Net 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, 2015		Mar. 31, 2014
Numerator:
Income from continuing operations	$ 44,002		$ 10,874
(Income) Loss from continuing operations attributable to noncontrolling common units of the Operating Partnership	(815)		(160)
Preferred dividends	(3,313)		(3,313)
Allocation to participating securities	(415)	[1]	(427)	[1]
Numerator for basic and diluted income from continuing operations available to common stockholders	39,459		6,974
Income from discontinued operations	0	[2]	91,058	[2]
Income from discontinued operations attributable to noncontrolling common units of the Operating Partnership	0	[2]	(1,927)	[2]
Numerator for basic and diluted net income available to common stockholders	39,459		96,105
Denominator:
Weighted average common shares outstanding – basic (Note 13)	86,896,776		82,124,538
Effect of dilutive securities	537,590		2,015,532
Weighted average common shares outstanding-diluted	87,434,366		84,140,070
Basic earnings per share:
Income (loss) from continuing operations available to common stockholders per common share – basic (Note 14)	$ 0.45		$ 0.08
Income from discontinued operations per common share	$ 0.00	[2]	$ 1.09	[2]
Net income available to common stockholders per share-basic	$ 0.45		$ 1.17
Diluted earnings per share:
Income from continuing operations available to common stockholders per common share – diluted (Note 13)	$ 0.45		$ 0.08
Income from discontinued operations per common share	$ 0.00	[2]	$ 1.06	[2]
Net income available to common stockholders per share-diluted	$ 0.45		$ 1.14
Kilroy Realty, L.P. [Member]
Numerator:
Income from continuing operations	44,002		10,874
Preferred dividends	(3,313)		(3,313)
Allocation to participating securities	(415)	[1]	(427)	[1]
Numerator for basic and diluted income from continuing operations available to common stockholders	40,199		7,069
Income from discontinued operations	0	[2]	91,058	[2]
Numerator for basic and diluted net income available to common stockholders	$ 40,199		$ 98,127
Denominator:
Weighted average common shares outstanding – basic (Note 13)	88,693,306		83,928,993
Effect of dilutive securities	537,590		2,015,532
Weighted average common shares outstanding-diluted	89,230,896		85,944,525
Basic earnings per share:
Income (loss) from continuing operations available to common stockholders per common share – basic (Note 14)	$ 0.45		$ 0.08
Income from discontinued operations per common share	$ 0.00	[2]	$ 1.09	[2]
Net income available to common stockholders per share-basic	$ 0.45		$ 1.17
Diluted earnings per share:
Income from continuing operations available to common stockholders per common share – diluted (Note 13)	$ 0.45		$ 0.08
Income from discontinued operations per common share	$ 0.00	[2]	$ 1.06	[2]
Net income available to common stockholders per share-diluted	$ 0.45		$ 1.14

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

[2] The Company adopted ASU 2014-08 effective January 1, 2015 (see Note 1). As a result, properties classified as held for sale and/or disposed of subsequent to January 1, 2015 that do not represent a strategic shift are no longer presented as discontinued operations.