Consolidated Statements of Capital (KILROY REALTY, L.P.) (Kilroy Realty, L.P. [Member], USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended							9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Total Partners Capital [Member]	Sep. 30, 2012 Total Partners Capital [Member]	Sep. 30, 2012 Partners Capital Preferred Units [Member]	Sep. 30, 2013 Partners Capital Preferred Units [Member]	Dec. 31, 2012 Partners Capital Preferred Units [Member]	Sep. 30, 2013 Partners Capital Common Unit [Member]	Sep. 30, 2012 Partners Capital Common Unit [Member]	Sep. 30, 2013 Noncontrolling Interest In Consolidated Subsidiaries [Member]	Sep. 30, 2012 Noncontrolling Interest In Consolidated Subsidiaries [Member]	Sep. 30, 2012 Series A Preferred Units [Member]	Sep. 30, 2012 Series A Preferred Units [Member] Total Partners Capital [Member]	Sep. 30, 2012 Series A Preferred Units [Member] Partners Capital Common Unit [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	21,518	83,471	21,340	83,327				21,340	83,327	178	144
Issuance of Series G and Series H Preferred stock		192,411		192,411	192,411
Redemption of Series E and Series F Preferred stock, shares					(121,582)
Redemption of Preferred units		(126,500)		(126,500)					(4,918)
Original issuance costs of redeemed preferred units	0	(6,980)										(2,062)	(2,062)	(2,062)
Issuance of common units								7,210,838	15,813,189
Issuance of common units	349,951	662,371	349,951	662,371				349,951	662,371
Issuance of common units in connection with an operating property acquisition, shares									118,372
Issuance of common units	4,885	5,604		5,604					5,604	4,885
Issuance of share-based compensation awards, units								0	62,137
Issuance of share-based compensation awards	1,075	957	1,075	957				1,075	957
Noncash amortization of share-based compensation	7,096	6,182	7,096	6,182				7,096	6,182
Repurchase of common units and restricted stock units, units								(34,164)	(22,312)
Repurchase of common units and restricted stock units	(1,803)	(603)	(1,803)	(603)				(1,803)	(603)
Settlement of restricted stock units, units								4,363	5,208
Settlement of restricted stock units	(10)	(133)	(10)	(133)				(10)	(133)
Exercise of stock options, net, units								473	5,000
Exercise of stock options, net	128	129	128	129				128	129
Preferred distributions	(9,938)	(10,795)	(9,938)	(10,795)				(9,938)	(10,795)
Distributions declared per common unit ($1.05 per unit)	(84,741)	(77,146)	(84,741)	(77,146)				(84,741)	(77,146)
Ending Balance	$ 2,524,094	$ 2,061,368	$ 2,515,752	$ 2,058,583	$ 192,411	$ 192,411	$ 192,411	$ 2,323,341	$ 1,866,172	$ 8,342	$ 2,785
Ending Balance units								83,934,994	76,519,442