Kilroy Realty (KRC) 10-Q 30 Oct 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 24, 2014
Entity Registrant Name	'KILROY REALTY CORP	'
Entity Central Index Key	'0001025996	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Document Type	'10-Q	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	'	83,956,738
Kilroy Realty, L.P. [Member]	'	'
Entity Registrant Name	'Kilroy Realty, L.P.	'
Entity Central Index Key	'0001493976	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Non-accelerated Filer	'
Document Type	'10-Q	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Amendment Flag	'false	'

Consolidated_Balance_Sheets_Un

Consolidated Balance Sheets (Unaudited) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
REAL ESTATE ASSETS:	'		'
Land and improvements (Note 2)	$757,036		$657,491
Buildings and improvements (Note 2)	3,882,015		3,590,699
Undeveloped land and construction in progress (Note 2)	1,112,046		1,016,757
Total real estate assets held for investment	5,751,097		5,264,947
Accumulated depreciation and amortization	-912,623		-818,957
Total real estate assets held for investment, net ($98,121 and $234,532 of VIE, respectively, Note 1)	4,838,474		4,445,990
REAL ESTATE ASSETS AND OTHER ASSETS HELD FOR SALE, NET (Note 13)	49,815		213,100
CASH AND CASH EQUIVALENTS	200,431		35,377
RESTRICTED CASH (Notes 1 and 13)	17,487		49,780
MARKETABLE SECURITIES (Note 11)	12,076		10,008
CURRENT RECEIVABLES, NET (Note 4)	6,443	[1]	10,743
DEFERRED RENT RECEIVABLES, NET (Note 4)	139,910	[2]	127,123
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET (Notes 2 and 3)	183,057		186,622
DEFERRED FINANCING COSTS, NET	19,373		16,502
PREPAID EXPENSES AND OTHER ASSETS, NET	20,398		15,783
TOTAL ASSETS	5,487,464		5,111,028
LIABILITIES:	'		'
Secured debt (Notes 5 and 11)	549,896	[3]	560,434	[3]
Exchangeable senior notes, net (Notes 5 and 11)	135,049		168,372
Unsecured debt, net (Notes 5 and 11)	1,743,962		1,431,132
Unsecured line of credit (Notes 5 and 11)	0		45,000
Accounts payable, accrued expenses and other liabilities	243,602		198,467
Accrued distributions (Note 16)	31,897		31,490
Deferred revenue and acquisition-related intangible liabilities, net (Notes 2 and 3)	114,504		101,286
Rents received in advance and tenant security deposits	45,086		44,240
Liabilities of real estate assets held for sale (Note 13)	3,099		14,447
Total liabilities	2,867,095		2,594,868
COMMITMENTS AND CONTINGENCIES (Note 10)	'		'
Preferred stock, $.01 par value, 30,000,000 shares authorized:	'		'
Common stock, $.01 par value, 150,000,000 shares authorized, 83,388,220 and 82,153,944 shares issued and outstanding, respectively	834		822
Additional paid-in capital	2,530,282		2,478,975
Distributions in excess of earnings	-159,799		-210,896
Total stockholders’ equity	2,563,728		2,461,312
Noncontrolling interest :	'		'
Common units of the Operating Partnership (Note 6)	51,419		49,963
Noncontrolling interest in consolidated subsidiary (Notes 1 and 6)	5,222		4,885
Total noncontrolling interests	56,641		54,848
Total equity	2,620,369		2,516,160
TOTAL LIABILITIES AND EQUITY	5,487,464		5,111,028
Series G Cumulative Redeemable Preferred Stock	'		'
Preferred stock, $.01 par value, 30,000,000 shares authorized:	'		'
Cumulative Redeemable Preferred stock	96,155		96,155
Series H Cumulative Redeemable Preferred Stock	'		'
Preferred stock, $.01 par value, 30,000,000 shares authorized:	'		'
Cumulative Redeemable Preferred stock	$96,256		$96,256
[1]	Excludes current receivables, net related to properties held for sale at September 30, 2014.
[2]	Excludes deferred rent receivables, net related to properties held for sale at September 30, 2014.
[3]	Amounts reported include the amounts of unamortized debt premiums and discounts for the periods presented.

Consolidated_Balance_Sheets_Un1

Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Carrying amounts of consolidated VIE	$98,121,000	$234,532,000
Common stock, par value	$0.01	'
Common Stock [Member]	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	83,388,220	82,153,944
Common stock, shares outstanding	83,388,220	82,153,944
Preferred Stock [Member]	'	'
Preferred stock, par value	$0.01	$0.01
Preferred stock, shares authorized	30,000,000	30,000,000
Series G Cumulative Redeemable Preferred Stock	'	'
Preferred stock, par value	$0.01	$0.01
Preferred stock dividend rate percentage	6.88%	6.88%
Preferred stock, shares authorized	4,600,000	4,600,000
Preferred stock, shares issued	4,000,000	4,000,000
Preferred stock, shares outstanding	4,000,000	4,000,000
Preferred Stock Liquidation preference	100,000,000	100,000,000
Series H Cumulative Redeemable Preferred Stock	'	'
Preferred stock, par value	$0.01	$0.01
Preferred stock dividend rate percentage	6.38%	6.38%
Preferred stock, shares authorized	4,000,000	4,000,000
Preferred stock, shares issued	4,000,000	4,000,000
Preferred stock, shares outstanding	4,000,000	4,000,000
Preferred Stock Liquidation preference	$100,000,000	$100,000,000

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
REVENUES:	'	'	'	'
Rental income	$115,221	$103,354	$338,911	$303,573
Tenant reimbursements	11,346	9,583	33,399	28,350
Other property income (Note 12)	2,457	608	7,650	6,584
Total revenues	129,024	113,545	379,960	338,507
EXPENSES	'	'	'	'
Property expenses	25,801	24,470	75,448	69,895
Real estate taxes	11,008	10,088	32,728	29,129
Provision for bad debts	58	101	58	196
Ground leases	771	929	2,306	2,665
General and administrative expenses	11,138	10,226	33,806	29,750
Acquisition-related expenses	431	568	1,268	1,387
Depreciation and amortization	50,032	45,804	148,647	138,652
Total expenses	99,239	92,186	294,261	271,674
OTHER (EXPENSES) INCOME:	'	'	'	'
Interest income and other net investment gains/(losses) (Note 11)	-9	673	587	1,084
Interest expense (Note 5)	-16,608	-18,853	-49,880	-58,021
Total other (expenses) income	-16,617	-18,180	-49,293	-56,937
INCOME FROM CONTINUING OPERATIONS BEFORE GAIN ON SALE OF LAND	13,168	3,179	36,406	9,896
Gain on sale of land (Note 13)	0	0	3,490	0
INCOME FROM CONTINUING OPERATIONS	13,168	3,179	39,896	9,896
DISCONTINUED OPERATIONS (Note 13)	'	'	'	'
Income from discontinued operations	548	5,848	2,091	11,199
Gains on dispositions of discontinued operations	5,587	0	110,391	423
Total income from discontinued operations	6,135	5,848	112,482	11,622
NET INCOME	19,303	9,027	152,378	21,518
Net income attributable to noncontrolling common units of the Operating Partnership	-321	-131	-3,011	-266
NET INCOME ATTRIBUTABLE TO KILROY REALTY CORPORATION	18,982	8,896	149,367	21,252
PREFERRED DIVIDENDS	-3,313	-3,312	-9,938	-9,938
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS	$15,669	$5,584	$139,429	$11,314
Income (loss) from continuing operations available to common stockholders per common share – basic (Note 14)	$0.11	$0	$0.34	($0.02)
Income (loss) from continuing operations available to common stockholders per common share – diluted (Note 14)	$0.11	$0	$0.33	($0.02)
Net income available to common stockholders per share – basic (Note 14)	$0.18	$0.07	$1.67	$0.13
Net income available to common stockholders per share – diluted (Note 14)	$0.18	$0.07	$1.63	$0.13
Weighted average common shares outstanding – basic (Note 14)	83,161,323	76,768,893	82,525,033	75,750,822
Weighted average common shares outstanding – diluted (Note 14)	85,110,456	76,768,893	84,622,622	75,750,822
Dividends declared per common share	$0.35	$0.35	$1.05	$1.05

Consolidated_Statements_of_Equ

Consolidated Statements of Equity (Unaudited) (USD $)	Total	Common Stock [Member]	Total Stockholders' Equity	Preferred Stock [Member]	Common Stock Additional Paid-in Capital	Common Stock Distributions in Excess of Earnings	Noncontrolling Interest [Member]	Kilroy Realty, L.P. [Member]	Kilroy Realty, L.P. [Member]	Common Stock [Member]	Issuance of Equity under ATM Program [Member]
In Thousands, except Share data, unless otherwise specified	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	Noncontrolling Interest [Member]		Common Stock [Member]
									USD ($)
Beginning Balance at Dec. 31, 2012	$2,235,933	$749	$2,189,630	$192,411	$2,126,005	($129,535)	$46,303	'	'	'	'
Beginning Balance, shares at Dec. 31, 2012	'	74,926,981	'	'	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'	'	'
Net income	21,518	'	21,252	'	'	21,252	266	21,518	178	'	'
Issuance of common stock (Note 7), shares	'	7,215,838	'	'	'	'	'	'	'	'	'
Issuance of common stock (Note 7)	349,951	72	349,951	'	349,879	'	'	'	'	'	'
Issuance of share-based compensation awards, shares	'	0	'	'	'	'	'	'	'	'	'
Issuance of share-based compensation awards	1,075	'	1,075	'	1,075	'	'	'	'	'	'
Noncash amortization of share-based compensation	7,096	'	7,096	'	7,096	'	'	7,096	'	'	'
Repurchase of common stock and restricted stock units, shares	'	-34,164	'	'	'	'	'	'	'	'	'
Repurchase of common stock and restricted stock units	-1,803	'	-1,803	'	-1,803	'	'	'	'	'	'
Settlement of restricted stock units for shares of common stock, shares	'	4,363	'	'	'	'	'	'	'	'	'
Settlement of restricted stock units for shares of common stock	-10	'	-10	'	-10	'	'	-10	'	'	'
Exercise of stock options, net, shares	'	473	'	'	'	'	'	'	'	'	'
Exercise of stock options, net	128	'	128	'	128	'	'	'	'	'	'
Adjustment for noncontrolling interest	0	'	-5,946	'	-5,946	'	5,946	'	'	'	'
Contribution by noncontrolling interest in consolidated subsidiary	4,885	'	'	'	'	'	4,885	4,885	4,885	'	'
Preferred dividends	-9,938	'	-9,938	'	'	-9,938	'	-9,938	'	'	'
Dividends declared per common share and common unit ($1.05 per share/unit)	-84,741	'	-82,827	'	'	-82,827	-1,914	'	'	'	'
Ending Balance at Sep. 30, 2013	2,524,094	821	2,468,608	192,411	2,476,424	-201,048	55,486	'	'	'	'
Ending Balance, shares at Sep. 30, 2013	'	82,113,491	'	'	'	'	'	'	'	'	'
Beginning Balance at Jun. 30, 2013	'	'	'	'	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'	'	'
Net income	9,027	'	'	'	'	'	'	9,027	'	'	'
Ending Balance at Sep. 30, 2013	2,524,094	'	'	192,411	'	'	'	'	'	'	'
Beginning Balance at Dec. 31, 2013	2,516,160	822	2,461,312	192,411	2,478,975	-210,896	54,848	'	'	'	'
Beginning Balance, shares at Dec. 31, 2013	'	82,153,944	'	'	'	'	'	'	'	82,153,944	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'	'	'
Net income	152,378	'	149,367	'	'	149,367	3,011	152,378	201	'	'
Issuance of common stock (Note 7), shares	'	370,700	'	'	'	'	'	'	'	'	370,700
Issuance of common stock (Note 7)	22,136	4	22,136	'	22,132	'	'	'	'	'	'
Issuance of share-based compensation awards, shares	'	0	'	'	'	'	'	'	'	'	'
Issuance of share-based compensation awards	1,281	'	1,281	'	1,281	'	'	'	'	'	'
Noncash amortization of share-based compensation	10,345	'	10,345	'	10,345	'	'	10,345	'	'	'
Repurchase of common stock and restricted stock units, shares	'	-48,017	'	'	'	'	'	'	'	'	'
Repurchase of common stock and restricted stock units	-2,861	'	-2,861	'	-2,861	'	'	'	'	'	'
Settlement of restricted stock units for shares of common stock, shares	'	108,529	'	'	'	'	'	'	'	'	'
Settlement of restricted stock units for shares of common stock	0	'	0	'	0	'	'	0	'	'	'
Common shares issued in connection with early exchange of 4.25% Exchangeable Senior Notes (Note 5), shares	'	431,270	'	'	'	'	'	'	'	'	'
Common shares issued in connection with early exchange of 4.25% Exchangeable Senior Notes, net of equity component (Note 5)	223	4	223	'	219	'	'	223	'	'	'
Common shares received in connection with capped call option transactions (Note 5), shares	'	-111,206	'	'	'	'	'	'	'	'	'
Common shares received in connection with capped call option transactions (Note 5)	0	'	0	'	'	'	'	0	'	'	'
Exercise of stock options, net, shares	'	482,000	'	'	'	'	'	'	'	'	'
Exercise of stock options, net	20,537	4	20,537	'	20,533	'	'	'	'	'	'
Exchange of common units of the Operating Parternship, shares	'	1,000	'	'	'	'	'	'	'	'	'
Exchange of common units of the Operating Partnership	0	'	28	'	28	'	-28	'	'	'	'
Adjustment for noncontrolling interest	0	'	-370	'	-370	'	370	'	'	'	'
Contribution by noncontrolling interest in consolidated subsidiary	336	'	'	'	'	'	336	336	336	'	'
Preferred dividends	-9,938	'	-9,938	'	'	-9,938	'	-9,938	'	'	'
Dividends declared per common share and common unit ($1.05 per share/unit)	-90,228	'	-88,332	'	'	-88,332	-1,896	'	'	'	'
Ending Balance at Sep. 30, 2014	2,620,369	834	2,563,728	192,411	2,530,282	-159,799	56,641	'	'	'	'
Ending Balance, shares at Sep. 30, 2014	'	83,388,220	'	'	'	'	'	'	'	83,388,220	'
Beginning Balance at Jun. 30, 2014	'	'	'	'	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'	'	'
Net income	19,303	'	'	'	'	'	'	19,303	'	'	'
Ending Balance at Sep. 30, 2014	$2,620,369	'	'	$192,411	'	'	'	'	'	'	'
Ending Balance, shares at Sep. 30, 2014	'	'	'	'	'	'	'	'	'	83,388,220	'

Consolidated_Statements_of_Equ1

Consolidated Statements of Equity (Unaudited) (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Stockholders' Equity [Abstract]	'	'	'	'
Dividends declared per common share	$0.35	$0.35	$1.05	$1.05

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:	'	'
Net income	$152,378	$21,518
Adjustments to reconcile net income to net cash provided by operating activities (including discontinued operations):	'	'
Depreciation and amortization of building and improvements and leasing costs	148,878	148,982
Increase in provision for bad debts	58	196
Depreciation of furniture, fixtures and equipment	1,731	1,363
Noncash amortization of share-based compensation awards	8,817	6,454
Noncash amortization of deferred financing costs and debt discounts and premiums	3,563	4,047
Noncash amortization of net below market rents (Note 3)	-6,216	-6,015
Gains on dispositions of discontinued operations (Note 13)	-110,391	-423
Gain on sale of land (Note 13)	-3,490	0
Noncash amortization of deferred revenue related to tenant-funded tenant improvements	-7,695	-7,585
Straight-line rents	-15,245	-18,188
Net change in other operating assets	-795	-6,435
Net change in other operating liabilities	25,671	42,844
Insurance proceeds received for property damage	0	-448
Net cash provided by operating activities	197,264	186,310
CASH FLOWS FROM INVESTING ACTIVITIES:	'	'
Expenditures for acquisition of operating properties (Note 2)	-106,125	-202,682
Expenditures for operating properties	-93,977	-83,991
Expenditures for development and redevelopment properties and undeveloped land	-292,803	-222,192
Expenditures for acquisition of development and redevelopment properties (Note 2)	-97,727	-13,269
Net proceeds received from dispositions of operating properties and land (Note 13)	368,381	14,409
Insurance proceeds received from property damage	0	448
Decrease (increase) in acquisition-related deposits	1,000	-4,000
Decrease in restricted cash (Notes 1 and 13)	32,293	229,613
Net cash used in investing activities	-188,958	-281,664
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'
Net proceeds from issuance of common stock (Note 7)	22,136	349,951
Borrowings on unsecured line of credit	365,000	10,000
Repayments on unsecured line of credit	-410,000	-195,000
Principal payments on secured debt	-7,315	-91,298
Proceeds from the issuance of unsecured debt (Note 5)	395,528	299,901
Repayments of unsecured debt (Note 5)	-83,000	0
Repayments for early redemption of exchangeable senior notes (Note 5)	37,092	0
Financing costs	-8,043	-3,975
Repurchase of common stock and restricted stock units	-2,861	-1,813
Proceeds from exercise of stock options (Note 9)	20,537	128
Contributions from noncontrolling interests in consolidated subsidiary	336	0
Dividends and distributions paid to common stockholders and common unitholders	-88,540	-82,152
Dividends and distributions paid to preferred stockholders and preferred unitholders	-9,938	-9,938
Net cash provided by financing activities	156,748	275,804
Net increase in cash and cash equivalents	165,054	180,450
Cash and cash equivalents, beginning of period	35,377	16,700
Cash and cash equivalents, end of period	200,431	197,150
SUPPLEMENTAL CASH FLOWS INFORMATION:	'	'
Cash paid for interest, net of capitalized interest of $33,533 and $23,573 as of September 30, 2014 and 2013, respectively	42,633	47,107
NONCASH INVESTING TRANSACTIONS:	'	'
Accrual for expenditures for operating properties and development and redevelopment properties	92,693	79,866
Tenant improvements funded directly by tenants	23,069	5,750
Assumption of other assets and liabilities in connection with operating and development property acquisitions, net	2,300	422
Contribution of land, net of related liabilities, by noncontrolling interest to consolidated subsidiary	0	4,885
Assumption of secured debt in connection with property acquisitions	0	95,496
NONCASH FINANCING TRANSACTIONS:	'	'
Accrual of dividends and distributions payable to common stockholders and common unitholders	30,258	29,378
Accrual of dividends and distributions payable to preferred stockholders and preferred unitholders	1,656	1,692
Fair value of share-based compensation awards at equity classification date (Note 9)	18,111	10,347
Exchange of common units of the Operating Partnership into shares of the Company’s common stock	$28	$0

