Secured and Unsecured Debt of the Operating Partnership - Capitalized Interest and Loan Fees (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Capitalized Interest and Loan Fees [Line Items]
Interest expense	$ 20,625	$ 22,334
Kilroy Realty L.P.
Capitalized Interest and Loan Fees [Line Items]
Gross interest expense	39,723	39,242
Capitalized interest and deferred financing costs	(19,098)	(16,908)
Interest expense	$ 20,625	$ 22,334