Stockholders' Equity of the Company - At-The-Market Offering and Derivatives and Distributions (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Dividends and Distributions payable to:
Accrued distributions (Notes 15 and 26)	$ 64,440	$ 64,285
Outstanding Shares and Units:
Common stock (in shares)	117,239,558	116,878,031
Restricted Stock Units (RSUs)
Outstanding Shares and Units:
RSUs (in shares)	908,336	984,006
Kilroy Realty L.P.
Dividends and Distributions payable to:
Accrued distributions (Notes 15 and 26)	$ 64,440	$ 64,285
Kilroy Realty L.P. | Restricted Stock Units (RSUs)
Dividends and Distributions payable to:
Accrued distributions (Notes 15 and 26)	$ 510	$ 550
Kilroy Realty L.P. | Market measure-based Restricted Stock Units (RSUs)
Outstanding Shares and Units:
Number of RSUs outstanding (in shares)	1,083,086	1,123,554
Kilroy Realty L.P. | Common Units
Outstanding Shares and Units:
Noncontrolling common units ( in shares )	1,150,574	1,150,574
Noncontrolling common units | Common Units
Outstanding Shares and Units:
Noncontrolling common units ( in shares )	1,150,574	1,150,574
Common stockholders and noncontrolling unitholders
Dividends and Distributions payable to:
Accrued distributions (Notes 15 and 26)	$ 64,440	$ 64,285
Common stockholders
Dividends and Distributions payable to:
Accrued distributions (Notes 15 and 26)	$ 63,309	$ 63,114
Outstanding Shares and Units:
Common stock (in shares)	117,239,558	116,878,031
Common Units
Dividends and Distributions payable to:
Accrued distributions (Notes 15 and 26)	$ 621	$ 621