Secured and Unsecured Debt of the Operating Partnership - Capitalized Interest and Loan Fees (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Capitalized Interest and Loan Fees [Line Items]
Interest expense	$ 19,982	$ 16,105	$ 60,728	$ 59,829
Kilroy Realty L.P.
Capitalized Interest and Loan Fees [Line Items]
Gross interest expense	39,659	39,552	118,995	118,257
Capitalized interest and deferred financing costs	(19,677)	(23,447)	(58,267)	(58,428)
Interest expense	$ 19,982	$ 16,105	$ 60,728	$ 59,829