Commitments and Contingencies (Details 1) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013
Commitments and Contingencies (Textuals) [Abstract]
Commitments for contracts and executed leases, operating and redevelopment and development properties	$ 529.6
Maximum [Member]
Commitments and Contingencies (Textuals) [Abstract]
Purchase Option, Maximum Price	$ 27.5

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