Secured and Unsecured Debt of the Operating Partnership (Tables)

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Interest Expense For Exchangeable Notes [Table Text Block]

The following table summarizes the total interest expense attributable to the 4.25% Exchangeable Notes prior to maturity in November 2014, based on the effective interest rates, before the effect of capitalized interest, for the years ended December 31, 2014 and 2013:



	Year Ended December 31,
	2014		2013

Contractual interest payments	$	5,608	$	7,331
Amortization of discount	3,769		4,427
Interest expense attributable to the 4.25% Exchangeable Notes	$	9,377	$	11,758

Per Share Average Trading Price Of Companys Common Stock On Stock Exchange [Tables Text Block]

For the respective reporting periods noted below, which preceding maturity of the 4.25% Exchangeable Notes on November 15, 2014, the per share average trading price of the Company's common stock on the NYSE was higher than the $35.93 exchange price for the 4.25% Exchangeable Notes, as presented in the table below. See Note 20 “Net Income Available to Common Stockholders Per Share of the Company” and Note 21 “Net Income Available to Common Unitholders Per Unit of the Operating Partnership” for a discussion of the impact of the 4.25% Exchangeable Notes on our diluted earnings per share and unit calculations for the years ended December 31, 2014 and 2013.



	Period Ended November 15, 2014⁽¹⁾		Year Ended December 31, 2013
Per 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.

Debt Instrument Redemption [Table Text Block]

The table below summarizes the significant terms of the Company’s $172.5 million 4.25% Exchangeable Notes due November 2014 (the “4.25% Exchangeable Notes”) prior to their repayment upon maturity in November 2014.



4.25% Exchangeable Notes		December 31, 2014
Issuance date		November 2009
Maturity date		November 2014
Stated coupon rate ⁽¹⁾		4.25%
Effective interest rate ⁽²⁾		7.13%
Exchange rate per $1,000 principal value of the 4.25% Exchangeable Notes, as adjusted ⁽³⁾		27.8307
Exchange price as adjusted ⁽³⁾		$35.93
Number of shares on which the aggregate consideration to be delivered on conversion ⁽³⁾		4,800,796

_______________


(1)	Interest on the 4.25% Exchangeable Notes was payable semi-annually in arrears on May 15th and November 15th of each year.


(2)	Represents the rate at which we record interest expense for financial reporting purposes, which reflects the amortization of the discounts on the 4.25% Exchangeable Notes. This rate represents our conventional debt borrowing rate at the date of issuance.


(3)	The exchange rate, exchange price, and the number of shares to be delivered upon conversation were subject to adjustment under certain circumstances, including increases in our common dividends as of December 31, 2014.

Kilroy Realty, L.P. [Member]

Debt Instrument [Line Items]

Schedule of Line of Credit Facilities [Table Text Block]

The following table summarizes the balance and terms of our unsecured revolving credit facility as of December 31, 2015 and December 31, 2014:



	December 31, 2015			December 31, 2014
	(in thousands)
Outstanding borrowings	$	—		$	140,000
Remaining borrowing capacity	600,000			460,000
Total borrowing capacity ⁽¹⁾	$	600,000		$	600,000
Interest rate ⁽²⁾	—		%	1.41		%
Facility fee-annual rate ⁽³⁾	0.200%			0.250%
Maturity date	July 2019

_______________


(1)	We may elect to borrow, subject to bank approval and obtaining commitments for any additional borrowing capacity, up to an additional $311.0 million under an accordion feature under the terms of the unsecured revolving credit facility and unsecured term loan facility.


(2)	Our unsecured revolving credit facility interest rate was calculated based on an annual rate of LIBOR plus1.050% and LIBOR plus 1.250% as of December 31, 2015 and December 31, 2014, respectively.


(3)	Our facility fee is paid on a quarterly basis and is calculated based on the total borrowing capacity. In addition to the facility fee, we incurred debt origination and legal costs. As of December 31, 2015, $4.6 million of deferred financing costs remains to be amortized through the amended maturity date of our unsecured revolving credit facility.

