Consolidated Balance Sheets (KILROY REALTY, L.P.) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entity Consolidated Carrying Amounts, Real Estate Assets, net	$ 187,254	$ 211,755
Noncontrolling common units of the Operating Partnership	2,381,543	1,764,775
Kilroy Realty, L.P. [Member] | Capital units [Member]
General Partners' Capital Account, Units Issued	93,219,439	92,258,690
General Partners' Capital Account, Units Outstanding	93,219,439	92,258,690
Limited Partners' Capital Account, Units Issued	2,381,543	1,764,775
Noncontrolling common units of the Operating Partnership	2,381,543	1,764,775
Kilroy Realty, L.P. [Member] | Series G Cumulative Redeemable Preferred Unit [Member]
Preferred units, issued	4,000,000	4,000,000
Preferred units outstanding	4,000,000	4,000,000
Preferred stock dividend rate (percentage)	6.875%	6.875%
Preferred stock liquidation preference	$ 100,000	$ 100,000
Kilroy Realty, L.P. [Member] | Series H Cumulative Redeemable Preferred Unit [Member]
Preferred units, issued	4,000,000	4,000,000
Preferred units outstanding	4,000,000	4,000,000
Preferred stock dividend rate (percentage)	6.375%	6.375%
Preferred stock liquidation preference	$ 100,000	$ 100,000