Net (Loss) Income Available to Common Stockholders Per Share of the Company (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Numerator:
Income from continuing operations	$ 11,440		$ 186
(Income) loss from continuing operations attributable to noncontrolling common units of the Operating Partnership	(172)		72
Preferred distributions	(3,313)		(3,313)
Allocation to participating securities	(427)	[1]	(418)	[1]
Numerator for basic and diluted income (loss) from continuing operations available to common stockholders	7,528		(3,473)
Income from discontinued operations	90,492		2,202
Income from discontinued operations attributable to noncontrolling common units of the Operating Partnership	(1,915)		(50)
Numerator for basic and diluted net income (loss) available to common stockholders	96,105		(1,321)
Denominator:
Weighted average common shares outstanding – basic (Note 14)	82,124,538		74,977,240
Effect of dilutive securities	2,015,532		0
Weighted average common shares outstanding-diluted	84,140,070		74,977,240
Basic earnings per share:
Income (loss) from continuing operations available to common stockholders per common share – basic (Note 14)	$ 0.09		$ (0.05)
Income from discontinued operations per common share	$ 1.08		$ 0.03
Net income (loss) available to common stockholders per share-basic	$ 1.17		$ (0.02)
Diluted earnings per share:
Income (loss) from continuing operations available to common stockholders per common share – diluted (Note 14)	$ 0.09		$ (0.05)
Income from discontinued operations per common share	$ 1.05		$ 0.03
Net income (loss) available to common stockholders per share-diluted	$ 1.14		$ (0.02)
Stock options outstanding	1,520,500
Kilroy Realty, L.P. [Member]
Numerator:
Income from continuing operations	11,440		186
Preferred distributions	(3,313)		(3,313)
Allocation to participating securities	(427)	[1]	(418)	[1]
Numerator for basic and diluted income (loss) from continuing operations available to common stockholders	7,635		(3,614)
Income from discontinued operations	90,492		2,202
Numerator for basic and diluted net income (loss) available to common stockholders	$ 98,127		$ (1,412)
Denominator:
Weighted average common shares outstanding – basic (Note 14)	83,928,993		76,803,743
Effect of dilutive securities	2,015,532		0
Weighted average common shares outstanding-diluted	85,944,525		76,803,743
Basic earnings per share:
Income (loss) from continuing operations available to common stockholders per common share – basic (Note 14)	$ 0.09		$ (0.05)
Income from discontinued operations per common share	$ 1.08		$ 0.03
Net income (loss) available to common stockholders per share-basic	$ 1.17		$ (0.02)
Diluted earnings per share:
Income (loss) from continuing operations available to common stockholders per common share – diluted (Note 14)	$ 0.09		$ (0.05)
Income from discontinued operations per common share	$ 1.05		$ 0.03
Net income (loss) available to common stockholders per share-diluted	$ 1.14		$ (0.02)

[1] Participating securities include nonvested shares, certain time-based RSUs and vested market-measure RSUs.