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, 2013	Mar. 31, 2012	Mar. 31, 2013 Total Partners Capital [Member]	Mar. 31, 2012 Total Partners Capital [Member]	Mar. 31, 2012 Partners Capital Preferred Units [Member]	Mar. 31, 2013 Partners Capital Preferred Units [Member]	Dec. 31, 2012 Partners Capital Preferred Units [Member]	Mar. 31, 2013 Partners Capital Common Unit [Member]	Mar. 31, 2012 Partners Capital Common Unit [Member]	Mar. 31, 2013 Noncontrolling Interest In Consolidated Subsidiaries [Member]	Mar. 31, 2012 Noncontrolling Interest In Consolidated Subsidiaries [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ 2,235,933	$ 1,327,482	$ 2,232,654	$ 1,324,841	$ 121,582	$ 192,411	$ 192,411	$ 2,040,243	$ 1,203,259	$ 3,279	$ 2,641
Beginning Balance units								76,753,484	60,537,848
Net income	2,388	78,671	2,319	78,618				2,319	78,618	69	53
Issuance of Series G Preferred units		96,155		96,155	96,155
Redemption of Series E and Series F Preferred stock, shares					(121,582)
Redemption of Series E and Series F Preferred units		(126,500)		(126,500)					(4,918)
Issuance of common units, units (Note 8)								453,679	9,487,500
Issuance of common units (Note 8)	23,395	382,063	23,395	382,063				23,395	382,063
Issuance of share-based compensation awards, units (Note 9)								0	59,938
Issuance of share-based compensation awards (Note 9)	336	294	336	294				336	294
Noncash amortization of share-based compensation (Note 9)	2,422	1,469	2,422	1,469				2,422	1,469
Repurchase of common units and restricted stock units, units (Note 9)								(33,534)	(22,312)
Repurchase of common units and restricted stock units (Note 9)	(1,199)	(603)	(1,199)	(603)				(1,199)	(603)
Settlement of restricted stock units, units (Note 9)								2,579
Settlement of restricted stock units (Note 9)	(10)		(10)					(10)
Exercise of stock options, units									5,000
Exercise of stock options		129		129					129
Preferred distributions	(3,313)	(4,418)	(3,313)	(4,418)				(3,313)	(4,418)
Distributions declared per common unit ($0.35 per unit)	(27,412)	(24,892)	(27,412)	(24,892)				(27,412)	(24,892)
Ending Balance	$ 2,232,540	$ 1,729,850	$ 2,229,192	$ 1,727,156	$ 96,155	$ 192,411	$ 192,411	$ 2,036,781	$ 1,631,001	$ 3,348	$ 2,694
Ending Balance units								77,176,208	70,067,974