Note 4 - Investments and Advances in Real Estate Joint Ventures - Summary of Properties and Land Parcels Disposed of (Details) $ in Millions		6 Months Ended
		Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)
Kim Pru and Kim Pru II [Member]
Number of Properties		1	1
Number of Land Parcels
Aggregate Sales Price		$ 16.5	$ 23.2
KIR [Member]
Number of Properties		1	3
Number of Land Parcels
Aggregate Sales Price		$ 23.6	$ 48.0
CPP [Member]
Number of Properties	[1]	2
Number of Land Parcels	[1]
Aggregate Sales Price	[1]	$ 299.2
Other Joint Venture Programs [Member]
Number of Properties		2	1	[2]
Number of Land Parcels				[2]
Aggregate Sales Price		$ 21.6	$ 5.8	[2]
Canadian Properties [Member]
Number of Properties		29	3
Number of Land Parcels			1
Aggregate Sales Price		$ 797.3	$ 190.7

[1] In April 2016, the Company acquired its partner's interest in an operating property and a development project for a gross purchase price of $299.2 million, including the assumption of $100.0 million in mortgage debt, which encumbered the operating property.

[2] The Company acquired the remaining interest in this property during the six months ended June 30, 2015.