Consolidated_Statements_of_Cas1

Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
SUPPLEMENTAL CASH FLOWS INFORMATION:	'	'
Cash paid for interest - capitalized interest amount	$33,533	$23,573

Consolidated_Balance_Sheets_KI

Consolidated Balance Sheets (KILROY REALTY, L.P.) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
REAL ESTATE ASSETS:	'		'
Land and improvements (Note 2)	$757,036		$657,491
Buildings and improvements (Note 2)	3,882,015		3,590,699
Undeveloped land and construction in progress (Note 2)	1,112,046		1,016,757
Total real estate assets held for investment	5,751,097		5,264,947
Accumulated depreciation and amortization	-912,623		-818,957
Total real estate assets held for investment, net ($98,121 and $234,532 of VIE, respectively, Note 1)	4,838,474		4,445,990
REAL ESTATE ASSETS AND OTHER ASSETS HELD FOR SALE, NET (Note 13)	49,815		213,100
CASH AND CASH EQUIVALENTS	200,431		35,377
RESTRICTED CASH (Notes 1 and 13)	17,487		49,780
MARKETABLE SECURITIES (Note 11)	12,076		10,008
CURRENT RECEIVABLES, NET (Note 4)	6,443	[1]	10,743
DEFERRED RENT RECEIVABLES, NET (Note 4)	139,910	[2]	127,123
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET (Notes 2 and 3)	183,057		186,622
DEFERRED FINANCING COSTS, NET	19,373		16,502
PREPAID EXPENSES AND OTHER ASSETS, NET	20,398		15,783
TOTAL ASSETS	5,487,464		5,111,028
LIABILITIES:	'		'
Secured debt (Notes 5 and 11)	549,896	[3]	560,434	[3]
Exchangeable senior notes, net (Notes 5 and 11)	135,049		168,372
Unsecured debt, net (Notes 5 and 11)	1,743,962		1,431,132
Unsecured line of credit (Notes 5 and 11)	0		45,000
Accounts payable, accrued expenses and other liabilities	243,602		198,467
Accrued distributions (Note 16)	31,897		31,490
Deferred revenue and acquisition-related intangible liabilities, net (Notes 2 and 3)	114,504		101,286
Rents received in advance and tenant security deposits	45,086		44,240
Liabilities of real estate assets held for sale (Note 13)	3,099		14,447
Total liabilities	2,867,095		2,594,868
COMMITMENTS AND CONTINGENCIES (Note 10)	'		'
Partners’ Capital (Note 8):	'		'
TOTAL LIABILITIES AND EQUITY	5,487,464		5,111,028
Kilroy Realty, L.P. [Member]	'		'
REAL ESTATE ASSETS:	'		'
Land and improvements (Note 2)	757,036		657,491
Buildings and improvements (Note 2)	3,882,015		3,590,699
Undeveloped land and construction in progress (Note 2)	1,112,046		1,016,757
Total real estate assets held for investment	5,751,097		5,264,947
Accumulated depreciation and amortization	-912,623		-818,957
Total real estate assets held for investment, net ($98,121 and $234,532 of VIE, respectively, Note 1)	4,838,474		4,445,990
REAL ESTATE ASSETS AND OTHER ASSETS HELD FOR SALE, NET (Note 13)	49,815		213,100
CASH AND CASH EQUIVALENTS	200,431		35,377
RESTRICTED CASH (Notes 1 and 13)	17,487		49,780
MARKETABLE SECURITIES (Note 11)	12,076		10,008
CURRENT RECEIVABLES, NET (Note 4)	6,443		10,743
DEFERRED RENT RECEIVABLES, NET (Note 4)	139,910		127,123
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET (Notes 2 and 3)	183,057		186,622
DEFERRED FINANCING COSTS, NET	19,373		16,502
PREPAID EXPENSES AND OTHER ASSETS, NET	20,398		15,783
TOTAL ASSETS	5,487,464		5,111,028
LIABILITIES:	'		'
Secured debt (Notes 5 and 11)	549,896		560,434
Exchangeable senior notes, net (Notes 5 and 11)	135,049		168,372
Unsecured debt, net (Notes 5 and 11)	1,743,962		1,431,132
Unsecured line of credit (Notes 5 and 11)	0		45,000
Accounts payable, accrued expenses and other liabilities	243,602		198,467
Accrued distributions (Note 16)	31,897		31,490
Deferred revenue and acquisition-related intangible liabilities, net (Notes 2 and 3)	114,504		101,286
Rents received in advance and tenant security deposits	45,086		44,240
Liabilities of real estate assets held for sale (Note 13)	3,099		14,447
Total liabilities	2,867,095		2,594,868
Partners’ Capital (Note 8):	'		'
Common units, 83,388,220 and 82,153,944 held by the general partner and 1,804,200 and 1,805,200 held by common limited partners issued and outstanding, respectively	2,419,033		2,315,361
Total partners’ capital	2,611,444		2,507,772
Noncontrolling interests in consolidated subsidiaries (Notes 1 and 6)	8,925		8,388
Total capital	2,620,369		2,516,160
TOTAL LIABILITIES AND EQUITY	5,487,464		5,111,028
Series G Cumulative Redeemable Preferred Unit [Member] | Kilroy Realty, L.P. [Member]	'		'
Partners’ Capital (Note 8):	'		'
Redeemable Preferred stock	96,155		96,155
Series H Cumulative Redeemable Preferred Unit [Member] | Kilroy Realty, L.P. [Member]	'		'
Partners’ Capital (Note 8):	'		'
Redeemable Preferred stock	$96,256		$96,256
[1]	Excludes current receivables, net related to properties held for sale at September 30, 2014.
[2]	Excludes deferred rent receivables, net related to properties held for sale at September 30, 2014.
[3]	Amounts reported include the amounts of unamortized debt premiums and discounts for the periods presented.

Consolidated_Balance_Sheets_KI1

Consolidated Balance Sheets (KILROY REALTY, L.P.) (Parenthetical) (Kilroy Realty, L.P. [Member], USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013
			Common Units [Member]	Common Units [Member]	Series G Cumulative Redeemable Preferred Unit [Member]	Series G Cumulative Redeemable Preferred Unit [Member]	Series H Cumulative Redeemable Preferred Unit [Member]	Series H Cumulative Redeemable Preferred Unit [Member]
Carrying amounts of consolidated VIE	$98,121,000	$234,532,000	'	'	'	'	'	'
Preferred Units, Issued	'	'	'	'	4,000,000	4,000,000	4,000,000	4,000,000
Preferred Units, Outstanding	'	'	'	'	4,000,000	4,000,000	4,000,000	4,000,000
Preferred stock dividend rate percentage	'	'	'	'	6.88%	6.88%	6.38%	6.38%
Preferred Stock Liquidation preference	'	'	'	'	$100,000,000	$100,000,000	$100,000,000	$100,000,000
General partner, units issued	'	'	83,388,220	82,153,944	'	'	'	'
General partners, units outstanding	'	'	83,388,220	82,153,944	'	'	'	'
Limited partners, units issued	'	'	1,804,200	1,805,200	'	'	'	'
Common units held by limited partners	'	'	1,804,200	1,805,200	'	'	'	'

Consolidated_Statements_of_Ope1

Consolidated Statements of Operations (KILROY REALTY, L.P.) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
REVENUES:	'	'	'	'
Rental income	$115,221	$103,354	$338,911	$303,573
Tenant reimbursements	11,346	9,583	33,399	28,350
Other property income (Note 12)	2,457	608	7,650	6,584
Total revenues	129,024	113,545	379,960	338,507
EXPENSES	'	'	'	'
Property expenses	25,801	24,470	75,448	69,895
Real estate taxes	11,008	10,088	32,728	29,129
Provision for bad debts	58	101	58	196
Ground leases	771	929	2,306	2,665
General and administrative expenses	11,138	10,226	33,806	29,750
Acquisition-related expenses	431	568	1,268	1,387
Depreciation and amortization	50,032	45,804	148,647	138,652
Total expenses	99,239	92,186	294,261	271,674
OTHER (EXPENSES) INCOME:	'	'	'	'
Interest income and other net investment gains/(losses) (Note 11)	-9	673	587	1,084
Interest expense (Note 5)	-16,608	-18,853	-49,880	-58,021
Total other (expenses) income	-16,617	-18,180	-49,293	-56,937
INCOME FROM CONTINUING OPERATIONS	13,168	3,179	39,896	9,896
DISCONTINUED OPERATIONS (Note 13)	'	'	'	'
Income from discontinued operations	548	5,848	2,091	11,199
Gains on dispositions of discontinued operations	5,587	0	110,391	423
Total income from discontinued operations	6,135	5,848	112,482	11,622
NET INCOME	19,303	9,027	152,378	21,518
NET INCOME ATTRIBUTABLE TO KILROY REALTY, L.P.	18,982	8,896	149,367	21,252
NET INCOME AVAILABLE TO COMMON UNITHOLDERS	15,669	5,584	139,429	11,314
Income (loss) from continuing operations available to common unitholders per unit - basic (Note 15)	$0.11	$0	$0.34	($0.02)
Income (loss) from continuing operations available to common unitholders per unit - diluted (Note 15)	$0.11	$0	$0.33	($0.02)
Net income available to common unitholders per unit-basic (Note 15)	$0.18	$0.07	$1.67	$0.13
Net income available to common unitholders per unit-diluted (Note 15)	$0.18	$0.07	$1.63	$0.13
Weighted average common units outstanding - basic (Note 15)	83,161,323	76,768,893	82,525,033	75,750,822
Weighted average common units outstanding - diluted (Note 15)	85,110,456	76,768,893	84,622,622	75,750,822
Kilroy Realty, L.P. [Member]	'	'	'	'
REVENUES:	'	'	'	'
Rental income	115,221	103,354	338,911	303,573
Tenant reimbursements	11,346	9,583	33,399	28,350
Other property income (Note 12)	2,457	608	7,650	6,584
Total revenues	129,024	113,545	379,960	338,507
EXPENSES	'	'	'	'
Property expenses	25,801	24,470	75,448	69,895
Real estate taxes	11,008	10,088	32,728	29,129
Provision for bad debts	58	101	58	196
Ground leases	771	929	2,306	2,665
General and administrative expenses	11,138	10,226	33,806	29,750
Acquisition-related expenses	431	568	1,268	1,387
Depreciation and amortization	50,032	45,804	148,647	138,652
Total expenses	99,239	92,186	294,261	271,674
OTHER (EXPENSES) INCOME:	'	'	'	'
Interest income and other net investment gains/(losses) (Note 11)	-9	673	587	1,084
Interest expense (Note 5)	-16,608	-18,853	-49,880	-58,021
Total other (expenses) income	-16,617	-18,180	-49,293	-56,937
INCOME FROM CONTINUING OPERATIONS BEFORE GAIN ON SALE OF LAND	13,168	3,179	36,406	9,896
Gain on sale of land (Note 13)	0	0	3,490	0
INCOME FROM CONTINUING OPERATIONS	13,168	3,179	39,896	9,896
DISCONTINUED OPERATIONS (Note 13)	'	'	'	'
Income from discontinued operations	548	5,848	2,091	11,199
Gains on dispositions of discontinued operations	5,587	0	110,391	423
Total income from discontinued operations	6,135	5,848	112,482	11,622
NET INCOME	19,303	9,027	152,378	21,518
Net income attributable to noncontrolling interests in consolidated subsidiaries	-59	-47	-201	-178
NET INCOME ATTRIBUTABLE TO KILROY REALTY, L.P.	19,244	8,980	152,177	21,340
Preferred Distributions	-3,313	-3,312	-9,938	-9,938
NET INCOME AVAILABLE TO COMMON UNITHOLDERS	$15,931	$5,668	$142,239	$11,402
Income (loss) from continuing operations available to common unitholders per unit - basic (Note 15)	$0.11	$0	$0.34	($0.02)
Income (loss) from continuing operations available to common unitholders per unit - diluted (Note 15)	$0.11	$0	$0.33	($0.02)
Net income available to common unitholders per unit-basic (Note 15)	$0.18	$0.07	$1.67	$0.13
Net income available to common unitholders per unit-diluted (Note 15)	$0.18	$0.07	$1.63	$0.13
Weighted average common units outstanding - basic (Note 15)	84,965,523	78,590,396	84,329,317	77,574,907
Weighted average common units outstanding - diluted (Note 15)	86,914,656	78,590,396	86,426,906	77,574,907
Dividends declared per common unit	$0.35	$0.35	$1.05	$1.05

Consolidated_Statements_of_Cap

Consolidated Statements of Capital (KILROY REALTY, L.P.) (Kilroy Realty, L.P. [Member], USD $)

9 Months Ended

9 Months Ended

In Thousands, except Share data, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2014

Sep. 30, 2013

Total Partners Capital [Member]

Total Partners Capital [Member]

Noncontrolling Interest [Member]

Noncontrolling Interest [Member]

Partners Capital Preferred Units [Member]

Partners Capital Preferred Units [Member]

Partners Capital Preferred Units [Member]

Partners Capital Preferred Units [Member]

Partners Capital Common Unit [Member]

Partners Capital Common Unit [Member]

Increase (Decrease) in Stockholders' Equity [Roll Forward]

'

'

'

'

'

'

'

'

'

'

'

'

Beginning Balance

$2,516,160

$2,235,933

$2,507,772

$2,232,654

$8,388

$3,279

$192,411

$192,411

$192,411

$192,411

$2,315,361

$2,040,243

Beginning Balance units

'

'

'

'

'

'

'

'

'

'

83,959,144

76,753,484

Net income

152,378

21,518

152,177

21,340

201

178

'

'

'

'

152,177

21,340

Issuance of common units, units

'

'

'

'

'

'

'

'

'

'

370,700

7,210,838

Issuance of common units

22,136

349,951

22,136

349,951

'

'

'

'

'

'

22,136

349,951

Issuance of share-based compensation awards, units

'

'

'

'

'

'

'

'

'

'

'

0

Issuance of share-based compensation awards

1,281

1,075

1,281

1,075

'

'

'

'

'

'

1,281

1,075

Noncash amortization of share-based compensation

10,345

7,096

10,345

7,096

'

'

'

'

'

'

10,345

7,096

Repurchase of common units and restricted stock units, units

'

'

'

'

'

'

'

'

'

'

-48,017

-34,164

Repurchase of common units and restricted stock units

-2,861

-1,803

-2,861

-1,803

'

'

'

'

'

'

-2,861

-1,803

Settlement of restricted stock units, units

'

'

'

'

'

'

'

'

'

'

108,529

4,363

Settlement of restricted stock units for shares of common stock

0

-10

0

-10

'

'

'

'

'

'

0

-10

Common units issued in connection with early exchange of 4.25% Exchangeable Senior Notes (Note 5), units

'

'

'

'

'

'

'

'

'

'

431,270

'

Common units issued in connection with early exchange of 4.25% Exchangeable Senior Notes (Note 5)

223

'

223

'

'

'

'

'

'

'

223

'

Common units received in connection with capped call option transactions (Note 5), units

'

'

'

'

'

'

'

'

'

'

-111,206

'

Common units received in connection with capped call option transactions (Note 5)

0

'

0

'

'

'

'

'

'

'

'

'

Exercise of stock options, net, units

'

'

'

'

'

'

'

'

'

'

482,000

473

Exercise of stock options, net

20,537

128

20,537

128

'

'

'

'

'

'

20,537

128

Contribution by noncontrolling interest in consolidated subsidiary

336

4,885

'

'

336

4,885

'

'

'

'

'

'

Preferred distributions

-9,938

-9,938

-9,938

-9,938

'

'

'

'

'

'

-9,938

-9,938

Distributions declared per common unit ($1.05 per unit)

-90,228

-84,741

-90,228

-84,741

'

'

'

'

'

'

-90,228

-84,741

Ending Balance

$2,620,369

$2,524,094

$2,611,444

$2,515,752

$8,925

$8,342

$192,411

$192,411

$192,411

$192,411

$2,419,033

$2,323,341

Ending Balance units

'

'

'

'

'

'

'

'

'

'

85,192,420

83,934,994

Consolidated_Statements_of_Cap1

Consolidated Statements of Capital (KILROY REALTY, L.P.) (Parenthetical) (Kilroy Realty, L.P. [Member], USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Kilroy Realty, L.P. [Member]	'	'	'	'
Distributions Per Limited Partnership and General Partnership Unit, Outstanding, Basic	$0.35	$0.35	$1.05	$1.05