Schedule of Term Loan Facilities [Table Text Block]

The following table summarizes the balance and terms of our term loan facility, which is included in our unsecured debt, as of December 31, 2015 and December 31, 2014:



	December 31, 2015			December 31, 2014
	(in thousands)
Outstanding borrowings	$	150,000		$	150,000
Interest rate ⁽¹⁾	1.40		%	1.56		%
Maturity date	July 2019			July 2019

_______________


(1)	Our unsecured term loan facility interest rate was calculated based on an annual rate of LIBOR plus 1.150% and LIBOR plus 1.400% as of December 31, 2015 and December 31, 2014, respectively.

Stated debt maturities and scheduled amortization payments, excluding debt discounts

The following table summarizes the stated debt maturities and scheduled amortization payments as of December 31, 2015:



Year	(in thousands)
2016	$	9,734
2017	71,734
2018	451,713
2019	265,355
2020	251,962
Thereafter	1,189,198
Total aggregate principal value	$	2,239,696
Less net unamortized discounts	(1,188		)
Total debt, net of unamortized discounts	$	2,238,508

Capitalized interest and loan fees

The following table sets forth gross interest expense reported in continuing operations, including debt discount/premium and loan cost amortization, net of capitalized interest, for the years ended December 31, 2015, 2014 and 2013. The interest expense capitalized was recorded as a cost of development and redevelopment, and increased the carrying value of undeveloped land and construction in progress.



	Year Ended December 31,
	2015			2014			2013
	(in thousands)
Gross interest expense	$	109,647		$	114,661		$	111,238
Capitalized interest	(51,965		)	(47,090		)	(35,368		)
Interest expense	$	57,682		$	67,571		$	75,870

Kilroy Realty, L.P. [Member] | Secured Debt [Member]

Debt Instrument [Line Items]

Debt balance and significant terms

The following table sets forth the composition of our secured debt as of December 31, 2015 and 2014:



	Annual Stated Interest Rate ⁽¹⁾	GAAP Effective Rate ⁽¹⁾⁽²⁾	Maturity Date	December 31,
Type of Debt	Annual Stated Interest Rate ⁽¹⁾	GAAP Effective Rate ⁽¹⁾⁽²⁾	Maturity Date	2015 ⁽³⁾		2014 ⁽³⁾
				(in thousands)
Mortgage note payable ⁽⁵⁾	4.27%	4.27%	February 2018	$	128,315	$	130,767
Mortgage note payable ⁽⁵⁾	4.48%	4.48%	July 2027	96,354		97,000
Mortgage note payable ⁽⁴⁾⁽⁵⁾	6.05%	3.50%	June 2019	85,890		89,242
Mortgage note payable	6.51%	6.51%	February 2017	65,563		66,647
Mortgage note payable	7.15%	7.15%	May 2017	3,987		6,568
Mortgage note payable⁽⁵⁾⁽⁶⁾	5.23%	3.50%	January 2016	—		52,793
Mortgage note payable ⁽⁵⁾⁽⁶⁾	5.57%	3.25%	February 2016	—		40,258
Mortgage note payable ⁽⁵⁾	5.09%	3.50%	August 2015	—		34,311
Mortgage note payable	4.94%	4.00%	April 2015	—		26,285
Other ⁽⁷⁾	Various	Various	Various	1,809		2,421
Total				$	381,918	$	546,292

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(1)	All interest rates presented are fixed-rate interest rates.


(2)	This represents the rate at which interest expense is recorded for financial reporting purposes, which reflects the amortization of discounts/premiums, excluding debt issuance costs.


(3)	Amounts reported include the amounts of unamortized debt premiums of $6.2 million and $10.3 million as of December 31, 2015 and 2014, respectively.


