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Commitments and Contingencies - Additional Information (Detail) | 1 Months Ended | 6 Months Ended | 9 Months Ended |
--- | --- | --- | --- | ---
May 31, 2018 ft² yr | Jun. 30, 2018 ft² | Sep. 30, 2018 USD ($) | Dec. 31, 2017 USD ($)
Indemnification Obligation [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Litigation matters, liabilities | $ |  |  | $ 0 | $ 0
Kilroy Realty Finance Partnership, L.P [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Lease space | ft² | 135,936 |  |  |
Leased space delivered | ft² |  | 1,726 |  |
Lease term start year | 2018 |  |  |
Lease expiration year | 2030 |  |  |
Remaining square feet of space expected delivery period | fourth quarter of 2018 |  |  |
Remaining square feet of space expected delivery year | 2019 |  |  |
Lease expiration date | Jan. 31, 2030 |  |  |
Lease, option to extend, description | The lease term will end on January 31, 2030, subject to our right to extend the term of the Lease for a consecutive five-year period. |  |  |
Number of consecutive 5 year terms to extend lease | yr | 1 |  |  |
Lease extension term | 5 years |  |  |
Annual base rent of operating lease | $ |  |  | $ 10,900,000 |
Operating lease, annual rate of increase in rent |  |  | 3.00% |

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- Definition Number of consecutive five year terms to extend lease. + References No definition available. + Details
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- Definition Operating leases annual percentage increase in rent. + References No definition available. + Details
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- Definition Description of terms and conditions of option to extend lessee's operating lease. Includes, but is not limited to, information about option recognized as part of right-of-use asset and lease liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980 + Details
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