CONSOLIDATED STATEMENTS OF CAPITAL (KILROY REALTY, L.P.) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jan. 01, 2019
Dividends, Common Stock	$ 58,512	$ 49,315
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	45,418	41,794
Opening adjustment to Partners’ Capital upon adoption of ASC 842 (Note 1)			$ (3,146)
Non-cash amortization of share-based compensation (Note 7)	8,653	8,817
Settlement of restricted stock units	0	0
Distributions to noncontrolling interests in consolidated property partnerships	(2,617)	(6,309)
Noncontrolling Interests [Member]
Dividends, Common Stock	980	921
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	5,601	4,891
Distributions to noncontrolling interests in consolidated property partnerships	(2,617)	(6,309)
Kilroy Realty L.P. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	4,570,858	4,201,261
Net income	45,418	41,794
Opening adjustment to Partners’ Capital upon adoption of ASC 842 (Note 1)			(3,146)
Issuance of common units (Note 4)	721,794
Issuance of share-based compensation awards	1,720	2,210
Non-cash amortization of share-based compensation (Note 7)	8,653	8,817
Settlement of restricted stock units	0	0
Repurchase of common units, stock options and restricted stock units	(9,799)	(12,130)
Distributions to noncontrolling interests in consolidated property partnerships	(2,617)	(6,309)
Dividends declared per common unit	(58,512)	(49,315)
Ending balance	$ 5,277,515	$ 4,183,182
Kilroy Realty L.P. [Member] | Partners' Capital [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)	108,039,574	102,772,275
Beginning balance	$ 4,369,758	$ 4,003,700
Net income	$ 40,389	37,508
Opening adjustment to Partners’ Capital upon adoption of ASC 842 (Note 1)			$ (3,146)
Issuance of common units (in units)	8,897,110
Issuance of common units (Note 4)	$ 721,794
Issuance of share-based compensation awards	1,720	2,210
Non-cash amortization of share-based compensation (Note 7)	$ 8,653	$ 8,817
Settlement of restricted stock units (in units)	269,972	393,240
Repurchase of common units, stock options and restricted stock units (in units)	117,445	(175,204)
Repurchase of common units, stock options and restricted stock units	$ (9,799)	$ (12,130)
Dividends declared per common unit	$ (58,512)	$ (49,315)
Ending balance (in units)	117,089,211	102,990,311
Ending balance	$ 5,074,003	$ 3,987,644
Kilroy Realty L.P. [Member] | Noncontrolling Interests [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	201,100	197,561
Net income	5,029	4,286
Distributions to noncontrolling interests in consolidated property partnerships	(2,617)	(6,309)
Ending balance	$ 203,512	$ 195,538