KW Unsecured Debt - Senior Notes (Details) - Senior Notes [Member]	Mar. 31, 2020 USD ($)
Maximum [Member]
Debt Instrument [Line Items]
Balance sheet leverage ratio	1.50
Balance sheet leverage at period end	0.72
5.875% Percent Senior Notes Due 2024 [Member]
Debt Instrument [Line Items]
Debt face value	$ 1,150,000,000.0
Interest rate (as a percent)	5.875%

Debt Instrument, Covenant, Balance Sheet Leverage

No definition available.

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Namespace Prefix:	kw_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Balance Sheet Leverage at Period End

+ References

No definition available.

+ Details

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Namespace Prefix:	kw_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Balance Type:	na
Period Type:	instant

- 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.

+ Details

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Period Type:	duration

- Details

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- Details

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- Details

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