Consolidated_Statements_of_Cas2

Consolidated Statements of Cash Flows (KILROY REALTY, L.P.) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:	'	'
Net income	$152,378	$21,518
Adjustments to reconcile net income to net cash provided by operating activities (including discontinued operations):	'	'
Depreciation and amortization of building and improvements and leasing costs	148,878	148,982
Increase in provision for bad debts	58	196
Depreciation of furniture, fixtures and equipment	1,731	1,363
Noncash amortization of share-based compensation awards	8,817	6,454
Noncash amortization of deferred financing costs and debt discounts and premiums	3,563	4,047
Noncash amortization of net below market rents (Note 3)	-6,216	-6,015
Gains on dispositions of discontinued operations (Note 13)	-110,391	-423
Gain on sale of land (Note 13)	-3,490	0
Noncash amortization of deferred revenue related to tenant-funded tenant improvements	-7,695	-7,585
Straight-line rents	-15,245	-18,188
Net change in other operating assets	-795	-6,435
Net change in other operating liabilities	25,671	42,844
Insurance proceeds received for property damage	0	-448
Net cash provided by operating activities	197,264	186,310
CASH FLOWS FROM INVESTING ACTIVITIES:	'	'
Expenditures for acquisition of operating properties (Note 2)	-106,125	-202,682
Expenditures for operating properties	-93,977	-83,991
Expenditures for development and redevelopment properties and undeveloped land	-292,803	-222,192
Expenditures for acquisition of development and redevelopment properties (Note 2)	-97,727	-13,269
Net proceeds received from dispositions of operating properties and land (Note 13)	368,381	14,409
Insurance proceeds received from property damage	0	448
Decrease (increase) in acquisition-related deposits	1,000	-4,000
Decrease in restricted cash (Notes 1 and 13)	32,293	229,613
Net cash used in investing activities	-188,958	-281,664
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'
Borrowings on unsecured line of credit	365,000	10,000
Repayments on unsecured line of credit	-410,000	-195,000
Principal payments on secured debt	-7,315	-91,298
Proceeds from issuance of unsecured debt (Note 5)	395,528	299,901
Repayments of unsecured debt (Note 5)	-83,000	0
Repayments for early redemption of exchangeable senior notes (Note 5)	37,092	0
Financing costs	-8,043	-3,975
Repurchase of common stock and restricted stock units	-2,861	-1,813
Proceeds from exercise of stock options (Note 9)	20,537	128
Contributions from noncontrolling interests in consolidated subsidiary	336	0
Distributions paid to common unitholders	-88,540	-82,152
Distributions paid to preferred unitholders	-9,938	-9,938
Net cash provided by financing activities	156,748	275,804
Net increase in cash and cash equivalents	165,054	180,450
Cash and cash equivalents, beginning of period	35,377	16,700
Cash and cash equivalents, end of period	200,431	197,150
SUPPLEMENTAL CASH FLOWS INFORMATION:	'	'
Cash paid for interest, net of capitalized interest of $33,533 and $23,573 as of September 30, 2014 and 2013, respectively	42,633	47,107
NONCASH INVESTING TRANSACTIONS:	'	'
Accrual for expenditures for operating properties and development and redevelopment properties	92,693	79,866
Tenant improvements funded directly by tenants	23,069	5,750
Assumption of other assets and liabilities in connection with operating and development property acquisitions, net	2,300	422
Contribution of land, net of related liabilities, by noncontrolling interest to consolidated subsidiary	0	4,885
Assumption of secured debt in connection with property acquisitions	0	95,496
NONCASH FINANCING TRANSACTIONS:	'	'
Accrual of distributions payable to common unitholders	30,258	29,378
Accrual of distributions payable to preferred unitholders	1,656	1,692
Fair value of share-based compensation awards at equity classification date (Note 9)	18,111	10,347
Kilroy Realty, L.P. [Member]	'	'
CASH FLOWS FROM OPERATING ACTIVITIES:	'	'
Net income	152,378	21,518
Adjustments to reconcile net income to net cash provided by operating activities (including discontinued operations):	'	'
Depreciation and amortization of building and improvements and leasing costs	148,878	148,982
Increase in provision for bad debts	58	196
Depreciation of furniture, fixtures and equipment	1,731	1,363
Noncash amortization of share-based compensation awards	8,817	6,454
Noncash amortization of deferred financing costs and debt discounts and premiums	3,563	4,047
Noncash amortization of net below market rents (Note 3)	-6,216	-6,015
Gains on dispositions of discontinued operations (Note 13)	-110,391	-423
Gain on sale of land (Note 13)	-3,490	0
Noncash amortization of deferred revenue related to tenant-funded tenant improvements	-7,695	-7,585
Straight-line rents	-15,245	-18,188
Net change in other operating assets	-795	-6,435
Net change in other operating liabilities	25,671	42,844
Insurance proceeds received for property damage	0	-448
Net cash provided by operating activities	197,264	186,310
CASH FLOWS FROM INVESTING ACTIVITIES:	'	'
Expenditures for acquisition of operating properties (Note 2)	-106,125	-202,682
Expenditures for operating properties	-93,977	-83,991
Expenditures for development and redevelopment properties and undeveloped land	-292,803	-222,192
Expenditures for acquisition of development and redevelopment properties (Note 2)	-97,727	-13,269
Net proceeds received from dispositions of operating properties and land (Note 13)	368,381	14,409
Insurance proceeds received from property damage	0	448
Decrease (increase) in acquisition-related deposits	1,000	-4,000
Decrease in restricted cash (Notes 1 and 13)	32,293	229,613
Net cash used in investing activities	-188,958	-281,664
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'
Net proceeds from issuance of common units (Note 8)	22,136	349,951
Borrowings on unsecured line of credit	365,000	10,000
Repayments on unsecured line of credit	-410,000	-195,000
Principal payments on secured debt	-7,315	-91,298
Proceeds from issuance of unsecured debt (Note 5)	395,528	299,901
Repayments of unsecured debt (Note 5)	-83,000	0
Repayments for early redemption of exchangeable senior notes (Note 5)	37,092	0
Financing costs	-8,043	-3,975
Repurchase of common stock and restricted stock units	-2,861	-1,813
Proceeds from exercise of stock options (Note 9)	20,537	128
Contributions from noncontrolling interests in consolidated subsidiary	336	0
Distributions paid to common unitholders	-88,540	-82,152
Distributions paid to preferred unitholders	-9,938	-9,938
Net cash provided by financing activities	156,748	275,804
Net increase in cash and cash equivalents	165,054	180,450
Cash and cash equivalents, beginning of period	35,377	16,700
Cash and cash equivalents, end of period	200,431	197,150
SUPPLEMENTAL CASH FLOWS INFORMATION:	'	'
Cash paid for interest, net of capitalized interest of $33,533 and $23,573 as of September 30, 2014 and 2013, respectively	42,633	47,107
NONCASH INVESTING TRANSACTIONS:	'	'
Accrual for expenditures for operating properties and development and redevelopment properties	92,693	79,866
Tenant improvements funded directly by tenants	23,069	5,750
Assumption of other assets and liabilities in connection with operating and development property acquisitions, net	2,300	422
Contribution of land, net of related liabilities, by noncontrolling interest to consolidated subsidiary	0	4,885
Assumption of secured debt in connection with property acquisitions	0	95,496
NONCASH FINANCING TRANSACTIONS:	'	'
Accrual of distributions payable to common unitholders	30,258	29,378
Accrual of distributions payable to preferred unitholders	1,656	1,692
Fair value of share-based compensation awards at equity classification date (Note 9)	$18,111	$10,347

Consolidated_Statements_of_Cas3

Consolidated Statements of Cash Fiows (Kilroy Realty, L.P.) (Parenthetical) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Cash paid for interest - capitalized interest amount	$33,533	$23,573
Kilroy Realty, L.P. [Member]	'	'
Cash paid for interest - capitalized interest amount	$33,533	$23,573

Organization_and_Basis_of_Pres

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization and Basis of Presentation	'
	Organization and Basis of Presentation
	Organization
	Kilroy Realty Corporation (the “Company”) is a self-administered real estate investment trust (“REIT”) active in premier office submarkets along the West Coast. We own, develop, acquire and manage real estate assets, consisting primarily of Class A properties in the coastal regions of Los Angeles, Orange County, San Diego County, the San Francisco Bay Area and greater Seattle, which we believe have strategic advantages and strong barriers to entry. Class A real estate encompasses attractive and efficient buildings of high quality that are attractive to tenants, are well-designed and constructed with above-average material, workmanship and finishes and are well-maintained and managed. We qualify as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”). The Company’s common stock is publicly traded on the New York Stock Exchange (“NYSE”) under the ticker symbol “KRC.”
	We own our interests in all of our real estate assets through Kilroy Realty, L.P. (the “Operating Partnership”) and Kilroy Realty Finance Partnership, L.P. (the “Finance Partnership”). We generally conduct substantially all of our operations through the Operating Partnership. Unless stated otherwise or the context indicates otherwise, the terms “Kilroy Realty Corporation” or the “Company,” “we,” “our,” and “us” refer to Kilroy Realty Corporation and its consolidated subsidiaries and the term “Operating Partnership” refers to Kilroy Realty, L.P. and its consolidated subsidiaries. The descriptions of our business, employees, and properties apply to both the Company and the Operating Partnership.
	Our stabilized portfolio of operating properties was comprised of the following office properties at September 30, 2014:
		Number of		Rentable	Number of	Percentage
		Buildings		Square Feet	Tenants	Occupied
	Stabilized Office Properties	105		13,486,006	526	94.1	%
	Our stabilized portfolio includes all of our properties with the exception of real estate assets held for sale, undeveloped land, development and redevelopment properties currently under construction or committed for construction, and “lease-up” properties. As of September 30, 2014, our stabilized portfolio of operating properties excluded two properties that were classified as held for sale as of that date. We define redevelopment properties as those properties for which we expect to spend significant development and construction costs on the existing or acquired buildings pursuant to a formal plan, the intended result of which is a higher economic return on the property. We define “lease-up” properties as properties we recently developed or redeveloped that have not yet reached 95% occupancy and are within one year following cessation of major construction activities. There were no operating properties in “lease-up” as of September 30, 2014. During the third quarter of 2014, we stabilized a development project in the Sunnyvale submarket of San Francisco, California consisting of three office buildings encompassing 587,429 square feet. As a result, this project is now included in our stabilized portfolio as of September 30, 2014.
	As of September 30, 2014, the following properties were excluded from our stabilized portfolio:
		Number of	Estimated Rentable
		Properties/Projects	Square Feet
	Properties Held for Sale (1)	2	228,788
	Development projects under construction (2)(3)	5	2,000,000
	_______________
	-1	Includes two properties, one located in Orange, California and the other in the San Rafael submarket of San Francisco, California. For additional information see Note 13.
	-2	Estimated rentable square feet upon completion.
	-3	During the third quarter of 2014, we stabilized a development property in the Sunnyvale submarket of San Francisco, California consisting of three office buildings encompassing 587,429 square feet. As a result, this project is now included in our stabilized portfolio as of September 30, 2014.
	As of September 30, 2014, all of our properties and development and redevelopment projects and all of our business was conducted in the state of California with the exception of thirteen office properties located in the state of Washington. All of our properties and development and redevelopment projects are 100% owned, excluding a development project owned by Redwood City Partners, LLC, a consolidated subsidiary (see Note 6).
	As of September 30, 2014, the Company owned a 97.9% common general partnership interest in the Operating Partnership. The remaining 2.1% common limited partnership interest in the Operating Partnership as of September 30, 2014 was owned by non-affiliated investors and certain of our executive officers and directors (see Note 6). Both the general and limited common partnership interests in the Operating Partnership are denominated in common units. Generally, the number of common units held by the Company is equivalent to the number of outstanding shares of the Company’s common stock, and the rights of all the common units to quarterly distributions and payments in liquidation mirror those of the Company’s common stockholders. The common limited partners have certain redemption rights as provided in the Operating Partnership’s Seventh Amended and Restated Agreement of Limited Partnership, as amended, the “Partnership Agreement”) (see Note 6).
	Kilroy Realty Finance, Inc., which is a wholly owned subsidiary of the Company, is the sole general partner of the Finance Partnership and owns a 1.0% common general partnership interest in the Finance Partnership. The Operating Partnership owns the remaining 99.0% common limited partnership interest. Kilroy Services, LLC (“KSLLC”), which is a wholly owned subsidiary of the Operating Partnership, is the entity through which we generally conduct substantially all of our development activities. With the exception of the Operating Partnership and Redwood City Partners, LLC, all of our subsidiaries are wholly owned.
	Basis of Presentation
	The consolidated financial statements of the Company include the consolidated financial position and results of operations of the Company, the Operating Partnership, the Finance Partnership, KSLLC, Redwood City Partners, LLC and all of our wholly owned and controlled subsidiaries. The consolidated financial statements of the Operating Partnership include the consolidated financial position and results of operations of the Operating Partnership, the Finance Partnership, KSLLC, Redwood City Partners, LLC and all wholly-owned and controlled subsidiaries of the Operating Partnership. All intercompany balances and transactions have been eliminated in the consolidated financial statements.
	The accompanying interim financial statements have been prepared by management in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and in conjunction with the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures required for annual financial statements have been condensed or excluded pursuant to SEC rules and regulations. Accordingly, the interim financial statements do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, the accompanying interim financial statements reflect all adjustments of a normal and recurring nature that are considered necessary for a fair presentation of the results for the interim periods presented. However, the results of operations for the interim periods are not necessarily indicative of the results that may be expected for the year ending December 31, 2014. The interim financial statements for the Company and the Operating Partnership should be read in conjunction with the audited consolidated financial statements and notes thereto included in our annual report on Form 10-K/A for the year ended December 31, 2013.
	Certain amounts in the consolidated statements of operations for prior periods have been reclassified to reflect the activity of discontinued operations.
	Variable Interest Entities
	At September 30, 2014, the consolidated financial statements of the Company and the Operating Partnership included one variable interest entity (“VIE”), in which we were deemed to be the primary beneficiary. The VIE, Redwood City Partners, LLC, was established in the second quarter of 2013 in connection with an undeveloped land acquisition. The impact of consolidating the VIE increased the Company’s total assets, liabilities and noncontrolling interests by approximately $98.5 million (of which $98.1 million related to real estate held for investment on our consolidated balance sheet), approximately $20.1 million and approximately $5.2 million, respectively, as of September 30, 2014. As of December 31, 2013, the consolidated financial statements of the Company and the Operating Partnership included four VIEs, in which we were deemed to be the primary beneficiary. One of the VIEs was Redwood City Partners, LLC and the remaining three VIEs were established during the third and fourth quarter of 2013 to facilitate potential Section 1031 Exchanges. During the three months ended March 31, 2014, the Section 1031 Exchanges were successfully completed and the three VIEs were terminated. As a result, $32.2 million of our restricted cash balance at December 31, 2013, which related to prior period disposition proceeds that were set aside to facilitate the Section 1031 Exchanges, was released from escrow. The impact of consolidating the VIEs increased the Company’s total assets, liabilities and noncontrolling interests by approximately $251.8 million (of which $234.5 million related to real estate held for investment on our consolidated balance sheet), approximately $12.1 million and approximately $4.9 million, respectively, as of December 31, 2013.
	Recent Accounting Pronouncements
	On June 19, 2014, the Financial Accounting Standards Board (“FASB”) issued their final standard to amend the accounting guidance for stock compensation tied to performance targets (Accounting Standards Update (“ASU”) No. 2014-12). The issue is the result of a consensus of the FASB Emerging Issues Task Force (Issue No. 13-D). The standard requires that a performance target that could be achieved after the requisite service period be treated as a performance condition, and as a result, this type of performance condition may delay expense recognition until achievement of the performance target is probable. The ASU is effective for all entities for reporting periods (including interim periods) beginning after December 15, 2015, and early adoption is permitted. The Company will adopt the guidance effective January 1, 2016 and the guidance is not anticipated to have a material impact on our consolidated financial statements or notes to our consolidated financial statements.
	On May 28, 2014, the FASB issued their final standard on revenue from contracts with customers. The guidance specifically notes that lease contracts with customers are a scope exception. The standard (ASU No. 2014-09) outlines a single comprehensive model for entities to use in accounting for revenues arising from contracts with customers. The ASU is effective for annual reporting periods (including interim periods), beginning after December 15, 2016, and early adoption is not permitted. The Company will adopt the guidance effective January 1, 2017 and is currently assessing the impact on our consolidated financial statements and notes to our consolidated financial statements.
	On April 10, 2014, the FASB issued final guidance to change the criteria for reporting discontinued operations while enhancing disclosures in this area (ASU No. 2014-08). Under the new guidance, only disposals representing a strategic shift, such as a major line of business, a major geographical area or a major equity investment, should be presented as discontinued operations. The guidance will be applied prospectively to new disposals and new classifications of disposal groups as held for sale after the effective date. The guidance is effective for annual financial statements with fiscal years beginning on or after December 15, 2014 with early adoption permitted for disposals or classifications as held for sale which have not been reported in financial statements previously issued or available for issuance. The Company will adopt the guidance effective January 1, 2015 and the guidance is not anticipated to have a material impact on our consolidated financial statements and notes to our consolidated financial statements.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Acquisitions	'
	Acquisitions
	Operating Properties
	During the nine months ended September 30, 2014, we acquired the one operating office property listed below, from an unrelated third party. The acquisition was funded with proceeds from 2013 and 2014 dispositions (see Note 13).
	Property		Date of Acquisition	Number of	Rentable Square		Occupancy as of September 30, 2014	Purchase
				Buildings	Feet			Price
								(in millions)
	401 Terry Avenue North, Seattle, WA		March 13, 2014	1	140,605		100.00%	$	106.1
	The related assets, liabilities and results of operations of the acquired property are included in the consolidated financial statements as of the date of acquisition. The following table summarizes the estimated fair values of the assets acquired and liabilities assumed on the acquisition date:
		Total 2014
		Acquisitions
		(in thousands)
	Assets
	Land and improvements	$	22,500
	Buildings and improvements (1)	77,046
	Deferred leasing costs and acquisition-related intangible assets (2)	11,199
	Total assets acquired	110,745
	Liabilities
	Deferred revenue and acquisition-related intangible liabilities (3)	4,620
	Total liabilities assumed	4,620
	Net assets and liabilities acquired	$	106,125
	_______________
	-1	Represents buildings, building improvements and tenant improvements.
	-2	Represents in-place leases of approximately $9.3 million (with a weighted average amortization period of seven years) and leasing commissions of approximately $1.9 million (with a weighted average amortization period of seven years) at the time of the acquisition.
	-3	Represents below-market leases of approximately $4.6 million (with a weighted average amortization period of seven years).
	Development Project Sites
	During the nine months ended September 30, 2014, we acquired one undeveloped land site listed below from an unrelated third party. The acquisition was funded with proceeds from the Company’s at-the-market stock offering program (see Note 7) and disposition proceeds (see Note 13).
	Project		Date of Acquisition	Type	Purchase Price
					(in millions)
	Kilroy Mission Bay, San Francisco, CA (1)		23-May-14	Land	$	95
	_______________
	-1	In connection with this acquisition, we also assumed $2.3 million in accrued liabilities which are not included in the purchase price above. As of September 30, 2014, the purchase price and assumed liabilities are included in undeveloped land and construction in progress and the assumed liabilities are included in accounts payable, accrued expenses and other liabilities on our consolidated balance sheets.

