REAL ESTATE AND ACQUIRED IN PLACE LEASE VALUE - Schedule of Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Real Estate [Abstract]
Pro forma revenues	$ 835.0	$ 740.2
Pro forma net income	150.1	99.5
Pro forma net income attributable to Kennedy-Wilson Holdings, Inc. common shareholders	$ 111.9	$ 24.8
Pro forma net income per share:
Basic (in dollars per share)	$ 0.94	$ 0.23
Diluted (in dollars per share)	$ 0.94	$ 0.23

Business Acquisition, Pro Forma Net Income (Loss) Available to Common Stockholders

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- Definition

The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)-(3)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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- Definition

The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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