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, 2014	Sep. 30, 2013	Sep. 30, 2014 Total Partners Capital [Member]	Sep. 30, 2013 Total Partners Capital [Member]	Sep. 30, 2014 Noncontrolling Interest [Member]	Sep. 30, 2013 Noncontrolling Interest [Member]	Sep. 30, 2014 Partners Capital Preferred Units [Member]	Dec. 31, 2013 Partners Capital Preferred Units [Member]	Sep. 30, 2013 Partners Capital Preferred Units [Member]	Dec. 31, 2012 Partners Capital Preferred Units [Member]	Sep. 30, 2014 Partners Capital Common Unit [Member]	Sep. 30, 2013 Partners Capital Common Unit [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ 2,516,160	$ 2,235,933	$ 2,507,772	$ 2,232,654	$ 8,388	$ 3,279	$ 192,411	$ 192,411	$ 192,411	$ 192,411	$ 2,315,361	$ 2,040,243
Beginning Balance units											83,959,144	76,753,484
Net income	152,378	21,518	152,177	21,340	201	178					152,177	21,340
Issuance of common units, units											370,700	7,210,838
Issuance of common units	22,136	349,951	22,136	349,951							22,136	349,951
Issuance of share-based compensation awards, units												0
Issuance of share-based compensation awards	1,281	1,075	1,281	1,075							1,281	1,075
Noncash amortization of share-based compensation	10,345	7,096	10,345	7,096							10,345	7,096
Repurchase of common units and restricted stock units, units											(48,017)	(34,164)
Repurchase of common units and restricted stock units	(2,861)	(1,803)	(2,861)	(1,803)							(2,861)	(1,803)
Settlement of restricted stock units, units											108,529	4,363
Settlement of restricted stock units for shares of common stock	0	(10)	0	(10)							0	(10)
Common units issued in connection with early exchange of 4.25% Exchangeable Senior Notes (Note 5), units											431,270
Common units issued in connection with early exchange of 4.25% Exchangeable Senior Notes (Note 5)	223		223								223
Common units received in connection with capped call option transactions (Note 5), units											(111,206)
Common units received in connection with capped call option transactions (Note 5)	0		0
Exercise of stock options, net, units											482,000	473
Exercise of stock options, net	20,537	128	20,537	128							20,537	128
Contribution by noncontrolling interest in consolidated subsidiary	336	4,885			336	4,885
Preferred distributions	(9,938)	(9,938)	(9,938)	(9,938)							(9,938)	(9,938)
Distributions declared per common unit ($1.05 per unit)	(90,228)	(84,741)	(90,228)	(84,741)							(90,228)	(84,741)
Ending Balance	$ 2,620,369	$ 2,524,094	$ 2,611,444	$ 2,515,752	$ 8,925	$ 8,342	$ 192,411	$ 192,411	$ 192,411	$ 192,411	$ 2,419,033	$ 2,323,341
Ending Balance units											85,192,420	83,934,994