Deferred_Leasing_Costs_and_Acq

Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, net	9 Months Ended
	Sep. 30, 2014
Intangible Assets and Liabilities Disclosure [Abstract]	'
deferred Leasing Costs and Acquisition-Related Intangible Assets and Liabilities, net	'
	Deferred Leasing Costs and Acquisition-Related Intangible Assets and Liabilities, net
	The following table summarizes our deferred leasing costs and acquisition-related intangible assets (acquired value of leasing costs, above-market operating leases, in-place leases and below-market ground lease obligation) and intangible liabilities (acquired value of below-market operating leases and above-market ground lease obligation) as of September 30, 2014 and December 31, 2013:
		September 30, 2014			December 31, 2013
		(in thousands)
	Deferred Leasing Costs and Acquisition-Related Intangible Assets, net:
	Deferred leasing costs	$	196,963		$	178,720
	Accumulated amortization	(71,911		)	(63,246		)
	Deferred leasing costs, net	125,052			115,474
	Above-market operating leases	21,926			27,635
	Accumulated amortization	(14,151		)	(14,283		)
	Above-market operating leases, net	7,775			13,352
	In-place leases	94,281			100,318
	Accumulated amortization	(44,522		)	(42,999		)
	In-place leases, net	49,759			57,319
	Below-market ground lease obligation	490			490
	Accumulated amortization	(19		)	(13		)
	Below-market ground lease obligation, net	471			477
	Total deferred leasing costs and acquisition-related intangible assets, net	$	183,057		$	186,622
	Acquisition-Related Intangible Liabilities, net: (1)
	Below-market operating leases	$	69,533		$	69,385
	Accumulated amortization	(31,288		)	(25,706		)
	Below-market operating leases, net	38,245			43,679
	Above-market ground lease obligation	6,320			6,320
	Accumulated amortization	(298		)	(223		)
	Above-market ground lease obligation, net	6,022			6,097
	Total acquisition-related intangible liabilities, net	$	44,267		$	49,776
	_______________
	-1	Included in deferred revenue and acquisition-related intangible liabilities, net in the consolidated balance sheets.
	The following table sets forth amortization related to deferred leasing costs and acquisition-related intangibles, including amounts attributable to discontinued operations, for the three and nine months ended September 30, 2014 and 2013:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
		(in thousands)
	Deferred leasing costs (1)	$	7,132		$	6,945		$	20,683		$	20,882
	Above-market operating leases (2)	1,305			1,417			4,230			4,214
	In-place leases (1)	5,169			7,677			17,090			22,546
	Below-market ground lease obligation (3)	2			2			6			6
	Below-market operating leases (4)	(2,940		)	(3,355		)	(10,054		)	(10,229		)
	Above-market ground lease obligation (5)	(26		)	(25		)	(76		)	(76		)
	Total	$	10,642		$	12,661		$	31,879		$	37,343
	_______________
	-1	The amortization of deferred leasing costs related to lease incentives is recorded to rental income and other deferred leasing costs and in-place leases is recorded to depreciation and amortization expense in the consolidated statements of operations for the periods presented.
	-2	The amortization of above-market operating leases is recorded as a decrease to rental income in the consolidated statements of operations for the periods presented.
	-3	The amortization of the below-market ground lease obligation is recorded as an increase to ground lease expense in the consolidated statements of operations for the periods presented.
	-4	The amortization of below-market operating leases is recorded as an increase to rental income in the consolidated statements of operations for the periods presented.
	-5	The amortization of the above-market ground lease obligation is recorded as a decrease to ground lease expense in the consolidated statements of operations for the periods presented.
	The following table sets forth the estimated annual amortization expense related to deferred leasing costs and acquisition-related intangibles as of September 30, 2014 for future periods:
	Year	Deferred Leasing Costs			Above-Market Operating Leases (1)			In-Place Leases			Below-Market Ground Lease Obligation (2)			Below-Market Operating Leases (3)			Above-Market Ground Lease Obligation (4)
		(in thousands)
	Remaining 2014	$	6,936		$	993		$	4,274		$	2		$	(2,851	)	$	(26	)
	2015	24,851			2,530			13,131			8			(9,567		)	(101		)
	2016	22,045			1,503			10,080			8			(7,847		)	(101		)
	2017	19,163			1,241			8,440			8			(6,780		)	(101		)
	2018	15,748			831			5,532			8			(5,177		)	(101		)
	Thereafter	36,309			677			8,302			437			(6,023		)	(5,592		)
	Total	$	125,052		$	7,775		$	49,759		$	471		$	(38,245	)	$	(6,022	)
	_______________
	-1	Represents estimated annual amortization related to above-market operating leases. Amounts will be recorded as a decrease to rental income in the consolidated statements of operations.
	-2	Represents estimated annual amortization related to below-market ground lease obligations. Amounts will be recorded as an increase to ground lease expense in the consolidated statements of operations.
	-3	Represents estimated annual amortization related to below-market operating leases. Amounts will be recorded as an increase to rental income in the consolidated statements of operations.
	-4	Represents estimated annual amortization related to above-market ground lease obligations. Amounts will be recorded as a decrease to ground lease expense in the consolidated statements of operations.

Receivables

Receivables	9 Months Ended
	Sep. 30, 2014
Receivables [Abstract]	'
Receivables	'
	Receivables
	Current Receivables, net
	Current receivables, net is primarily comprised of contractual rents and other lease-related obligations due from tenants. The balance consisted of the following as of September 30, 2014 and December 31, 2013:
		September 30, 2014 (1)			December 31, 2013
		(in thousands)
	Current receivables	$	8,626		$	12,866
	Allowance for uncollectible tenant receivables	(2,183		)	(2,123		)
	Current receivables, net	$	6,443		$	10,743
	______________
	-1	Excludes current receivables, net related to properties held for sale at September 30, 2014.
	Deferred Rent Receivables, net
	Deferred rent receivables, net consisted of the following as of September 30, 2014 and December 31, 2013:
		September 30, 2014 (1)			December 31, 2013
		(in thousands)
	Deferred rent receivables	$	141,899		$	129,198
	Allowance for deferred rent receivables	(1,989		)	(2,075		)
	Deferred rent receivables, net	$	139,910		$	127,123
	______________
	-1	Excludes deferred rent receivables, net related to properties held for sale at September 30, 2014.

Secured_and_Unsecured_Debt_of_

Secured and Unsecured Debt of the Operating Partnership (Kilroy Realty, L.P. [Member])	9 Months Ended
	Sep. 30, 2014
Kilroy Realty, L.P. [Member]	'
Debt Instrument [Line Items]	'
Secured and Unsecured Debt of the Operating Partnership	'
	Secured and Unsecured Debt of the Operating Partnership
	Secured Debt
	The following table sets forth the composition of our secured debt as of September 30, 2014 and December 31, 2013:
	Type of Debt	Annual Stated Interest Rate (1)		GAAP	Maturity Date		September 30, 2014 (3)				December 31, 2013 (3)
				Effective Rate (1)(2)
							(in thousands)
	Mortgage note payable	4.27%		4.27%	Feb-18		$	131,363			$	133,117
	Mortgage note payable (4)	4.48%		4.48%	Jul-27		97,000				97,000
	Mortgage note payable (4)	6.05%		3.50%	Jun-19		90,065				92,502
	Mortgage note payable	6.51%		6.51%	Feb-17		66,907				67,663
	Mortgage note payable (4)	5.23%		3.50%	Jan-16		53,243				54,570
	Mortgage note payable (4)	5.57%		3.25%	Feb-16		40,611				41,654
	Mortgage note payable (4)	5.09%		3.50%	Aug-15		34,446				34,845
	Mortgage note payable (4)	4.94%		4.00%	Apr-15		26,629				27,641
	Mortgage note payable	7.15%		7.15%	May-17		7,185				8,972
	Other	Various		Various	Various		2,447				2,470
	Total						$	549,896			$	560,434
	______________
	-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 and discounts for the periods presented.
	-4	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.
	Although our mortgage loans are secured and non-recourse to the Company and the Operating Partnership, the Company provides limited customary secured debt guarantees for items such as voluntary bankruptcy, fraud, misapplication of payments and environmental liabilities.
	4.25% Exchangeable Senior Notes
	The table below summarizes the balance and significant terms of the Company’s 4.25% Exchangeable Notes due November 2014 (the “4.25% Exchangeable Notes”) outstanding as of September 30, 2014 and December 31, 2013.
		4.25% Exchangeable Notes
		September 30,			December 31,
		2014			2013
		(in thousands)
	Principal amount	$	135,481		$	172,500
	Unamortized discount	(432		)	(4,128		)
	Net carrying amount of liability component	$	135,049		$	168,372
	Carrying amount of equity component (1)	$15,578			$19,835
	Issuance date	Nov-09
	Maturity date	Nov-14
	Stated coupon rate (2)	4.25%
	Effective interest rate (3)	7.13%
	Exchange rate per $1,000 principal value of the 4.25% Exchangeable Notes, as adjusted (3)	27.8307
	Exchange price, as adjusted (4)	$35.93
	Number of shares on which the aggregate consideration to be delivered on conversion is determined (4)	3,770,531			4,800,796
	_______________
	-1	The $15.6 million carrying amount of the equity component at September 30, 2014 represents the proportionate amount of the initial $19.8 million carrying value of the equity component allocated to the remaining $135.5 million outstanding principal balance of the 4.25% Exchangeable Notes at September 30, 2014.
	-2	Interest on the 4.25% Exchangeable Notes is payable semi-annually in arrears on May 15th and November 15th of each year.
	-3	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.
	-4	The exchange rate, exchange price and the number of shares to be delivered upon conversion are subject to adjustment under certain circumstances including increases in our common dividends.
	During the nine months ended September 30, 2014, the Company settled early exchanges of the 4.25% Exchangeable Notes with an aggregate principal amount of $37.0 million. For these exchanges, the number of shares issued in excess of the exchange value was calculated on a proportionate basis for each day of a 30 trading-day observation following the exchange date. For the exchange settlements, the Company paid the noteholders a total of $37.0 million in cash for the principal amount and issued to the noteholders a total of 431,270 shares of our common stock for the excess exchange value. As a result of the exchanges, the Company exercised the equivalent proportionate amount of its capped call options and, and in connection received 111,206 shares of our common stock from the counterparties. This reduced the shares of common stock issued in connection with the exchanges to 320,064 shares.
	Upon exchange of the balance of the 4.25% Exchangeable Notes at maturity, the holders will receive (i) cash up to the principal amount of the 4.25% Exchangeable Notes and (ii) to the extent the exchange value exceeds the principal amount of the 4.25% Exchangeable Notes, shares of the Company’s common stock. Any shares of common stock delivered for settlement will be based on a daily exchange value calculated on a proportionate basis for each day of a 30 trading-day observation period.
	The 4.25% Exchangeable Notes are exchangeable for shares of the Company’s common stock prior to maturity only upon the occurrence of certain events. During the three and nine months ended September 30, 2014, the closing sale price per share of the common stock of the Company was more than 130% of the exchange price per share of the Company’s common stock for at least 20 trading days in the specified period. As a result, for the three month period ended September 30, 2014, the 4.25% Exchangeable Notes were exchangeable at the exchange rate stated above and may be exchangeable thereafter, if one or more of the events were again to occur during future measurement periods.
	In connection with the offering of the 4.25% Exchangeable Notes, we entered into capped call option transactions (“capped calls”) to mitigate the dilutive impact of the potential exchange of the 4.25% Exchangeable Notes. The capped calls, as amended, are separate transactions entered into by us with the relevant financial institutions, are not part of the terms of the 4.25% Exchangeable Notes, and do not affect the holders’ rights under the 4.25% Exchangeable Notes. The strike prices of the capped calls, which are subject to customary anti-dilution adjustments, correspond to the exchange prices of the applicable 4.25% Exchangeable Notes. The table below summarizes our capped call option positions for the 4.25% Exchangeable Notes as of September 30, 2014 and December 31, 2013.
		4.25% Exchangeable Notes
		September 30, 2014			December 31, 2013
	Referenced shares of common stock (1)	3,770,531			4,800,796
	Exchange price, including effect of capped calls	$	42.81		$	42.81
	________________________
	-1	The referenced shares of common stock decreased during the nine months ended September 30, 2014 as a result of the settled exchanges of the 4.25% Exchangeable Notes totaling $37.0 million.
	The capped calls are expected to terminate upon the earlier of the maturity date of the 4.25% Exchangeable Notes or upon the date upon which the 4.25% Exchangeable Notes are no longer outstanding resulting from an exchange or repurchase by us. The initial cost of the capped calls were recorded as a reduction to additional paid-in capital.
	For the three and nine months ended September 30, 2014 and 2013, 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 below:
		Three Months Ended September 30,			Nine Months Ended September 30,
		2014		2013	2014		2013
	Per share average trading price of the Company’s common stock	$62.06		$51.57	$59.27		$52.42
	The 4.25% Exchangeable Notes were exchangeable as of September 30, 2014 and September 30, 2013. If the 4.25% Exchangeable Notes outstanding as of those dates were exchanged, the approximate fair value of the shares upon exchange at September 30, 2014 and 2013, using the per share average trading price presented in the table above, would have been as follows:
		Three Months Ended September 30,							Nine Months Ended September 30,
		2014			2013				2014				2013
	(in thousands)
Approximate fair value of shares upon exchange	$	229,840		$	245,200			$	223,732			$	248,000
Principal amount of the 4.25% Exchangeable Notes	135,481			172,500				135,481				172,500
Approximate fair value in excess amount of principal amount	$	94,359		$	72,700			$	88,251			$	75,500
See Notes 14 and 15 for a discussion of the impact of the 4.25% Exchangeable Notes on our diluted earnings per share and unit calculations for the periods presented.
Interest Expense for the 4.25% Exchangeable Notes
The unamortized discount on the 4.25% Exchangeable Notes is accreted as additional interest expense from the date of issuance through the maturity date of the applicable Exchangeable Notes. The following table summarizes the total interest expense attributable to the 4.25% Exchangeable Notes based on the respective effective interest rates, before the effect of capitalized interest, for the three and nine months September 30, 2014 and 2013:
	Three Months Ended September 30,							Nine Months Ended September 30,
	2014			2013				2014				2013
	(in thousands)
Contractual interest payments	$	1,439		$	1,833			$	4,908			$	5,498
Amortization of discount	1,004			1,116				3,337				3,291
Interest expense attributable to the 4.25% Exchangeable Notes	$	2,443		$	2,949			$	8,245			$	8,789
Unsecured Senior Notes
In July 2014, the Operating Partnership issued $400.0 million aggregate principal amount of unsecured senior notes in a registered public offering. The outstanding balance of the unsecured senior notes is included in unsecured debt, net of the initial issuance discount of $4.4 million, on our consolidated balance sheets. The unsecured senior notes, which are scheduled to mature on August 15, 2029, require semi-annual interest payments each February and August based on a stated annual interest rate of 4.250%. The Company used a portion of the net proceeds for general corporate purposes, including the repayment of borrowings under the Operating Partnership’s revolving credit facility.
The following table summarizes the balance and significant terms of the registered unsecured senior notes issued by the Operating Partnership as of September 30, 2014 and December 31, 2013:
								Principal Amount as of
	Issuance date		Maturity date	Stated		Effective interest rate (1)		September 30,				December 31,
				coupon rate				2014				2013
								(in thousands)
4.250% Unsecured Senior Notes (2)	Jul-14		Aug-29	4.25%		4.35%		$	400,000			$	—
Unamortized discount								(4,422		)		—
Net carrying amount								$	395,578			$	—
3.800% Unsecured Senior Notes (3)	Jan-13		Jan-23	3.80%		3.80%		$	300,000			$	300,000
Unamortized discount								(82		)		(90		)
Net carrying amount								$	299,918			$	299,910
4.800% Unsecured Senior Notes (4)	Jul-11		Jul-18	4.80%		4.83%		$	325,000			$	325,000
Unamortized discount								(283		)		(339		)
Net carrying amount								$	324,717			$	324,661
6.625% Unsecured Senior Notes (5)	May-10		Jun-20	6.63%		6.74%		$	250,000			$	250,000
Unamortized discount								(1,207		)		(1,367		)
Net carrying amount								$	248,793			$	248,633
5.000% Unsecured Senior Notes (6)	Nov-10		Nov-15	5.00%		5.01%		$	325,000			$	325,000
Unamortized discount								(44		)		(73		)
Net carrying amount								$	324,956			$	324,927
________________________
-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 the 4.250% unsecured senior notes is payable semi-annually in arrears on February 15th and August 15th of each year.
-3	Interest on the 3.800% unsecured senior notes is payable semi-annually in arrears on January 15th and July 15th of each year.
-4	Interest on the 4.800% unsecured senior notes is payable semi-annually in arrears on January 15th and July 15th of each year.
-5	Interest on the 6.625% unsecured senior notes is payable semi-annually in arrears on June 1st and December 1st of each year.
-6	Interest on the 5.000% unsecured senior notes is payable semi-annually in arrears on May 3rd and November 3rd of each year.
In addition to the registered unsecured senior notes listed above, we also had outstanding Series B unsecured senior notes with an aggregate principal balance of $83.0 million and effective interest rate of 6.45% as of December 31, 2013. We repaid the notes upon maturity in August 2014.
Unsecured Revolving Credit Facility and Term Loan Facility
In the second quarter of 2014, the Company amended the terms of our unsecured revolving credit facility and the Company’s $150.0 million term loan facility. The amendment increased the size of the Company’s unsecured line of credit to $600.0 million, extended the maturity to July 2019 on both the credit facility and term loan facility, reduced the annual interest rate on the unsecured revolving credit facility to LIBOR plus 1.250% and reduced the annual interest rate on the term loan facility to LIBOR plus 1.400%. The amendment did not affect the outstanding borrowings under the credit facility.
The following table summarizes the balance and terms of our unsecured revolving credit facility as of September 30, 2014 and December 31, 2013:
	September 30, 2014			December 31, 2013
	(in thousands)
Outstanding borrowings	$	—		$	45,000
Remaining borrowing capacity	600,000			455,000
Total borrowing capacity (1)	$	600,000		$	500,000
Interest rate (2)(3)	—		%	1.62		%
Facility fee-annual rate (4)	0.25%			0.30%
Maturity date	Jul-19			Apr-17
_______________
-1	We may elect to borrow, subject to bank approval and obtaining commitments for any additional borrowing capacity, up to an additional $300.0 million under an accordion feature under the terms of the unsecured revolving credit facility and term loan facility.
-2	Our revolving credit facility interest rate was calculated based on an annual rate of LIBOR plus 1.250% as of September 30, 2014.
-3	Our revolving credit facility interest rate was calculated based on an annual rate of LIBOR plus 1.450% as of December 31, 2013.
-4	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 September 30, 2014, $6.2 million of deferred financing costs remains to be amortized through the amended maturity date of our unsecured revolving credit facility.
The Company intends to borrow amounts under the unsecured revolving credit facility from time to time for general corporate purposes, to fund potential acquisitions, to finance development and redevelopment expenditures and to potentially repay long-term debt.
The following table summarizes the balance and terms of our term loan facility as of September 30, 2014 and December 31, 2013:
	September 30, 2014			December 31, 2013
	(in thousands)
Outstanding borrowings	$	150,000		$	150,000
Interest rate	1.4		%	1.75		%
Maturity date	Jul-19			Mar-16
Debt Covenants and Restrictions
The revolving credit facility, the term loan facility, the unsecured senior notes, and certain other secured debt arrangements contain covenants and restrictions requiring us to meet certain financial ratios and reporting requirements. Some of the more restrictive financial covenants include a maximum ratio of total debt to total asset value, a minimum fixed-charge coverage ratio, a minimum unsecured debt ratio and a minimum unencumbered asset pool debt service coverage ratio. Noncompliance with one or more of the covenants and restrictions could result in the full principal balance of the associated debt becoming immediately due and payable. We believe we were in compliance with all of our debt covenants as of September 30, 2014.
Debt Maturities
The following table summarizes the stated debt maturities and scheduled amortization payments, excluding debt discounts and premiums, as of September 30, 2014:
Year	(in thousands)
Remaining 2014	$	138,009
2015	395,104
2016	99,431
2017	71,748
2018	451,728
Thereafter	1,268,013
Total (1)	$	2,424,033
________________________
-1	Includes gross principal balance of outstanding debt before impact of net unamortized premiums totaling approximately $4.9 million.
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 three and nine months ended September 30, 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.
	Three Months Ended September 30,							Nine Months Ended September 30,
	2014			2013				2014				2013
	(in thousands)
Gross interest expense	$	29,936		$	27,942			$	85,740			$	83,322
Capitalized interest and loan fees	(13,328		)	(9,089		)		(35,860		)		(25,301		)
Interest expense	$	16,608		$	18,853			$	49,880			$	58,021

