ 2.3
Number of Consolidated Entities	2
Variable Interest Entity, Financial or Other Support, Amount	$ 68.7
Redevelopment [Member]
Variable Interest Entity, Financial or Other Support, Amount	7.4
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 7.4