Commitments and Contingencies (Details 1) (USD $) In Millions, unless otherwise specified		3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2013 Maximum [Member]	Sep. 30, 2013 Former Tenant Litigation Case [Member]	Sep. 30, 2013 Property Damage Litigation Case [Member]
Long-term Purchase Commitment [Line Items]
Commitments for contracts and executed leases, operating and redevelopment and development properties	$ 447.7
Purchase Option, Maximum Price		27.5
Proceeds from Legal Settlements			$ 3.7	$ 5.2

Operating amounts represent commitments under signed leases and contracts for operating properties, excluding tenant-funded tenant improvements. Redevelopment/development amounts represent contractual commitments for redevelopment or development contracts and projects under construction. Redevelopment costs include the remaining total estimated investment, excluding capitalized interest, development overhead, potential future leasing costs, and tenant improvements for these projects.

No definition available.

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