Debt Instrument, Contingent Additional Borrowings

No definition available.

Name:	krc_DebtInstrumentContingentAdditionalBorrowings
Namespace Prefix:	krc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of debt issuance costs that were incurred during a noncash or partial noncash transaction.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Period Type:	instant

- Definition

Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3291-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The percentage rate used to calculate dividend payments on preferred stock.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The redemption (or callable) amount of currently redeemable preferred stock. Includes amounts representing dividends not currently declared or paid but which will be payable under the redemption features or for which ultimate payment is solely within the control of the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.27(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The price per share at which the preferred stock of an entity that has priority over common stock in the distribution of dividends and in the event of liquidation of the entity is redeemed or may be called at. The redemption features of this preferred stock are solely within the control of the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

+ References

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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- Details

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- Details

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- Details

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- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=krc_OneHundredFiftyMillionTermLoanFacilityMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

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- Details

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Subsequent Events (Details) - USD ($)				6 Months Ended		12 Months Ended
Subsequent Events (Details) - USD ($)	Aug. 15, 2017	Jul. 12, 2017	Jan. 13, 2017	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Jul. 24, 2017
Subsequent Event [Line Items]
Payment of special dividend			$ 36,400,000	$ 255,292,000	$ 65,935,000
Unsecured debt, net (Notes 5 and 11)				$ 2,097,083,000		$ 1,847,351,000
Subsequent event [Member]
Subsequent Event [Line Items]
Payment of special dividend		$ 43,300,000
Series H Cumulative Redeemable Preferred Stock [Member]
Subsequent Event [Line Items]
Preferred stock, redeemed (in shares)				4,000,000		4,000,000
Preferred stock dividend rate percentage				6.375%		6.375%
Series H Cumulative Redeemable Preferred Stock [Member] \| Subsequent event [Member]
Subsequent Event [Line Items]
Preferred stock, redeemed (in shares)		4,000,000
Series H Cumulative Redeemable Preferred Stock [Member] \| Scenario, forecast [Member]
Subsequent Event [Line Items]
Preferred stock, redemption price (in dollars per share)	$ 25.00
Preferred stock, redemption amount	$ 100,000,000
Debt issuance costs incurred during noncash transaction	$ 3,700,000
Kilroy Realty, L.P. [Member]
Subsequent Event [Line Items]
Payment of special dividend				$ 255,292,000	$ 65,935,000
Unsecured debt, net (Notes 5 and 11)				2,097,083,000		$ 1,847,351,000
Kilroy Realty, L.P. [Member] \| Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Total borrowing capacity				600,000,000		600,000,000
Contingent additional borrowings				311,000,000
Kilroy Realty, L.P. [Member] \| Revolving Credit Facility [Member] \| Subsequent event [Member]
Subsequent Event [Line Items]
Total borrowing capacity							$ 750,000,000.0
$150 Million Term Loan Facility [Member] \| Kilroy Realty, L.P. [Member] \| Line of Credit [Member]
Subsequent Event [Line Items]
Unsecured debt, net (Notes 5 and 11)				150,000,000		150,000,000
$39 Million Unsecured Term Loan [Member] \| Kilroy Realty, L.P. [Member] \| Line of Credit [Member]
Subsequent Event [Line Items]
Unsecured debt, net (Notes 5 and 11)				$ 39,000,000		$ 39,000,000