Consolidated Balance Sheets (KILROY REALTY, L.P.) (Parenthetical) (Kilroy Realty, L.P. [Member], USD $)			9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2013 Common Units [Member]	Dec. 31, 2012 Common Units [Member]	Sep. 30, 2013 Series G Cumulative Redeemable Preferred Unit [Member]	Dec. 31, 2012 Series G Cumulative Redeemable Preferred Unit [Member]	Sep. 30, 2013 Series H Cumulative Redeemable Preferred Unit [Member]	Dec. 31, 2012 Series H Cumulative Redeemable Preferred Unit [Member]
Preferred Units, Issued			4,000,000	4,000,000	4,000,000	4,000,000
Preferred Units, Outstanding			4,000,000	4,000,000	4,000,000	4,000,000
Preferred stock dividend rate percentage			6.875%	6.875%	6.375%	6.375%
Preferred Stock Liquidation preference			$ 100,000,000	$ 100,000,000	$ 100,000,000	$ 100,000,000
General partner, units issued	82,113,491	74,926,981
General partners, units outstanding	82,113,491	74,926,981
Limited partners, units issued	1,821,503	1,826,503
Common units held by limited partners	1,821,503	1,826,503