Investments in real estate Schedule of investment in real estates (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Real Estate Properties [Line Items]
Investments in real estate	$ 10,671,227	$ 10,298,019
North America
Real Estate Properties [Line Items]
Land (related to rental properties)	1,403,659	1,312,072
Buildings and building improvements	9,219,013	9,000,626
Other improvements	845,772	780,117
Rental properties	11,468,444	11,092,815
Development and redevelopment projects (under construction or pre-construction)	1,044,377	955,218
Future development projects	96,813	96,112
Gross investments in real estate	12,609,634	12,144,145
Less: accumulated depreciation	(1,969,084)	(1,875,810)
Investments in real estate	10,640,550	10,268,335
Asia
Real Estate Properties [Line Items]
Investments in real estate	$ 30,677	$ 29,684

Carrying amount as of the balance sheet date of improvements not otherwise specified in the existing taxonomy.

No definition available.

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- Definition

The current amount of expenditures for a real estate project that has not yet been completed.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.10)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Phase
-URI http://asc.fasb.org/extlink&oid=49177889

+ Details

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- Definition

Aggregate of the carrying amounts as of the balance sheet date of investments in building and building improvements.

+ References

+ Details

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- Definition

Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 4
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6812-107765

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.13)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Carrying amount of land available for development.

+ References

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- Definition

The cumulative amount of depreciation for real estate property held for investment purposes.

+ References

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- Definition

Amount of real estate investment property which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

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- Definition

Amount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Carrying amount of income producing properties held for rental.

+ References

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