Partners' Capital of the Operating Partnership (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
General Partners' Capital Account [Abstract]
Net proceeds from issuance of common stock	$ 113,097	$ 0
Noncontrolling Interest, Ownership Percentage by Parent	98.00%	97.90%	98.00%
Common units held by limited partners	1,793,170	1,804,200	1,804,200
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	2.00%	2.10%	2.00%
Kilroy Realty, L.P. [Member] \| Capital Units [Member]
General Partners' Capital Account [Abstract]
General Partners' Capital Account, Units Outstanding	88,031,377	82,218,332	86,259,684

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The number of general partner units outstanding.

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The number of limited partner units outstanding.

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

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No definition available.

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The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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No definition available.

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The cash inflow from the additional capital contribution to the entity.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Glossary Financing Activities

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