Noncontrolling_Interests_on_th

Noncontrolling Interests on the Company's Consolidated Financial Statements	9 Months Ended
	Sep. 30, 2014
Noncontrolling Interest [Abstract]	'
Noncontrolling Interests on the Company's Consolidated Financial Statements	'
	Noncontrolling Interests on the Company’s Consolidated Financial Statements
	Common Units of the Operating Partnership
	The Company owned a 97.9%, 97.8% and 97.8% common general partnership interest in the Operating Partnership as of September 30, 2014, December 31, 2013 and September 30, 2013, respectively. The remaining 2.1%, 2.2% and 2.2% common limited partnership interest as of September 30, 2014, December 31, 2013 and September 30, 2013, respectively, was owned by non-affiliate investors and certain of our executive officers and directors in the form of noncontrolling common units. There were 1,804,200, 1,805,200 and 1,821,503 common units outstanding held by these investors, executive officers and directors as of September 30, 2014, December 31, 2013 and September 30, 2013, respectively.
	The noncontrolling common units may be redeemed by unitholders for cash. Except under certain circumstances, we, at our option, may satisfy the cash redemption obligation with shares of the Company’s common stock on a one-for-one basis. If satisfied in cash, the value for each noncontrolling common unit upon redemption is the amount equal to the average of the closing quoted price per share of the Company’s common stock, par value $.01 per share, as reported on the NYSE for the ten trading days immediately preceding the applicable redemption date. The aggregate value upon redemption of the then-outstanding noncontrolling common units was $107.8 million and $90.8 million as of September 30, 2014 and December 31, 2013,
	respectively. This redemption value does not necessarily represent the amount that would be distributed with respect to each noncontrolling common unit in the event of our termination or liquidation. In the event of our termination or liquidation, it is expected in most cases that each common unit would be entitled to a liquidating distribution equal to the liquidating distribution payable in respect of each share of the Company’s common stock.
	Noncontrolling Interest in Consolidated Variable Interest Entity
	The noncontrolling interest in consolidated subsidiary represents the third party equity interest in Redwood City Partners, LLC, a consolidated VIE. This noncontrolling interest was $5.2 million and $4.9 million at September 30, 2014 and December 31, 2013, respectively.

Stockholders_Equity_of_the_Com

Stockholders' Equity of the Company	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Stockholders' Equity of the Company	'
	Stockholders’ Equity of the Company
	At-The-Market Stock Offering Program
	Under our at-the-market stock offering program, which commenced in July 2011, we may offer and sell shares of our common stock having an aggregate gross sales price of up to $200.0 million from time to time in “at-the-market” offerings. There were no sales of our common stock under our at-the-market offering program for the three months ended September 30, 2014. The following table sets forth information regarding sales of our common stock under our at-the-market offering program for the nine months ended September 30, 2014:
		Nine months
		ended September 30, 2014
		(in millions, except share
		and per share data)
	Shares of common stock sold during the year	370,700
	Weighted average price per common share	$	61.01
	Aggregate gross proceeds	$	22.6
	Aggregate net proceeds after sales agent compensation	$	22.3
	The proceeds from the sales were used to fund acquisitions and development and redevelopment expenditures and for general corporate purposes. Since commencement of the program, we have sold 2,553,961 shares of common stock having an aggregate gross sales price of $127.9 million. As of September 30, 2014, shares of common stock having an aggregate gross sales price of up to $72.1 million remain available to be sold under this program. Actual future sales will depend upon a variety of factors, including but not limited to market conditions, the trading price of the Company’s common stock and our capital needs. We have no obligation to sell the remaining shares available for sale under this program.

Partners_Capital_of_the_Operat

Partners' Capital of the Operating Partnership	9 Months Ended
	Sep. 30, 2014
Partners' Capital Notes [Abstract]	'
Common Units of the Operating Partnership	'
	Partners’ Capital of the Operating Partnership
	Common Units Outstanding
	The following table sets forth the number of common units held by the Company and the number of common units held by non-affiliate investors and certain of our executive officers and directors in the form of noncontrolling common units as well as the ownership interest held on each respective date:
		September 30, 2014		December 31, 2013		September 30, 2013
	Company owned common units in the Operating Partnership	83,388,220		82,153,944		82,113,491
	Company owned general partnership interest	97.9	%	97.8	%	97.8	%
	Noncontrolling common units of the Operating Partnership	1,804,200		1,805,200		1,821,503
	Ownership interest of noncontrolling interest	2.1	%	2.2	%	2.2	%
	For a further discussion of the noncontrolling common units as of September 30, 2014 and December 31, 2013, refer to Note 6.

ShareBased_Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Share-Based Compensation	'
	Share-Based Compensation
	Stockholder Approved Equity Compensation Plans
	As of September 30, 2014, we maintained one share-based incentive compensation plan, the Kilroy Realty 2006 Incentive Award Plan as amended (the “2006 Plan”). As of March 31, 2014, no shares were available for grant under the 2006 Plan. At our Annual Meeting of Stockholders, on May 22, 2014, stockholders approved an amendment of the 2006 Plan, which included an increase in the share limit to 7,120,000 shares. As of September 30, 2014, 728,865 shares were available for grant under the amended 2006 Plan.
	2014 Share-Based Compensation Grants
	On January 29, 2014, the Executive Compensation Committee of the Company’s Board of Directors awarded to certain officers of the Company under the 2006 Plan of 236,604 restricted stock units (“RSUs”), 119,098 RSUs that are subject to market and performance-based vesting requirements (the “2014 Performance-Based RSU Grant”) and 117,506 RSUs that are subject to time-based vesting requirements (the “2014 Time-Based RSU Grant”). As of the RSU grant date, an insufficient number of shares were available under the 2006 Plan to settle these RSUs in stock and the RSUs were subject to liability accounting. As discussed above, on May 22, 2014 we received stockholder approval for an increase to our share limit which resulted in a sufficient number of shares authorized by our stockholders for issuance under the 2006 Plan to cover settlement of these awards. As a result, as of May 22, 2014 given we have the ability to deliver shares to settle the RSUs, we reclassified these awards as equity awards and re-measured the fair value of the awards as of that date.
	2014 Performance-Based RSU Grant
	The 2014 Performance-Based RSUs are scheduled to vest at the end of a three year period based upon the achievement of pre-established levels of FFO per share (the “performance condition”) for the year ended December 31, 2014 and also based upon the average annual relative total stockholder return targets (the “market condition”) for the three year period ending December 31, 2016. The 2014 Performance-Based RSUs are also subject to a three-year service vesting provision and will cliff vest at the end of the three-year period. The number of 2014 Performance-Based RSUs ultimately earned, and therefore the compensation costs for these awards, could fluctuate from the 119,098 RSUs granted based upon the levels of achievement for both the FFO and relative stockholder return metrics. During the 2014 performance period, the estimate of the number of awards earned were evaluated quarterly based on our forecasted level of achievement of the FFO hurdle. Compensation expense for the 2014 Performance-Based RSU Grant will be recorded on a straight-line basis over the three year period.
	Each 2014 Performance-Based RSU represents the right to receive one share of our common stock in the future. As of March 31, 2014, we recorded compensation expense for the award based upon the fair value at period end of $63.44, as we had an insufficient number of shares available for issuance under the 2006 Plan at that time. As discussed above, upon stockholder approval of the amended 2006 Plan on May 22, 2014, we were required to re-measure the fair value of the 2014 Performance-Based RSU Grant and record compensation expense based on the fair value at that date for the cumulative portion of the performance period that had elapsed. The total fair value of the 2014 Performance-Based RSU Grant was $7.7 million at May 22, 2014 and was calculated using a Monte Carlo simulation pricing model based on the assumptions in the table below. The determination of the fair value of the 2014 Performance-Based RSU Grant takes into consideration the likelihood of achievement of both the performance condition and the market condition discussed above. For the nine months ended September 30, 2014, we recorded compensation expense based upon the $65.03 fair value at May 22, 2014. The following table summarizes the assumptions utilized in the Monte Carlo simulation pricing model:
		Fair Value Assumptions
	Fair value per share at May 22, 2014	$65.03
	Expected share price volatility	24.00%
	Risk-free interest rate	0.61%
	Remaining expected life	2.6
	The computation of expected volatility is based on a blend of the historical volatility of our shares of common stock over approximately five years as that is expected to be most consistent with future volatility and equates to a time period twice as long as the approximate two and a half year remaining performance period of the RSUs and implied volatility data based on the observed pricing of six month publicly-traded options on our shares of common stock. The risk-free interest rate is based on the yield curve on zero-coupon U.S. Treasury STRIP securities in effect at May 22, 2014. The expected dividend yield is estimated by examining
	the average of the historical dividend yield levels over the remaining 2.6 year term of the RSUs and our current annualized dividend yield as of May 22, 2014. The expected life of the RSUs is equal to the remaining 2.6 year vesting period at May 22, 2014.
	2014 Time-Based RSU Grant
	The 2014 Time-Based RSUs are scheduled to vest in four equal installments beginning on January 5, 2015 through January 5, 2018. Compensation expense for the 2014 Time-Based RSUs will be recognized on a straight-line basis over the four year service vesting period. Each 2014 Time-Based RSUs represents the right to receive one share of our common stock in the future. As of March 31, 2014, we recorded compensation expense for the award based upon the fair value at period end of $51.64, because at that time an insufficient number of shares were available for issuance under the 2006 Plan. As discussed above, upon stockholder approval of the amended 2006 Plan on May 22, 2014, we were required to re-measure the fair value of the 2014 Time-Based RSU Grant and record compensation expense based on the fair value at that date, for the cumulative portion of the performance period that had elapsed. The total fair value was $7.1 million, which was based on the $60.16 closing share price of the Company’s common stock on the NYSE on May 22, 2014.
	Share-Based Award Activity
	During the nine months ended September 30, 2014, 482,000 non-qualified stock options were exercised and issued at an exercise price per share equal to $42.61. The total shares exercised include 22,162 common shares that were tendered in accordance with the terms of the 2006 Plan to satisfy minimum statutory tax withholding requirements and exercise price related to the non-qualified stock options exercised. We accept the return of shares at the current quoted closing share price of the Company’s common stock to satisfy tax obligations and cover the exercise price.
	Share-Based Compensation Cost Recorded During the Period
	The total compensation cost for all share-based compensation programs was $4.0 million and $2.5 million for the three months ended September 30, 2014 and 2013, respectively, and $10.3 million and $7.2 million for the nine months ended September 30, 2014 and 2013, respectively. Of the total share-based compensation costs, $0.6 million and $0.2 million was capitalized as part of real estate assets for the three months ended September 30, 2014 and 2013, respectively, and $1.5 million and $0.6 million was capitalized as part of real estate assets for the nine months ended September 30, 2014 and 2013, respectively. As of September 30, 2014, there was approximately $34.4 million of total unrecognized compensation cost related to nonvested incentive awards granted under share-based compensation arrangements that is expected to be recognized over a weighted-average period of 2.8 years. The remaining compensation cost related to these nonvested incentive awards had been recognized in periods prior to September 30, 2014.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	General
	As of September 30, 2014, we had commitments of approximately $514.7 million, excluding our ground lease commitments, for contracts and executed leases directly related to our operating and redevelopment properties.
	Environmental Matters
	We follow the policy of monitoring our properties for the presence of hazardous or toxic substances. While there can be no assurance that a material environmental liability does not exist, we are not currently aware of any environmental liability with respect to the properties that would have a material adverse effect on our financial condition, results of operations and cash flow. Further, we are not aware of any environmental liability or any unasserted claim or assessment with respect to an environmental liability that we believe would require additional disclosure or the recording of a loss contingency.

