Consolidated Balance Sheets (KILROY REALTY, L.P.) (Parenthetical) (Kilroy Realty, L.P. [Member], USD $) In Thousands, except Share data, unless otherwise specified			9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2011 Series E Cumulative Redeemable Preferred Stock	Dec. 31, 2010 Series E Cumulative Redeemable Preferred Stock	Sep. 30, 2011 Series F Cumulative Redeemable Preferred Stock	Dec. 31, 2010 Series F Cumulative Redeemable Preferred Stock
Partners' Capital (Note 8):
General partner, units issued	58,464,412	52,349,670
General partners, units outstanding	58,464,412	52,349,670
Limited partners, units issued	1,718,131	1,723,131
Limited partnership units outstanding	1,718,131	1,723,131
Preferred stock, shares issued			1,610,000	1,610,000	3,450,000	3,450,000
Preferred stock, shares outstanding			1,610,000	1,610,000	3,450,000	3,450,000
Preferred stock dividend rate percentage			7.80%	7.80%	7.50%	7.50%
Preferred Stock Liquidation preference			$ 40,250	$ 40,250	$ 86,250	$ 86,250