Amount incurred in debt origination and legal costs.

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Namespace Prefix:	krc
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount incurred in debt origination and legals costs.

+ Details

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Namespace Prefix:	krc
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Average Trading Price of the Company's Stock.

+ Details

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Namespace Prefix:	krc
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Amortization Period in Number of Years.

+ Details

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Namespace Prefix:	krc
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Exchange price of exchangeable notes including effect of capped calls.

+ Details

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Namespace Prefix:	krc
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair value of the shares upon conversion if Exchangeable Notes were converted on specified date.

+ Details

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Namespace Prefix:	krc
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Additional borrowing capacity under the Credit Facility, subject to bank approval.

+ Details

Name:	krc_LineOfCreditFacilityAdditionalBorrowingCapacity
Namespace Prefix:	krc
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Secured and Unsecured Debt of the Operating Partnership Textuals Abstract.

+ Details

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Namespace Prefix:	krc
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ Details

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Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date before deducting unamortized discount or premiums (if any). May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ 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 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Paragraph 31
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 20
-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 16
-Article 9

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031898-161870

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number APB14-1
-Paragraph 32
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

- Definition

The amount by which the convertible debt's if-converted value exceeds its principle amount at the balance sheet date, regardless of whether the instrument is currently convertible. This element applies to public companies only.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031898-161870

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-Publisher FASB
-Name FASB Staff Position (FSP)
-Number APB14-1
-Paragraph 32
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 21
-Paragraph 16, 20
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

+ Details

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

- Definition

Interest rate stated in the contractual debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

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(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

Date when the debt instrument is scheduled to be fully repaid, which may be presented in a variety of ways (year, month and year, day, month and year, quarter, etc.).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

Reference 3: 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(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of debt premium that was originally recognized at the issuance of the instrument that has yet to be amortized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 21
-Paragraph 16, 20
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

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

- Definition

The number of real estate properties owned as of the balance sheet date.

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Secured and Unsecured Debt of the Operating Partnership (Details 3) (USD $)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010
Secured and Unsecured Debt of the Operating Partnership (Textuals) (Abstract)
Maturity Date			Nov. 15, 2014
Annual interest rate (mortgage loan)				3.25%
Number of Buildings	8	8
Exchange price per share average trading price	$ 35.93	$ 35.93		$ 35.93
Average Trading Price of the Company's Stock	$ 39.90	$ 38.94
Operating Partnership [Member]
Secured and Unsecured Debt of the Operating Partnership (Textuals) (Abstract)
Principal amount	$ 1,698,791,000	$ 1,698,791,000
Additional line of credit under Credit Facility		200,000,000
Credit facility spread	1.75%	1.75%	2.675%
Operating Partnership [Member] \| 3.25% Exchangeable Notes [Member]
Secured and Unsecured Debt of the Operating Partnership (Textuals) (Abstract)
Annual interest rate (mortgage loan)	3.25%	3.25%	3.25%
Exchange price including effect of capped calls	102.72	102.72	102.72
Operating Partnership [Member] \| 4.25% Exchangeable Notes [Member]
Secured and Unsecured Debt of the Operating Partnership (Textuals) (Abstract)
Annual interest rate (mortgage loan)	4.25%	4.25%	4.25%
Principal amount	172,500,000	172,500,000
Exchange price including effect of capped calls	42.81	42.81	42.81
Fair value of the shares upon conversion if Exchangeable Notes were converted on specified date	191,400,000	191,400,000
Amount by which fair value of the shares upon conversion exceeds principal amount of the Exchangeable Notes on the specified date		18,900,000
Operating Partnership [Member] \| 4.94%Mortgage Payable due April 15, 2015 [Member]
Secured and Unsecured Debt of the Operating Partnership (Textuals) (Abstract)
Number of Buildings	4	4
New Amendment to Credit Facility [Member]
Secured and Unsecured Debt of the Operating Partnership (Textuals) (Abstract)
Amount incurred in debt origination and legals costs		3,300,000
Prior Credit Facility [Member]
Secured and Unsecured Debt of the Operating Partnership (Textuals) (Abstract)
Amount incurred in debt origination and legal costs		5,000,000
4.27% Mortgage Payable due Feb 1, 2018 [Member]
Secured and Unsecured Debt of the Operating Partnership (Textuals) (Abstract)
Principal amount of unsecured senior notes	135,000,000	135,000,000
Maturity Date		Feb. 01, 2018
Annual interest rate (mortgage loan)	4.27%	4.27%
Debt Amortization Period in Number of Years		30
4.94% Mortgage Payable due April 15, 2015 [Member]
Secured and Unsecured Debt of the Operating Partnership (Textuals) (Abstract)
Principal amount of unsecured senior notes	30,000,000	30,000,000
Maturity Date		Apr. 15, 2015
Annual interest rate (mortgage loan)	4.94%	4.94%
Debt Amortization Period in Number of Years		30
Debt premium	$ 1,000,000	$ 1,000,000