Fair_Value_Measurements_and_Di

Fair Value Measurements and Disclosures	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements and Disclosures	'
	Fair Value Measurements and Disclosures
	Assets and Liabilities Reported at Fair Value
	The only assets we record at fair value on a recurring basis on our consolidated financial statements are the marketable securities related to our deferred compensation plan. The following table sets forth the fair value of our marketable securities as of September 30, 2014 and December 31, 2013:
		Fair Value (Level  1) (1)
		September 30, 2014			December 31, 2013
	Description	(in thousands)
	Marketable securities (2)	$	12,076		$	10,008
	_______________
	-1	Based on quoted prices in active markets for identical securities.
	-2	The marketable securities are held in a limited rabbi trust.
	We report the change in the fair value of the marketable securities at the end of each accounting period in interest income and other net investment gains (losses) in the consolidated statements of operations. We adjust the related deferred compensation plan liability to fair value at the end of each accounting period based on the performance of the benchmark funds selected by each participant, which results in a corresponding increase or decrease to compensation cost for the period.
	The following table sets forth the net gain (loss) on marketable securities recorded during the three and nine months ended September 30, 2014 and 2013:
		Three Months Ended September 30,					Nine Months Ended September 30,
		2014			2013		2014		2013
	Description	(in thousands)
	Net (loss) gain on marketable securities	$	(39	)	$	669	$	507	$	995
	Financial Instruments Disclosed at Fair Value
	The following table sets forth the carrying value and the fair value of our other financial instruments as of September 30, 2014 and December 31, 2013:
		September 30, 2014					December 31, 2013
		Carrying			Fair		Carrying		Fair
		Value			Value		Value		Value
		(in thousands)
	Liabilities
	Secured debt (1)	$	549,896		$	557,217	$	560,434	$	568,760
	Exchangeable senior notes, net (1)	135,049			135,770		168,372		178,190
	Unsecured debt, net (2)	1,743,962			1,825,725		1,431,132		1,523,052
	Unsecured line of credit (1)	—			—		45,000		45,012
	_______________
	-1	Fair value calculated using Level II inputs, which are based on model-derived valuations in which significant inputs and significant value drivers are observable in active markets.
	-2	Fair value calculated using Level I and Level II inputs. Level I inputs are based on quoted prices for identical instruments in active markets. The carrying value and fair value of the Level I instruments was $1,269.2 million and $1,325.0 million, respectively, as of September 30, 2014. The carrying value and fair value of the Level I instruments as of December 31, 2013, was $873.5 million and $929.3 million, respectively. The carrying value and fair value of the Level II instruments was $474.7 million and $500.6 million, respectively, as of September 30, 2014. The carrying value and fair value of the Level II instruments as of December 31, 2013, was $557.7 million and $593.7 million, respectively.

Other_Significant_Events_Other

Other Significant Events Other Significant Events	9 Months Ended
	Sep. 30, 2014
Other Income and Expenses [Abstract]	'
Other Significant Events	'
	Other Significant Events
	In January 2014, a tenant at one of our San Diego, California operating properties exercised an early lease termination clause as permitted under the terms of their lease. As a result, the lease which encompasses approximately 79,000 rentable square feet and was scheduled to expire in February 2020, terminated during the three months ended September 30, 2014. The total lease termination fee of $5.7 million, of which the Company recorded $2.0 million and $5.7 million during the three and nine months ended September 30, 2014, respectively, was recorded as other property income on a straight line basis through the early lease termination date. The Company received the cash payment of the lease termination fee of $5.7 million during the three months ended September 30, 2014. During the three and nine months ended September 30, 2014, the Company also recognized approximately $0.4 million and $1.3 million as a reduction to rental income due to the accelerated amortization of the deferred rent receivable and above market lease for this tenant.

Discontinued_Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]	'
Discontinued Operations	'
	Discontinued Operations and Land Dispositions
	Properties Held for Sale
	As of September 30, 2014, the following properties were classified as held for sale:
	Location		City/Submarket		Property Type		Number of Buildings	Rentable Square Feet
								(unaudited)
	4040 Civic Center Dr, San Rafael, CA		San Rafael		Office		1	130,237
	999 Town & Country Rd, Orange, CA		Orange		Office		1	98,551
	Total properties held for sale						2	228,788
	The major classes of assets and liabilities of the properties held for sale as of September 30, 2014 were as follows:
	Real estate assets and other assets held for sale	(in thousands)
	Land and improvements	$	18,077
	Buildings and improvements	31,530
	Total real estate held for sale	49,607
	Accumulated depreciation and amortization	(5,046		)
	Total real estate held for sale, net	44,561
	Current receivables, net	56
	Deferred rent receivables, net	1,241
	Deferred leasing costs and acquisition-related intangible assets, net	3,754
	Prepaid expenses and other assets, net	203
	Real estate and other assets held for sale, net	$	49,815
	Liabilities and deferred revenue of real estate assets held for sale
	Accounts payable, accrued expenses and other liabilities	$	944
	Deferred revenue and acquisition-related intangible liabilities, net	1,733
	Rents received in advance and tenant security deposits	422
	Liabilities and deferred revenue of real estate assets held for sale	$	3,099
	Operating Property Dispositions
	The following table summarizes the operating properties sold during the nine months ended September 30, 2014:
	Location		Property Type		Month of Disposition		Number of Buildings		Rentable Square Feet
	San Diego Properties, San Diego, CA (1)		Office		January		12		1,049,035
	9785 & 9791 Towne Centre Drive, San Diego, CA		Office		June		2		126,000
	111 Pacifica, Irvine, CA		Office		September		1		67,496
	Total 2014 Dispositions						15		1,242,531
	________________________
	-1	The San Diego Properties included the following: 10020 Pacific Mesa Boulevard, 6055 Lusk Avenue, 5010 and 5005 Wateridge Vista Drive, 15435 and 15445 Innovation Drive, and 15051, 15073, 15231, 15253, 15333 and 15378 Avenue of Science. These properties were held for sale as of December 31, 2013.
	Discontinued Operations
	Discontinued operations for the three months ended September 30, 2014 includes the income of the property sold in September 2014 and the two properties classified as held for sale at September 30, 2014. For the nine months ended September 30, 2014 and 2013, discontinued operations also included the gains on dispositions of $110.4 million related to the June 2014 office property disposition and income of the twelve operating office properties sold in January 2014. The operations related to the June 2014 office property dispositions were immaterial for classification as discontinued operations. For the three and nine months ended September 30, 2013, discontinued operations also included the income from three operating office properties that were sold during those respective periods in 2013. The following table summarizes the revenue and expense components that comprise income from discontinued operations for the three and nine months ended September 30, 2014 and 2013:
		Three Months Ended September 30,							Nine Months Ended September 30,
		2014				2013			2014		2013
		(in thousands)
	Revenues:
	Rental income	$	1,982			$	8,189		$	6,361	$	23,692
	Tenant reimbursements	70				918			247		2,420
	Other property income	6				5,151			26		5,159
	Total revenues	2,058				14,258			6,634		31,271
	Expenses:
	Property expenses	705				2,673			1,952		5,753
	Real estate taxes	196				891			628		2,626
	Depreciation and amortization	609				4,846			1,963		11,693
	Total expenses	1,510				8,410			4,543		20,072
	Income from discontinued operations before gains on dispositions of discontinued operations	548				5,848			2,091		11,199
	Gains on dispositions of discontinued operations	5,587				—			110,391		423
	Total income from discontinued operations	$	6,135			$	5,848		$	112,482	$	11,622
	Land Disposition
	During the nine months ended September 30, 2014, the Company sold a land parcel located at 10850 Via Frontera in the Rancho Bernardo submarket of San Diego, California for a gross sales price of $33.1 million, resulting in a gain on sale of $3.5 million. The land parcel noted above did not meet the criteria for classification as discontinued operations because the parcel did not have any significant operations prior to disposal. Therefore, the gain on sale is included on our consolidated statements of operations as gain on sale of land within continuing operations.
	Restricted Cash Related to Dispositions
	During the nine months ended September 30, 2014, the net cash proceeds from the office properties disposed of during the period were temporarily being held at qualified intermediaries, at our direction, for the purpose of facilitating Section 1031 Exchanges. During the nine months ended September 30, 2014, we successfully completed four Section 1031 Exchanges and all remaining cash proceeds related to these transactions were released from the qualified intermediaries upon completion.
	As of December 31, 2013, approximately $32.2 million, respectively, of net cash proceeds related to the land and office properties disposed of during the year ended December 31, 2013 were temporarily being held at qualified intermediaries, at our direction, for the purpose of facilitating Section 1031 Exchanges. The cash proceeds are included in restricted cash on the consolidated balance sheet at December 31, 2013. In February 2014, we successfully completed one of the Section 1031 Exchanges and the $32.2 million cash proceeds were released from the qualified intermediary.

Net_Income_Available_to_Common

Net Income Available to Common Stockholders Per Share of the Company	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Net Income (Loss) Available to Common Stockholders Per Share of the Company	'
	Net Income Available to Common Stockholders Per Share of the Company
	The following table reconciles the numerator and denominator in computing the Company’s basic and diluted per-share computations for net income available to common stockholders for the three and nine months ended September 30, 2014 and 2013:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
		(in thousands, except share and per share amounts)
	Numerator:
	Income from continuing operations	$	13,168		$	3,179		$	39,896		$	9,896
	(Income) Loss from continuing operations attributable to noncontrolling common units of the Operating Partnership	(193		)	3			(635		)	2
	Preferred dividends	(3,313		)	(3,312		)	(9,938		)	(9,938		)
	Allocation to participating securities (1)	(432		)	(450		)	(1,285		)	(1,292		)
	Numerator for basic and diluted income from continuing operations available to common stockholders	9,230			(580		)	28,038			(1,332		)
	Income from discontinued operations	6,135			5,848			112,482			11,622
	Income from discontinued operations attributable to noncontrolling common units of the Operating Partnership	(128		)	(134		)	(2,376		)	(268		)
	Numerator for basic and diluted net income available to common stockholders	$	15,237		$	5,134		$	138,144		$	10,022
	Denominator:
	Basic weighted average vested shares outstanding	83,161,323			76,768,893			82,525,033			75,750,822
	Effect of dilutive securities	1,949,133			—			2,097,589			—
	Diluted weighted average vested shares and common share equivalents outstanding	85,110,456			76,768,893			84,622,622			75,750,822
	Basic earnings per share:
	Income (loss) from continuing operations available to common stockholders per share	$	0.11		$	0		$	0.34		$	(0.02	)
	Income from discontinued operations per common share	0.07			0.07			1.33			0.15
	Net income available to common stockholders per share	$	0.18		$	0.07		$	1.67		$	0.13
	Diluted earnings per share:
	Income (loss) from continuing operations available to common stockholders per share	$	0.11		$	0		$	0.33		$	(0.02	)
	Income from discontinued operations per common share	0.07			0.07			1.3			0.15
	Net income available to common stockholders per share	$	0.18		$	0.07		$	1.63		$	0.13
	________________________
	-1	Participating securities include nonvested shares, certain time-based RSUs and vested market measure-based RSUs.
	The impact of the contingently issuable shares, which consist of the 4.25% Exchangeable Notes and stock options, were considered in our diluted earnings per share calculation for the three and nine months ended September 30, 2014 because we reported income from continuing operations attributable to common stockholders in the respective periods and the effect was dilutive. The impact of the contingently issuable shares were not considered in our diluted earnings per share calculation for the three and nine months ended September 30, 2013 because we reported a loss from continuing operations available to common stockholders in the respective periods and the effect was anti-dilutive.
	The 2014 Performance-Based RSUs and our other nonvested market measure-based RSUs are not included in dilutive securities as of September 30, 2014 because they are not included until all the necessary performance conditions have been met. The impact of our nonvested market measure-based RSUs were not included in dilutive securities as of September 30, 2013 because they were not considered contingently issuable shares as not all the necessary performance conditions were met.

Net_Income_Available_to_Common1

Net Income Available to Common Unitholders Per Unit of the Operating Partnership	9 Months Ended
	Sep. 30, 2014
Earnings Per Unit [Abstract]	'
Net Income (Loss) Available to Common Unitholders per Unit of the Operating Partnership	'
	Net Income Available to Common Unitholders Per Unit of the Operating Partnership
	The following table reconciles the numerator and denominator in computing the Operating Partnership’s basic and diluted per-unit computations for net income available to common unitholders for the three and nine months ended September 30, 2014 and 2013:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
		(in thousands, except unit and per unit amounts)
	Numerator:
	Income from continuing operations	$	13,168		$	3,179		$	39,896		$	9,896
	Income from continuing operations attributable to noncontrolling interests in consolidated subsidiaries	(59		)	(47		)	(201		)	(178		)
	Preferred distributions	(3,313		)	(3,312		)	(9,938		)	(9,938		)
	Allocation to participating securities (1)	(432		)	(450		)	(1,285		)	(1,292		)
	Numerator for basic and diluted income from continuing operations available to common unitholders	9,364			(630		)	28,472			(1,512		)
	Income from discontinued operations	6,135			5,848			112,482			11,622
	Numerator for basic and diluted net income available to common unitholders	$	15,499		$	5,218		$	140,954		$	10,110
	Denominator:
	Basic weighted average vested units outstanding	84,965,523			78,590,396			84,329,317			77,574,907
	Effect of dilutive securities	1,949,133			—			2,097,589			—
	Diluted weighted average vested units and common unit equivalents outstanding	86,914,656			78,590,396			86,426,906			77,574,907
	Basic earnings per unit:
	Income (loss) from continuing operations available to common unitholders per unit	$	0.11		$	0		$	0.34		$	(0.02	)
	Income from discontinued operations per common unit	0.07			0.07			1.33			0.15
	Net income available to common unitholders per unit	$	0.18		$	0.07		$	1.67		$	0.13
	Diluted earnings per unit:
	Income (loss) from continuing operations available to common unitholders per unit	$	0.11		$	0		$	0.33		$	(0.02	)
	Income from discontinued operations per common unit	0.07			0.07			1.3			0.15
	Net income available to common unitholders per unit	$	0.18		$	0.07		$	1.63		$	0.13
	________________________
	-1	Participating securities include nonvested shares, certain time-based RSUs and vested market measure-based RSUs.
	The impact of the contingently issuable units, which consist of the 4.25% Exchangeable Notes and stock options, were considered in our diluted earnings per unit calculation for the three and nine months ended September 30, 2014 because the Operating Partnership reported income from continuing operations attributable to common unitholders in the respective periods and the effect was dilutive. The impact of the contingently issuable shares were not considered in our diluted earnings per unit calculation for the three and nine months ended September 30, 2013 because the Operating Partnership reported a loss from continuing operations available to common unitholders in the respective periods and the effect was anti-dilutive.
	The 2014 Performance-Based RSUs and our other nonvested market measure-based RSUs are not included in dilutive securities as of September 30, 2014 because they are not included until all the necessary performance conditions have been met. The impact of our nonvested market measure-based RSUs were not included in dilutive securities as of September 30, 2013 because they were not considered contingently issuable shares as not all the necessary performance conditions were met.

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	In October 2014, the Company completed the acquisition of a 1.9 acre land site in the Central SOMA submarket of San Francisco, California for approximately $27.0 million. The acquisition, which was completed through the execution of a merger transaction, was funded through the issuance of 351,476 shares of the Company’s common stock valued at approximately $21.6 million and the payment of approximately $5.4 million in cash to extinguish existing debt on the undeveloped land.
	In October 2014, the Company issued 217,042 common shares under its at-the-market stock offering program at a weighted average price of $59.38 per share before selling commissions.
	On October 15, 2014, aggregate dividends, distributions and dividend equivalents of $30.3 million were paid to common stockholders and common unitholders of record on September 30, 2014 and RSU holders of record on the payment date.

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Consolidation Policy	'
	The consolidated financial statements of the Company include the consolidated financial position and results of operations of the Company, the Operating Partnership, the Finance Partnership, KSLLC, Redwood City Partners, LLC and all of our wholly owned and controlled subsidiaries. The consolidated financial statements of the Operating Partnership include the consolidated financial position and results of operations of the Operating Partnership, the Finance Partnership, KSLLC, Redwood City Partners, LLC and all wholly-owned and controlled subsidiaries of the Operating Partnership. All intercompany balances and transactions have been eliminated in the consolidated financial statements.
Basis of Accounting	'
	The accompanying interim financial statements have been prepared by management in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and in conjunction with the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures required for annual financial statements have been condensed or excluded pursuant to SEC rules and regulations. Accordingly, the interim financial statements do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, the accompanying interim financial statements reflect all adjustments of a normal and recurring nature that are considered necessary for a fair presentation of the results for the interim periods presented. However, the results of operations for the interim periods are not necessarily indicative of the results that may be expected for the year ending December 31, 2014. The interim financial statements for the Company and the Operating Partnership should be read in conjunction with the audited consolidated financial statements and notes thereto included in our annual report on Form 10-K/A for the year ended December 31, 2013.
	Certain amounts in the consolidated statements of operations for prior periods have been reclassified to reflect the activity of discontinued operations.
Partially Owned Entities and Variable Interest Entities	'
	At September 30, 2014, the consolidated financial statements of the Company and the Operating Partnership included one variable interest entity (“VIE”), in which we were deemed to be the primary beneficiary. The VIE, Redwood City Partners, LLC, was established in the second quarter of 2013 in connection with an undeveloped land acquisition. The impact of consolidating the VIE increased the Company’s total assets, liabilities and noncontrolling interests by approximately $98.5 million (of which $98.1 million related to real estate held for investment on our consolidated balance sheet), approximately $20.1 million and approximately $5.2 million, respectively, as of September 30, 2014. As of December 31, 2013, the consolidated financial statements of the Company and the Operating Partnership included four VIEs, in which we were deemed to be the primary beneficiary. One of the VIEs was Redwood City Partners, LLC and the remaining three VIEs were established during the third and fourth quarter of 2013 to facilitate potential Section 1031 Exchanges. During the three months ended March 31, 2014, the Section 1031 Exchanges were successfully completed and the three VIEs were terminated. As a result, $32.2 million of our restricted cash balance at December 31, 2013, which related to prior period disposition proceeds that were set aside to facilitate the Section 1031 Exchanges, was released from escrow. The impact of consolidating the VIEs increased the Company’s total assets, liabilities and noncontrolling interests by approximately $251.8 million (of which $234.5 million related to real estate held for investment on our consolidated balance sheet), approximately $12.1 million and approximately $4.9 million, respectively, as of December 31, 2013.
Recent Accounting Pronouncements	'
	On June 19, 2014, the Financial Accounting Standards Board (“FASB”) issued their final standard to amend the accounting guidance for stock compensation tied to performance targets (Accounting Standards Update (“ASU”) No. 2014-12). The issue is the result of a consensus of the FASB Emerging Issues Task Force (Issue No. 13-D). The standard requires that a performance target that could be achieved after the requisite service period be treated as a performance condition, and as a result, this type of performance condition may delay expense recognition until achievement of the performance target is probable. The ASU is effective for all entities for reporting periods (including interim periods) beginning after December 15, 2015, and early adoption is permitted. The Company will adopt the guidance effective January 1, 2016 and the guidance is not anticipated to have a material impact on our consolidated financial statements or notes to our consolidated financial statements.
	On May 28, 2014, the FASB issued their final standard on revenue from contracts with customers. The guidance specifically notes that lease contracts with customers are a scope exception. The standard (ASU No. 2014-09) outlines a single comprehensive model for entities to use in accounting for revenues arising from contracts with customers. The ASU is effective for annual reporting periods (including interim periods), beginning after December 15, 2016, and early adoption is not permitted. The Company will adopt the guidance effective January 1, 2017 and is currently assessing the impact on our consolidated financial statements and notes to our consolidated financial statements.
	On April 10, 2014, the FASB issued final guidance to change the criteria for reporting discontinued operations while enhancing disclosures in this area (ASU No. 2014-08). Under the new guidance, only disposals representing a strategic shift, such as a major line of business, a major geographical area or a major equity investment, should be presented as discontinued operations. The guidance will be applied prospectively to new disposals and new classifications of disposal groups as held for sale after the effective date. The guidance is effective for annual financial statements with fiscal years beginning on or after December 15, 2014 with early adoption permitted for disposals or classifications as held for sale which have not been reported in financial statements previously issued or available for issuance. The Company will adopt the guidance effective January 1, 2015 and the guidance is not anticipated to have a material impact on our consolidated financial statements and notes to our consolidated financial statements.

