Note 7 - Variable Interest Entities ("VIE") (Details Textual) $ in Millions	9 Months Ended
Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Variable Interest Entity, Number of Entities	24	27
Consolidated Operating Properties [Member]
Variable Interest Entity, Number of Entities	22	24
Variable Interest Entity, Consolidated, Carrying Amount, Assets, Total	$ 889.9	$ 1,200.0
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities, Total	$ 70.3	$ 383.5
Real Estate Under Development [Member]
Variable Interest Entity, Number of Entities	2	3
Variable Interest Entity, Consolidated, Carrying Amount, Assets, Total	$ 400.3	$ 307.9
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities, Total	73.1	$ 34.2
Real Estate Under Development, Project 1 [Member]
Variable Interest Entity, Financial or Other Support, Amount	150.0
Real Estate Under Development, Project 2 [Member]
Variable Interest Entity, Financial or Other Support, Amount	$ 200.0

Number of Variable Interest Entities for which the Company is the primary beneficiary.

No definition available.

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- Definition

The carrying amount of the consolidated Variable Interest Entity's assets included in the reporting entity's statement of financial position.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (bb)
-URI http://asc.fasb.org/extlink&oid=108788376&loc=d3e5710-111685

+ Details

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- Definition

The carrying amount of the consolidated Variable Interest Entity's liabilities included in the reporting entity's statement of financial position.

+ References

+ Details

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- Definition

The amount of financial or other support the reporting entity has provided (explicitly or implicitly) to the Variable Interest Entity (VIE) that it was not previously contractually required to provide or that the reporting entity intends to provide, including, for example, situations in which the reporting entity assisted the VIE in obtaining another type of support.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=108788376&loc=SL6759159-111685

+ Details

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- Details

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- Details

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- Details

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