(4)	In January 2013, in connection with the acquisition of two office buildings in Seattle, Washington, we assumed a mortgage loan that is secured by the project. The loan requires monthly principal and interest payments based on a 6.4 year amortization period. As of December 31, 2015 and 2014, the mortgage loan had unamortized debt premiums of $6.2 million and $8.0 million, respectively.


(5)	The secured debt and the related properties that secure the debt are held in a special purpose entity and the properties are not available to satisfy the debts and other obligations of the Company or the Operating Partnership.


(6)	These mortgage notes payable were repaid during the year ended December 31, 2015 at par.


(7)	Excludes $0.6 million of secured debt related to real estate assets held for sale as of December 31, 2015.

Kilroy Realty, L.P. [Member] | Exchangeable Notes [Member]

Debt Instrument [Line Items]

Debt balance and significant terms

Uns

Kilroy Realty, L.P. [Member] | Unsecured Senior Notes [Member]

Debt Instrument [Line Items]

Debt balance and significant terms

The following table summarizes the balance and significant terms of the registered unsecured senior notes issued by the Operating Partnership as of December 31, 2015 and 2014:



					Principal Amount as of December 31,
	Issuance date	Maturity date	Stated coupon rate	Effective interest rate⁽¹⁾	2015			2014
					(in thousands)
4.375% Unsecured Senior Notes ⁽²⁾	September 2015	October 2025	4.375%	4.440%	$	400,000		$	—
Unamortized discount					(2,159		)	$	—
Net carrying amount					$	397,841		$	—

4.250% Unsecured Senior Notes ⁽³⁾	July 2014	August 2029	4.250%	4.350%	$	400,000		$	400,000
Unamortized discount					(4,050		)	(4,348		)
Net carrying amount					$	395,950		$	395,652

3.800% Unsecured Senior Notes ⁽⁴⁾	January 2013	January 2023	3.800%	3.804%	$	300,000		$	300,000
Unamortized discount					(70		)	(79		)
Net carrying amount					$	299,930		$	299,921

4.800% Unsecured Senior Notes ⁽⁴⁾⁽⁵⁾	July 2011	July 2018	4.800%	4.827%	$	325,000		$	325,000
Unamortized discount					(191		)	(265		)
Net carrying amount					$	324,809		$	324,735

6.625% Unsecured Senior Notes ⁽⁶⁾	May 2010	June 2020	6.625%	6.743%	$	250,000		$	250,000
Unamortized discount					(940		)	(1,154		)
Net carrying amount					$	249,060		$	248,846

5.000% Unsecured Senior Notes ⁽⁷⁾	November 2010	November 2015	5.000%	5.014%	$	—		$	325,000
Unamortized discount					—			(33		)
Net carrying amount					$	—		$	324,967

Total Unsecured Senior Notes, Net					$	1,667,590		$	1,594,121

________________________


(1)	This represents the rate at which interest expense is recorded for financial reporting purposes, which reflects the amortization of initial issuance discounts, excluding debt issuance costs.


(2)	Interest on these notes is payable semi-annually in arrears on April 1st and October 1st of each year.


(3)	Interest on these notes is payable semi-annually in arrears on February 15th and August 15th of each year.


(4)	Interest on these notes is payable semi-annually in arrears on January 15th and July 15th of each year.

(5)

In October 2015, certain common limited partners in the Operating Partnership that previously contributed their interests in the property at 6255 W. Sunset Blvd., Los Angeles, California to the Operating Partnership entered into an agreement with the Company. Pursuant to this agreement, such common limited partners will reimburse the Company for a portion of any amounts the Company may be required to pay pursuant to its guarantee of the Operating Partnership's 4.800% Senior Notes due 2018 or that the Company may otherwise become required to pay under applicable law with respect to such notes.


(6)	Interest on these notes is payable semi-annually in arrears on June 1st and December 1st of each year.


(7)	Interest of these notes is payable semi-annually in arrears on May 3rd and November 3rd of each year.