Organization_and_Basis_of_Pres2

Organization and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Summary of real estate properties	'
	Our stabilized portfolio of operating properties was comprised of the following office properties at September 30, 2014:
		Number of		Rentable	Number of	Percentage
		Buildings		Square Feet	Tenants	Occupied
	Stabilized Office Properties	105		13,486,006	526	94.1	%
	As of September 30, 2014, the following properties were excluded from our stabilized portfolio:
		Number of	Estimated Rentable
		Properties/Projects	Square Feet
	Properties Held for Sale (1)	2	228,788
	Development projects under construction (2)(3)	5	2,000,000
	_______________
	-1	Includes two properties, one located in Orange, California and the other in the San Rafael submarket of San Francisco, California. For additional information see Note 13.
	-2	Estimated rentable square feet upon completion.
	-3	During the third quarter of 2014, we stabilized a development property in the Sunnyvale submarket of San Francisco, California consisting of three office buildings encompassing 587,429 square feet. As a result, this project is now included in our stabilized portfolio as of September 30, 2014.

Acquisitions_Tables

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2014
Business Acquisition [Line Items]	'
Schedule of Significant Acquisitions	'
	During the nine months ended September 30, 2014, we acquired one undeveloped land site listed below from an unrelated third party. The acquisition was funded with proceeds from the Company’s at-the-market stock offering program (see Note 7) and disposition proceeds (see Note 13).
	Project		Date of Acquisition	Type	Purchase Price
					(in millions)
	Kilroy Mission Bay, San Francisco, CA (1)		23-May-14	Land	$	95
	_______________
	-1	In connection with this acquisition, we also assumed $2.3 million in accrued liabilities which are not included in the purchase price above. As of September 30, 2014, the purchase price and assumed liabilities are included in undeveloped land and construction in progress and the assumed liabilities are included in accounts payable, accrued expenses and other liabilities on our consolidated balance sheets.
Office Properties Acquisitions [Member]	'
Business Acquisition [Line Items]	'
Acquired operating properties from unrelated third parties	'
	During the nine months ended September 30, 2014, we acquired the one operating office property listed below, from an unrelated third party. The acquisition was funded with proceeds from 2013 and 2014 dispositions (see Note 13).
	Property		Date of Acquisition	Number of	Rentable Square		Occupancy as of September 30, 2014	Purchase
				Buildings	Feet			Price
								(in millions)
	401 Terry Avenue North, Seattle, WA		March 13, 2014	1	140,605		100.00%	$	106.1
Fair values of assets acquired and liabilities assumed	'
	The following table summarizes the estimated fair values of the assets acquired and liabilities assumed on the acquisition date:
		Total 2014
		Acquisitions
		(in thousands)
	Assets
	Land and improvements	$	22,500
	Buildings and improvements (1)	77,046
	Deferred leasing costs and acquisition-related intangible assets (2)	11,199
	Total assets acquired	110,745
	Liabilities
	Deferred revenue and acquisition-related intangible liabilities (3)	4,620
	Total liabilities assumed	4,620
	Net assets and liabilities acquired	$	106,125
	_______________
	-1	Represents buildings, building improvements and tenant improvements.
	-2	Represents in-place leases of approximately $9.3 million (with a weighted average amortization period of seven years) and leasing commissions of approximately $1.9 million (with a weighted average amortization period of seven years) at the time of the acquisition.
	-3	Represents below-market leases of approximately $4.6 million (with a weighted average amortization period of seven years).

Deferred_Leasing_Costs_and_Acq1

Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, net (Tables)	9 Months Ended
	Sep. 30, 2014
Intangible Assets and Liabilities Disclosure [Abstract]	'
Summary of identified deferred leasing costs and acquisition-related intangible assets and liabilities	'
	The following table summarizes our deferred leasing costs and acquisition-related intangible assets (acquired value of leasing costs, above-market operating leases, in-place leases and below-market ground lease obligation) and intangible liabilities (acquired value of below-market operating leases and above-market ground lease obligation) as of September 30, 2014 and December 31, 2013:
		September 30, 2014			December 31, 2013
		(in thousands)
	Deferred Leasing Costs and Acquisition-Related Intangible Assets, net:
	Deferred leasing costs	$	196,963		$	178,720
	Accumulated amortization	(71,911		)	(63,246		)
	Deferred leasing costs, net	125,052			115,474
	Above-market operating leases	21,926			27,635
	Accumulated amortization	(14,151		)	(14,283		)
	Above-market operating leases, net	7,775			13,352
	In-place leases	94,281			100,318
	Accumulated amortization	(44,522		)	(42,999		)
	In-place leases, net	49,759			57,319
	Below-market ground lease obligation	490			490
	Accumulated amortization	(19		)	(13		)
	Below-market ground lease obligation, net	471			477
	Total deferred leasing costs and acquisition-related intangible assets, net	$	183,057		$	186,622
	Acquisition-Related Intangible Liabilities, net: (1)
	Below-market operating leases	$	69,533		$	69,385
	Accumulated amortization	(31,288		)	(25,706		)
	Below-market operating leases, net	38,245			43,679
	Above-market ground lease obligation	6,320			6,320
	Accumulated amortization	(298		)	(223		)
	Above-market ground lease obligation, net	6,022			6,097
	Total acquisition-related intangible liabilities, net	$	44,267		$	49,776
	_______________
	-1	Included in deferred revenue and acquisition-related intangible liabilities, net in the consolidated balance sheets.
Schedule Of Finite Lived Intangible Assets and Liabilities Amortization Expense	'
	The following table sets forth amortization related to deferred leasing costs and acquisition-related intangibles, including amounts attributable to discontinued operations, for the three and nine months ended September 30, 2014 and 2013:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
		(in thousands)
	Deferred leasing costs (1)	$	7,132		$	6,945		$	20,683		$	20,882
	Above-market operating leases (2)	1,305			1,417			4,230			4,214
	In-place leases (1)	5,169			7,677			17,090			22,546
	Below-market ground lease obligation (3)	2			2			6			6
	Below-market operating leases (4)	(2,940		)	(3,355		)	(10,054		)	(10,229		)
	Above-market ground lease obligation (5)	(26		)	(25		)	(76		)	(76		)
	Total	$	10,642		$	12,661		$	31,879		$	37,343
	_______________
	-1	The amortization of deferred leasing costs related to lease incentives is recorded to rental income and other deferred leasing costs and in-place leases is recorded to depreciation and amortization expense in the consolidated statements of operations for the periods presented.
	-2	The amortization of above-market operating leases is recorded as a decrease to rental income in the consolidated statements of operations for the periods presented.
	-3	The amortization of the below-market ground lease obligation is recorded as an increase to ground lease expense in the consolidated statements of operations for the periods presented.
	-4	The amortization of below-market operating leases is recorded as an increase to rental income in the consolidated statements of operations for the periods presented.
	-5	The amortization of the above-market ground lease obligation is recorded as a decrease to ground lease expense in the consolidated statements of operations for the periods presented.
Schedule of Finite Lived Intangible Assets And Liabilities Future Amortization Expense	'
	The following table sets forth the estimated annual amortization expense related to deferred leasing costs and acquisition-related intangibles as of September 30, 2014 for future periods:
	Year	Deferred Leasing Costs			Above-Market Operating Leases (1)			In-Place Leases			Below-Market Ground Lease Obligation (2)			Below-Market Operating Leases (3)			Above-Market Ground Lease Obligation (4)
		(in thousands)
	Remaining 2014	$	6,936		$	993		$	4,274		$	2		$	(2,851	)	$	(26	)
	2015	24,851			2,530			13,131			8			(9,567		)	(101		)
	2016	22,045			1,503			10,080			8			(7,847		)	(101		)
	2017	19,163			1,241			8,440			8			(6,780		)	(101		)
	2018	15,748			831			5,532			8			(5,177		)	(101		)
	Thereafter	36,309			677			8,302			437			(6,023		)	(5,592		)
	Total	$	125,052		$	7,775		$	49,759		$	471		$	(38,245	)	$	(6,022	)
	_______________
	-1	Represents estimated annual amortization related to above-market operating leases. Amounts will be recorded as a decrease to rental income in the consolidated statements of operations.
	-2	Represents estimated annual amortization related to below-market ground lease obligations. Amounts will be recorded as an increase to ground lease expense in the consolidated statements of operations.
	-3	Represents estimated annual amortization related to below-market operating leases. Amounts will be recorded as an increase to rental income in the consolidated statements of operations.
	-4	Represents estimated annual amortization related to above-market ground lease obligations. Amounts will be recorded as a decrease to ground lease expense in the consolidated statements of operations.

Receivables_Tables

Receivables (Tables)	9 Months Ended
	Sep. 30, 2014
Receivables [Abstract]	'
Current Receivables, net	'
	Current receivables, net is primarily comprised of contractual rents and other lease-related obligations due from tenants. The balance consisted of the following as of September 30, 2014 and December 31, 2013:
		September 30, 2014 (1)			December 31, 2013
		(in thousands)
	Current receivables	$	8,626		$	12,866
	Allowance for uncollectible tenant receivables	(2,183		)	(2,123		)
	Current receivables, net	$	6,443		$	10,743
Deferred Rent Receivables, net	'
	Deferred rent receivables, net consisted of the following as of September 30, 2014 and December 31, 2013:
		September 30, 2014 (1)			December 31, 2013
		(in thousands)
	Deferred rent receivables	$	141,899		$	129,198
	Allowance for deferred rent receivables	(1,989		)	(2,075		)
	Deferred rent receivables, net	$	139,910		$	127,123
	______________
	-1	Excludes deferred rent receivables, net related to properties held for sale at September 30, 2014.

Secured_and_Unsecured_Debt_of_1

Secured and Unsecured Debt of the Operating Partnership (Tables) (Kilroy Realty, L.P. [Member])	9 Months Ended
	Sep. 30, 2014
Debt Instrument [Line Items]	'
Schedule of Term Loan Facilities [Table Text Block]	'
	The following table summarizes the balance and terms of our term loan facility as of September 30, 2014 and December 31, 2013:
		September 30, 2014			December 31, 2013
		(in thousands)
	Outstanding borrowings	$	150,000		$	150,000
	Interest rate	1.4		%	1.75		%
	Maturity date	Jul-19			Mar-16
Per Share Average Trading Price Of Companys Common Stock On Stock Exchange [Tables Text Block]	'
	For the three and nine months ended September 30, 2014 and 2013, 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 below:
		Three Months Ended September 30,			Nine Months Ended September 30,
		2014		2013	2014		2013
	Per share average trading price of the Company’s common stock	$62.06		$51.57	$59.27		$52.42
Schedule of Debt Conversions, Fair Value Upon Conversion [Table Text Block]	'
	The 4.25% Exchangeable Notes were exchangeable as of September 30, 2014 and September 30, 2013. If the 4.25% Exchangeable Notes outstanding as of those dates were exchanged, the approximate fair value of the shares upon exchange at September 30, 2014 and 2013, using the per share average trading price presented in the table above, would have been as follows:
		Three Months Ended September 30,							Nine Months Ended September 30,
		2014			2013				2014				2013
		(in thousands)
	Approximate fair value of shares upon exchange	$	229,840		$	245,200			$	223,732			$	248,000
	Principal amount of the 4.25% Exchangeable Notes	135,481			172,500				135,481				172,500
	Approximate fair value in excess amount of principal amount	$	94,359		$	72,700			$	88,251			$	75,500
Interest expense for the exchangeable notes	'
	The following table summarizes the total interest expense attributable to the 4.25% Exchangeable Notes based on the respective effective interest rates, before the effect of capitalized interest, for the three and nine months September 30, 2014 and 2013:
		Three Months Ended September 30,							Nine Months Ended September 30,
		2014			2013				2014				2013
		(in thousands)
	Contractual interest payments	$	1,439		$	1,833			$	4,908			$	5,498
	Amortization of discount	1,004			1,116				3,337				3,291
	Interest expense attributable to the 4.25% Exchangeable Notes	$	2,443		$	2,949			$	8,245			$	8,789
Capped call Transactions	'
	The table below summarizes our capped call option positions for the 4.25% Exchangeable Notes as of September 30, 2014 and December 31, 2013.
		4.25% Exchangeable Notes
		September 30, 2014			December 31, 2013
	Referenced shares of common stock (1)	3,770,531			4,800,796
	Exchange price, including effect of capped calls	$	42.81		$	42.81
	________________________
	-1	The referenced shares of common stock decreased during the nine months ended September 30, 2014 as a result of the settled exchanges of the 4.25% Exchangeable Notes totaling $37.0 million.
Unsecured Revolving Credit Facility	'
	The following table summarizes the balance and terms of our unsecured revolving credit facility as of September 30, 2014 and December 31, 2013:
		September 30, 2014			December 31, 2013
		(in thousands)
	Outstanding borrowings	$	—		$	45,000
	Remaining borrowing capacity	600,000			455,000
	Total borrowing capacity (1)	$	600,000		$	500,000
	Interest rate (2)(3)	—		%	1.62		%
	Facility fee-annual rate (4)	0.25%			0.30%
	Maturity date	Jul-19			Apr-17
	_______________
	-1	We may elect to borrow, subject to bank approval and obtaining commitments for any additional borrowing capacity, up to an additional $300.0 million under an accordion feature under the terms of the unsecured revolving credit facility and term loan facility.
	-2	Our revolving credit facility interest rate was calculated based on an annual rate of LIBOR plus 1.250% as of September 30, 2014.
	-3	Our revolving credit facility interest rate was calculated based on an annual rate of LIBOR plus 1.450% as of December 31, 2013.
	-4	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 September 30, 2014, $6.2 million of deferred financing costs remains to be amortized through the amended maturity date of our unsecured revolving credit facility.
Stated debt maturities and scheduled amortization payments, excluding debt discounts	'
	The following table summarizes the stated debt maturities and scheduled amortization payments, excluding debt discounts and premiums, as of September 30, 2014:
	Year	(in thousands)
	Remaining 2014	$	138,009
	2015	395,104
	2016	99,431
	2017	71,748
	2018	451,728
	Thereafter	1,268,013
	Total (1)	$	2,424,033
	________________________
	-1	Includes gross principal balance of outstanding debt before impact of net unamortized premiums totaling approximately $4.9 million
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 three and nine months ended September 30, 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.
		Three Months Ended September 30,							Nine Months Ended September 30,
		2014			2013				2014				2013
		(in thousands)
	Gross interest expense	$	29,936		$	27,942			$	85,740			$	83,322
	Capitalized interest and loan fees	(13,328		)	(9,089		)		(35,860		)		(25,301		)
	Interest expense	$	16,608		$	18,853			$	49,880			$	58,021
Secured Debt [Member]	'
Debt Instrument [Line Items]	'
Balance and significant terms of debt	'
	The following table sets forth the composition of our secured debt as of September 30, 2014 and December 31, 2013:
	Type of Debt	Annual Stated Interest Rate (1)		GAAP	Maturity Date		September 30, 2014 (3)				December 31, 2013 (3)
				Effective Rate (1)(2)
							(in thousands)
	Mortgage note payable	4.27%		4.27%	Feb-18		$	131,363			$	133,117
	Mortgage note payable (4)	4.48%		4.48%	Jul-27		97,000				97,000
	Mortgage note payable (4)	6.05%		3.50%	Jun-19		90,065				92,502
	Mortgage note payable	6.51%		6.51%	Feb-17		66,907				67,663
	Mortgage note payable (4)	5.23%		3.50%	Jan-16		53,243				54,570
	Mortgage note payable (4)	5.57%		3.25%	Feb-16		40,611				41,654
	Mortgage note payable (4)	5.09%		3.50%	Aug-15		34,446				34,845
	Mortgage note payable (4)	4.94%		4.00%	Apr-15		26,629				27,641
	Mortgage note payable	7.15%		7.15%	May-17		7,185				8,972
	Other	Various		Various	Various		2,447				2,470
	Total						$	549,896			$	560,434
	______________
	-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 and discounts for the periods presented.
	-4	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.
Exchangeable Debt [Member]	'
Debt Instrument [Line Items]	'
Balance and significant terms of debt	'
	The table below summarizes the balance and significant terms of the Company’s 4.25% Exchangeable Notes due November 2014 (the “4.25% Exchangeable Notes”) outstanding as of September 30, 2014 and December 31, 2013.
		4.25% Exchangeable Notes
		September 30,			December 31,
		2014			2013
		(in thousands)
	Principal amount	$	135,481		$	172,500
	Unamortized discount	(432		)	(4,128		)
	Net carrying amount of liability component	$	135,049		$	168,372
	Carrying amount of equity component (1)	$15,578			$19,835
	Issuance date	Nov-09
	Maturity date	Nov-14
	Stated coupon rate (2)	4.25%
	Effective interest rate (3)	7.13%
	Exchange rate per $1,000 principal value of the 4.25% Exchangeable Notes, as adjusted (3)	27.8307
	Exchange price, as adjusted (4)	$35.93
	Number of shares on which the aggregate consideration to be delivered on conversion is determined (4)	3,770,531			4,800,796
	_______________
	-1	The $15.6 million carrying amount of the equity component at September 30, 2014 represents the proportionate amount of the initial $19.8 million carrying value of the equity component allocated to the remaining $135.5 million outstanding principal balance of the 4.25% Exchangeable Notes at September 30, 2014.
	-2	Interest on the 4.25% Exchangeable Notes is payable semi-annually in arrears on May 15th and November 15th of each year.
	-3	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.
	-4	The exchange rate, exchange price and the number of shares to be delivered upon conversion are subject to adjustment under certain circumstances including increases in our common dividends.
Senior Notes [Member]	'
Debt Instrument [Line Items]	'
Balance and significant terms of debt	'
	The following table summarizes the balance and significant terms of the registered unsecured senior notes issued by the Operating Partnership as of September 30, 2014 and December 31, 2013:
									Principal Amount as of
		Issuance date		Maturity date	Stated		Effective interest rate (1)		September 30,				December 31,
					coupon rate				2014				2013
									(in thousands)
	4.250% Unsecured Senior Notes (2)	Jul-14		Aug-29	4.25%		4.35%		$	400,000			$	—
	Unamortized discount								(4,422		)		—
	Net carrying amount								$	395,578			$	—
	3.800% Unsecured Senior Notes (3)	Jan-13		Jan-23	3.80%		3.80%		$	300,000			$	300,000
	Unamortized discount								(82		)		(90		)
	Net carrying amount								$	299,918			$	299,910
	4.800% Unsecured Senior Notes (4)	Jul-11		Jul-18	4.80%		4.83%		$	325,000			$	325,000
	Unamortized discount								(283		)		(339		)
	Net carrying amount								$	324,717			$	324,661
	6.625% Unsecured Senior Notes (5)	May-10		Jun-20	6.63%		6.74%		$	250,000			$	250,000
	Unamortized discount								(1,207		)		(1,367		)
	Net carrying amount								$	248,793			$	248,633
	5.000% Unsecured Senior Notes (6)	Nov-10		Nov-15	5.00%		5.01%		$	325,000			$	325,000
	Unamortized discount								(44		)		(73		)
	Net carrying amount								$	324,956			$	324,927
	________________________
	-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 the 4.250% unsecured senior notes is payable semi-annually in arrears on February 15th and August 15th of each year.
	-3	Interest on the 3.800% unsecured senior notes is payable semi-annually in arrears on January 15th and July 15th of each year.
	-4	Interest on the 4.800% unsecured senior notes is payable semi-annually in arrears on January 15th and July 15th of each year.
	-5	Interest on the 6.625% unsecured senior notes is payable semi-annually in arrears on June 1st and December 1st of each year.
	-6	Interest on the 5.000% unsecured senior notes is payable semi-annually in arrears on May 3rd and November 3rd of each year.

