Consolidated Statements of Capital (KILROY REALTY, L.P.) (Kilroy Realty, L.P. [Member], USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended							3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Total Partners Capital [Member]	Mar. 31, 2011 Total Partners Capital [Member]	Mar. 31, 2012 Partners Capital Preferred Units [Member]	Mar. 31, 2011 Partners Capital Preferred Units [Member]	Dec. 31, 2010 Partners Capital Preferred Units [Member]	Mar. 31, 2012 Partners Capital Common Unit [Member]	Mar. 31, 2011 Partners Capital Common Unit [Member]	Mar. 31, 2012 Noncontrolling Interest In Consolidated Subsidiaries [Member]	Mar. 31, 2011 Noncontrolling Interest In Consolidated Subsidiaries [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ 1,327,482	$ 1,117,730	$ 1,324,841	$ 1,116,093	$ 121,582	$ 121,582	$ 121,582	$ 1,203,259	$ 994,511	$ 2,641	$ 1,637
Beginning Balance units								60,537,848	54,072,801
Net income	78,671	4,867	78,618	4,833				78,618	4,833	53	34
Issuance of Series G Preferred units (Note 9)	96,155		96,155		96,155
Redeemable Preferred Stock, Value, Excluding Distributions in Excess of Earnings					(121,582)
Original issuance costs of preferred stock called for redemption (Note 7)	(4,918)	0						(4,918)
Redeemable Preferred Stock, Value, Including Distributions in Excess of Earnings	(126,500)	0	(126,500)
Issuance of common units (Note 9)	382,063		382,063					382,063
Issuance of common units, units (Note 9)								9,487,500
Issuance of share-based compensation awards (Note 10)	294	1,875	294	1,875				294	1,875
Issuance of share-based compensation awards, units (Note 10)								59,938	66,208
Noncash amortization of share-based compensation (Note 10)	1,469	1,420	1,469	1,420				1,469	1,420
Repurchase of common units and restricted stock units (Note 10)	(603)	(732)	(603)	(732)				(603)	(732)
Repurchase of common units and restricted stock units, units (Note 10)								(22,312)	(11,485)
Exercise of stock options	129	395	129	395				129	395
Exercise of stock options, units								5,000	15,000
Other		0		1					1		(1)
Preferred distributions (Note 9)	(4,418)	(3,799)	(4,418)	(3,799)				(4,418)	(3,799)
Distributions declared per common unit ($0.35 per unit)	(24,892)	(19,233)	(24,892)	(19,233)				(24,892)	(19,233)
Ending Balance	$ 1,729,850	$ 1,102,523	$ 1,727,156	$ 1,100,853	$ 96,155	$ 121,582	$ 121,582	$ 1,631,001	$ 979,271	$ 2,694	$ 1,670
Ending Balance units								70,067,974	54,142,524