v3.3.1.900

Secured and Unsecured Debt of the Operating Partnership - Exchangeable Senior Notes (Details) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	Nov. 30, 2014	Nov. 30, 2009	Dec. 31, 2015 shares	Dec. 31, 2014 $ / shares shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) $ / shares shares		Dec. 31, 2013 USD ($) $ / shares	Jun. 30, 2015 USD ($)	Nov. 13, 2014 USD ($)
Debt Instrument [Line Items]
Average Trading Price Of The Companys Stock | $ / shares						$ 60.04	[1]	$ 52.12
Debt Instrument, Unamortized Premium									$ 6,200
Capped call transactions
Debt Instrument, Convertible, Conversion Ratio						27.8307
Conversion of Stock, Shares Converted | shares						4,800,796
Interest expense					$ 57,682	$ 67,571		$ 75,870
Exchangeable Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Issuance Date		Nov. 01, 2009
Balance and significant terms of the Exchangeable Notes outstanding
Maturity date	Nov. 01, 2014
Stated interest rate				4.00%		4.00%
Effective interest rate				7.00%		7.00%
Capped call transactions
Debt Instrument, Convertible, Conversion Price | $ / shares				$ 35.93		$ 35.93
Kilroy Realty, L.P. [Member]
Debt Instrument [Line Items]
Interest Costs Incurred					109,647	$ 114,661		111,238
Interest Costs Capitalized Adjustment					(51,965)	(47,090)		(35,368)
Capped call transactions
Interest expense					$ 57,682	$ 67,571		$ 75,870
Kilroy Realty, L.P. [Member] | Exchangeable Notes [Member]
Balance and significant terms of the Exchangeable Notes outstanding
Long-term Debt, Gross										$ 135,500
Common Stock
Debt Disclosure [Abstract]
Stock issued during period, shares, conversion of convertible securities, net of adjustments | shares					1,255,917
Debt Instrument [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities | shares			1,660,053	431,270
Common Stock, Issued, Net of Capped Calls | shares				320,064	1,575,981
[1] Period Ended November 15, 2014(1) Year Ended December 31, 2013Per share average trading price of the Company's common stock$60.04 $52.12_______________(1) Represents the maturity date of the 4.25% Exchangeable Notes.

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