CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	280,000,000	280,000,000
Common stock, shares issued (in shares)	116,464,169	116,035,827
Common stock, shares outstanding (in shares)	116,464,169	116,035,827
Noncontrolling common unitholders of the Operating Partnership | Kilroy Realty L.P.
General partner, units issued (in shares)	116,464,169	116,035,827
General partner, units outstanding (in shares)	116,464,169	116,035,827
Limited partner, units issued (in shares)	1,150,574	1,150,574
Limited partner, units outstanding (in shares)	1,150,574	1,150,574