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Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature.

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Percentage investment held by members or limited partners of limited liability company (LLC) or limited partnership (LP).

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The number of limited partner units outstanding.

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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.

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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Portion of equity (net assets) in a variable interest entity (VIE) not attributable, directly or indirectly, to the parent entity. That is, this is the portion of equity in a VIE that is attributable to the noncontrolling interest (previously referred to as minority interest).

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Noncontrolling Interests on the Company’s Consolidated Financial Statements (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) trading_day $ / shares shares	Dec. 31, 2022 USD ($) trading_day $ / shares shares	Aug. 30, 2016 rEITSubsidiary company
Noncontrolling Interest [Line Items]
Conversion ratio	1
Common stock, par value ( in dollars per share) \| $ / shares	$ 0.01	$ 0.01
Number of trading days \| trading_day	10	10
Aggregate value upon redemption of outstanding noncontrolling common units	$ 47,000	$ 44,700
Noncontrolling interest in consolidated subsidiary	$ 178,257	$ 184,390
Non-Affiliated Investors and Certain Executive Officer and Directors \| Common Units
Noncontrolling Interest [Line Items]
Noncontrolling common units ( in shares ) \| shares	1,150,574	1,150,574
Kilroy Realty L.P. \| Common Units
Noncontrolling Interest [Line Items]
Conversion ratio	1
Kilroy Realty L.P. \| Common Units
Noncontrolling Interest [Line Items]
Noncontrolling common units ( in shares ) \| shares	1,150,574	1,150,574
Operating Partnership
Noncontrolling Interest [Line Items]
Ownership interest (percent)	99.00%	99.00%
Operating Partnership \| Non-Affiliated Investors and Certain Executive Officer and Directors
Noncontrolling Interest [Line Items]
Ownership interest (percent)	1.00%	1.00%
Norges Bank Real Estate Management (NBREM) \| Consolidated property partnerships
Noncontrolling Interest [Line Items]
Contributions, number of REIT subsidiaries \| rEITSubsidiary			2
Ownership interest of limited partnership interests			44.00%
Ownership interest, number of existing companies \| company			2
100 First LLC and 303 Second LLC \| Variable Interest Entity, Primary Beneficiary
Noncontrolling Interest [Line Items]
Noncontrolling interest in consolidated subsidiary	$ 173,700	$ 179,400
Redwood LLC
Noncontrolling Interest [Line Items]
Noncontrolling interest in consolidated subsidiary	$ 4,600	$ 5,000