CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	280,000,000	280,000,000
Common stock, shares issued (in shares)	116,716,080	116,464,169
Common stock, shares outstanding (in shares)	116,716,080	116,464,169
Common Units | Kilroy Realty L.P.
General partner, units issued (in shares)	116,716,080	116,464,169
General partners, units outstanding (in shares)	116,716,080	116,464,169
Limited partners, units issued (in shares)	1,150,574	1,150,574
Limited partners, units outstanding (in shares)	1,150,574	1,150,574