Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) $ in Thousands, CAD in Millions				3 Months Ended		9 Months Ended
		Oct. 06, 2015 USD ($)	Oct. 06, 2015 CAD	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Feb. 28, 2015	Dec. 31, 2014	Sep. 30, 2013 USD ($)
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Business Combination, Consideration Transferred						$ 1,554,744
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt				$ 166		166
Gains (Losses) on Sales of Investment Real Estate						86,200
Impairment of Real Estate						2,200
Income (Loss) from Equity Method Investments						130,808	$ 150,073
Proceeds from Sale of Real Estate						276,300
Operating Properties [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Income (Loss) from Equity Method Investments						$ 15,400
Subsequent Event [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Sales of Real Estate		$ 366,100
Sales [Member] | Subsequent Event [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Sales of Real Estate | CAD			CAD 477.3
KimPru and KimPru II [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Number of Joint Ventures				4		4
Number of Accounts				4		4
Number of Real Estate Properties	[1],[2]			55		55			60
Income (Loss) from Equity Method Investments	[3]			$ (200)	$ 2,600	$ 3,300	7,700
KimPru [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Number of Joint Ventures				3		3
Intown [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Deferred Gain on Sale of Property										$ 21,700
Gains (Losses) on Sales of Investment Real Estate						$ 21,700
Other Joint Venture Programs [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Number of Real Estate Properties				53		53			60
Income (Loss) from Equity Method Investments	[4],[5],[6]			$ (5,500)	27,200	$ 15,900	52,300
Other Joint Venture Programs [Member] | Partially Owned Properties [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Impairment of Real Estate						9,800
KIR [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Income (Loss) from Equity Method Investments	[7]			$ 8,500	6,500	$ 31,600	19,400
Other Institutional Programs [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Number of Real Estate Properties	[1]			53		53			53
Income (Loss) from Equity Method Investments				$ 100	$ 2,600	$ 400	4,000
Other Institutional Programs [Member] | Acquired [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Number of Real Estate Properties				25		25
Properties and Land Parcels, Joint Ventures [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Gains (Losses) on Sales of Investment Real Estate						$ 61,700	$ 59,500
Canadian Properties [Member] | Subsequent Event [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Number of Real Estate Properties		19	19
Sales of Real Estate		$ 97,000	CAD 126.5
Proceeds from Sale of Real Estate		$ 224,000	CAD 291.9
Kimstone [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired				66.70%		66.70%
Number of Real Estate Properties				39		39		39
Business Combination, Consideration Transferred	[8]					$ 1,387,500
Kimstone [Member] | Mortgages [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt				$ 638,000		$ 638,000
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | KIR [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Number of Real Estate Properties				2		2
Impairment of Real Estate						$ 2,800
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | KIR [Member]
Note 4 - Investment and Advances in Real Estate Joint Ventures (Details) [Line Items]
Impairment of Real Estate						$ 5,000

[1] The Company manages these joint venture investments and, where applicable, earns acquisition fees, leasing commissions, property management fees, assetmanagement fees and construction management fees.

[2] This venture represents four separate joint ventures, with four separate accounts managed by Prudential Real Estate Investors ("PREI"), three of these ventures are collectively referred to as KimPru and the remaining venture is referred to as KimPru II.

[3] During the nine months ended September 30, 2015, KimPru recognized aggregate impairment charges related to three properties which KimPru anticipates selling or being foreclosed on within the next year, therefore effectively shortening its anticipated hold period for these assets which resulted in the expected future cash flows being less than the carrying value. The Company's share of these impairment charges was $2.8 million.

[4] During September 2013, the Intown portfolio was sold and the Company maintained its guarantee on a portion of debt that was assumed by the buyer atclosing. The transaction resulted in a deferred gain to the Company of $21.7 million due to the Company's continued involvement through its guarantee of thedebt. On February 24, 2015, the outstanding debt balance was fully repaid by the buyer and as such, the Company was relieved of its related commitments and guarantee. As a result, the Company recognized the deferred gain of $21.7 million during the nine months ended September 30, 2015.

[5] During the nine months ended September 30, 2014, the Company received a distribution of $15.4 million from a joint venture that was in excess of its carrying value and as such, the Company recognized this amount as equity in income.

[6] During the nine months ended September 30, 2015, three joint ventures in which the Company holds noncontrolling interests recognized impairment charges relating to the pending sale of two properties and the pending foreclosure of one property. The Company's share of these impairment charges was $9.8 million, before income tax benefit.

[7] During the nine months ended September 30, 2014, KIR recognized aggregate impairment charges of $5.0 million, of which the Company's share was $2.8 million, related to two properties which KIR anticipates selling within the next year, therefore effectively shortening its anticipated hold period for these assets which resulted in the expected future cash flows being less than the carrying value.

[8] The Company acquired from its partner the remaining ownership interest in 39 properties that were held in a joint venture in which the Company had a 33.3%noncontrolling interest. The Company evaluated this transaction pursuant to the FASB's Consolidation guidance and as a result, recognized a gain on change in control of interest of $140.0 million resulting from the fair value adjustment associated with the Company's previously held equity interest, which is reflected in the purchase price above in Other.