Stockholders_Equity_of_the_Com1

Stockholders' Equity of the Company (Tables)	9 Months Ended
	Sep. 30, 2014
Class of Stock [Line Items]	'
Schedule of Stockholders Equity [Table Text Block]	'
	The following table sets forth information regarding sales of our common stock under our at-the-market offering program for the nine months ended September 30, 2014:
		Nine months
		ended September 30, 2014
		(in millions, except share
		and per share data)
	Shares of common stock sold during the year	370,700
	Weighted average price per common share	$	61.01
	Aggregate gross proceeds	$	22.6
	Aggregate net proceeds after sales agent compensation	$	22.3

Partners_Capital_of_the_Operat1

Partners' Capital of the Operating Partnership Ownership Interest (Tables)	9 Months Ended
	Sep. 30, 2014
Noncontrolling Interest [Abstract]	'
Redeemable Noncontrolling Interest	'
	The following table sets forth the number of common units held by the Company and the number of common units held by non-affiliate investors and certain of our executive officers and directors in the form of noncontrolling common units as well as the ownership interest held on each respective date:
		September 30, 2014		December 31, 2013		September 30, 2013
	Company owned common units in the Operating Partnership	83,388,220		82,153,944		82,113,491
	Company owned general partnership interest	97.9	%	97.8	%	97.8	%
	Noncontrolling common units of the Operating Partnership	1,804,200		1,805,200		1,821,503
	Ownership interest of noncontrolling interest	2.1	%	2.2	%	2.2	%

ShareBased_Compensation_ShareB

Share-Based Compensation Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of Share-based Payment Award, Restricted Stock Units, Valuation Assumptions	'
	The following table summarizes the assumptions utilized in the Monte Carlo simulation pricing model:
		Fair Value Assumptions
	Fair value per share at May 22, 2014	$65.03
	Expected share price volatility	24.00%
	Risk-free interest rate	0.61%
	Remaining expected life	2.6

Fair_Value_Measurements_and_Di1

Fair Value Measurements and Disclosures (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair value of the company's marketable securities	'
	The following table sets forth the fair value of our marketable securities as of September 30, 2014 and December 31, 2013:
		Fair Value (Level  1) (1)
		September 30, 2014			December 31, 2013
	Description	(in thousands)
	Marketable securities (2)	$	12,076		$	10,008
	_______________
	-1	Based on quoted prices in active markets for identical securities.
	-2	The marketable securities are held in a limited rabbi trust.
Fair value adjustment of marketable securities and deferred compensation plan liability	'
	The following table sets forth the net gain (loss) on marketable securities recorded during the three and nine months ended September 30, 2014 and 2013:
		Three Months Ended September 30,					Nine Months Ended September 30,
		2014			2013		2014		2013
	Description	(in thousands)
	Net (loss) gain on marketable securities	$	(39	)	$	669	$	507	$	995
Carrying value and fair value of company's remaining financial assets and liabilities	'
	The following table sets forth the carrying value and the fair value of our other financial instruments as of September 30, 2014 and December 31, 2013:
		September 30, 2014					December 31, 2013
		Carrying			Fair		Carrying		Fair
		Value			Value		Value		Value
		(in thousands)
	Liabilities
	Secured debt (1)	$	549,896		$	557,217	$	560,434	$	568,760
	Exchangeable senior notes, net (1)	135,049			135,770		168,372		178,190
	Unsecured debt, net (2)	1,743,962			1,825,725		1,431,132		1,523,052
	Unsecured line of credit (1)	—			—		45,000		45,012
	_______________
	-1	Fair value calculated using Level II inputs, which are based on model-derived valuations in which significant inputs and significant value drivers are observable in active markets.
	-2	Fair value calculated using Level I and Level II inputs. Level I inputs are based on quoted prices for identical instruments in active markets. The carrying value and fair value of the Level I instruments was $1,269.2 million and $1,325.0 million, respectively, as of September 30, 2014. The carrying value and fair value of the Level I instruments as of December 31, 2013, was $873.5 million and $929.3 million, respectively. The carrying value and fair value of the Level II instruments was $474.7 million and $500.6 million, respectively, as of September 30, 2014. The carrying value and fair value of the Level II instruments as of December 31, 2013, was $557.7 million and $593.7 million, respectively.

Discontinued_Operations_Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2014
Long Lived Assets Held-for-sale [Line Items]	'
Disclosure of Long Lived Assets Held-for-sale [Table Text Block]	'
	As of September 30, 2014, the following properties were classified as held for sale:
	Location		City/Submarket		Property Type		Number of Buildings	Rentable Square Feet
								(unaudited)
	4040 Civic Center Dr, San Rafael, CA		San Rafael		Office		1	130,237
	999 Town & Country Rd, Orange, CA		Orange		Office		1	98,551
	Total properties held for sale						2	228,788
	The major classes of assets and liabilities of the properties held for sale as of September 30, 2014 were as follows:
	Real estate assets and other assets held for sale	(in thousands)
	Land and improvements	$	18,077
	Buildings and improvements	31,530
	Total real estate held for sale	49,607
	Accumulated depreciation and amortization	(5,046		)
	Total real estate held for sale, net	44,561
	Current receivables, net	56
	Deferred rent receivables, net	1,241
	Deferred leasing costs and acquisition-related intangible assets, net	3,754
	Prepaid expenses and other assets, net	203
	Real estate and other assets held for sale, net	$	49,815
	Liabilities and deferred revenue of real estate assets held for sale
	Accounts payable, accrued expenses and other liabilities	$	944
	Deferred revenue and acquisition-related intangible liabilities, net	1,733
	Rents received in advance and tenant security deposits	422
	Liabilities and deferred revenue of real estate assets held for sale	$	3,099
Property Sold During The Period	'
	The following table summarizes the operating properties sold during the nine months ended September 30, 2014:
	Location		Property Type		Month of Disposition		Number of Buildings		Rentable Square Feet
	San Diego Properties, San Diego, CA (1)		Office		January		12		1,049,035
	9785 & 9791 Towne Centre Drive, San Diego, CA		Office		June		2		126,000
	111 Pacifica, Irvine, CA		Office		September		1		67,496
	Total 2014 Dispositions						15		1,242,531
	________________________
	-1	The San Diego Properties included the following: 10020 Pacific Mesa Boulevard, 6055 Lusk Avenue, 5010 and 5005 Wateridge Vista Drive, 15435 and 15445 Innovation Drive, and 15051, 15073, 15231, 15253, 15333 and 15378 Avenue of Science. These properties were held for sale as of December 31, 2013.
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures	'
	The following table summarizes the revenue and expense components that comprise income from discontinued operations for the three and nine months ended September 30, 2014 and 2013:
		Three Months Ended September 30,							Nine Months Ended September 30,
		2014				2013			2014		2013
		(in thousands)
	Revenues:
	Rental income	$	1,982			$	8,189		$	6,361	$	23,692
	Tenant reimbursements	70				918			247		2,420
	Other property income	6				5,151			26		5,159
	Total revenues	2,058				14,258			6,634		31,271
	Expenses:
	Property expenses	705				2,673			1,952		5,753
	Real estate taxes	196				891			628		2,626
	Depreciation and amortization	609				4,846			1,963		11,693
	Total expenses	1,510				8,410			4,543		20,072
	Income from discontinued operations before gains on dispositions of discontinued operations	548				5,848			2,091		11,199
	Gains on dispositions of discontinued operations	5,587				—			110,391		423
	Total income from discontinued operations	$	6,135			$	5,848		$	112,482	$	11,622

Net_Income_Available_to_Common2

Net Income Available to Common Stockholders Per Share of the Company (Tables)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Net income (loss) available to common stockholders	'
	The following table reconciles the numerator and denominator in computing the Company’s basic and diluted per-share computations for net income available to common stockholders for the three and nine months ended September 30, 2014 and 2013:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
		(in thousands, except share and per share amounts)
	Numerator:
	Income from continuing operations	$	13,168		$	3,179		$	39,896		$	9,896
	(Income) Loss from continuing operations attributable to noncontrolling common units of the Operating Partnership	(193		)	3			(635		)	2
	Preferred dividends	(3,313		)	(3,312		)	(9,938		)	(9,938		)
	Allocation to participating securities (1)	(432		)	(450		)	(1,285		)	(1,292		)
	Numerator for basic and diluted income from continuing operations available to common stockholders	9,230			(580		)	28,038			(1,332		)
	Income from discontinued operations	6,135			5,848			112,482			11,622
	Income from discontinued operations attributable to noncontrolling common units of the Operating Partnership	(128		)	(134		)	(2,376		)	(268		)
	Numerator for basic and diluted net income available to common stockholders	$	15,237		$	5,134		$	138,144		$	10,022
	Denominator:
	Basic weighted average vested shares outstanding	83,161,323			76,768,893			82,525,033			75,750,822
	Effect of dilutive securities	1,949,133			—			2,097,589			—
	Diluted weighted average vested shares and common share equivalents outstanding	85,110,456			76,768,893			84,622,622			75,750,822
	Basic earnings per share:
	Income (loss) from continuing operations available to common stockholders per share	$	0.11		$	0		$	0.34		$	(0.02	)
	Income from discontinued operations per common share	0.07			0.07			1.33			0.15
	Net income available to common stockholders per share	$	0.18		$	0.07		$	1.67		$	0.13
	Diluted earnings per share:
	Income (loss) from continuing operations available to common stockholders per share	$	0.11		$	0		$	0.33		$	(0.02	)
	Income from discontinued operations per common share	0.07			0.07			1.3			0.15
	Net income available to common stockholders per share	$	0.18		$	0.07		$	1.63		$	0.13
	________________________
	-1	Participating securities include nonvested shares, certain time-based RSUs and vested market measure-based RSUs.

Net_Income_Available_to_Common3

Net Income Available to Common Unitholders Per Unit of the Operating Partnership (Tables)	9 Months Ended
	Sep. 30, 2014
Net Income Available To Common Unitholders [Line Items]	'
Net income (loss) available to common unitholders	'
	The following table reconciles the numerator and denominator in computing the Company’s basic and diluted per-share computations for net income available to common stockholders for the three and nine months ended September 30, 2014 and 2013:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
		(in thousands, except share and per share amounts)
	Numerator:
	Income from continuing operations	$	13,168		$	3,179		$	39,896		$	9,896
	(Income) Loss from continuing operations attributable to noncontrolling common units of the Operating Partnership	(193		)	3			(635		)	2
	Preferred dividends	(3,313		)	(3,312		)	(9,938		)	(9,938		)
	Allocation to participating securities (1)	(432		)	(450		)	(1,285		)	(1,292		)
	Numerator for basic and diluted income from continuing operations available to common stockholders	9,230			(580		)	28,038			(1,332		)
	Income from discontinued operations	6,135			5,848			112,482			11,622
	Income from discontinued operations attributable to noncontrolling common units of the Operating Partnership	(128		)	(134		)	(2,376		)	(268		)
	Numerator for basic and diluted net income available to common stockholders	$	15,237		$	5,134		$	138,144		$	10,022
	Denominator:
	Basic weighted average vested shares outstanding	83,161,323			76,768,893			82,525,033			75,750,822
	Effect of dilutive securities	1,949,133			—			2,097,589			—
	Diluted weighted average vested shares and common share equivalents outstanding	85,110,456			76,768,893			84,622,622			75,750,822
	Basic earnings per share:
	Income (loss) from continuing operations available to common stockholders per share	$	0.11		$	0		$	0.34		$	(0.02	)
	Income from discontinued operations per common share	0.07			0.07			1.33			0.15
	Net income available to common stockholders per share	$	0.18		$	0.07		$	1.67		$	0.13
	Diluted earnings per share:
	Income (loss) from continuing operations available to common stockholders per share	$	0.11		$	0		$	0.33		$	(0.02	)
	Income from discontinued operations per common share	0.07			0.07			1.3			0.15
	Net income available to common stockholders per share	$	0.18		$	0.07		$	1.63		$	0.13
	________________________
	-1	Participating securities include nonvested shares, certain time-based RSUs and vested market measure-based RSUs.
Kilroy Realty, L.P. [Member]	'
Net Income Available To Common Unitholders [Line Items]	'
Net income (loss) available to common unitholders	'
	The following table reconciles the numerator and denominator in computing the Operating Partnership’s basic and diluted per-unit computations for net income available to common unitholders for the three and nine months ended September 30, 2014 and 2013:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
		(in thousands, except unit and per unit amounts)
	Numerator:
	Income from continuing operations	$	13,168		$	3,179		$	39,896		$	9,896
	Income from continuing operations attributable to noncontrolling interests in consolidated subsidiaries	(59		)	(47		)	(201		)	(178		)
	Preferred distributions	(3,313		)	(3,312		)	(9,938		)	(9,938		)
	Allocation to participating securities (1)	(432		)	(450		)	(1,285		)	(1,292		)
	Numerator for basic and diluted income from continuing operations available to common unitholders	9,364			(630		)	28,472			(1,512		)
	Income from discontinued operations	6,135			5,848			112,482			11,622
	Numerator for basic and diluted net income available to common unitholders	$	15,499		$	5,218		$	140,954		$	10,110
	Denominator:
	Basic weighted average vested units outstanding	84,965,523			78,590,396			84,329,317			77,574,907
	Effect of dilutive securities	1,949,133			—			2,097,589			—
	Diluted weighted average vested units and common unit equivalents outstanding	86,914,656			78,590,396			86,426,906			77,574,907
	Basic earnings per unit:
	Income (loss) from continuing operations available to common unitholders per unit	$	0.11		$	0		$	0.34		$	(0.02	)
	Income from discontinued operations per common unit	0.07			0.07			1.33			0.15
	Net income available to common unitholders per unit	$	0.18		$	0.07		$	1.67		$	0.13
	Diluted earnings per unit:
	Income (loss) from continuing operations available to common unitholders per unit	$	0.11		$	0		$	0.33		$	(0.02	)
	Income from discontinued operations per common unit	0.07			0.07			1.3			0.15
	Net income available to common unitholders per unit	$	0.18		$	0.07		$	1.63		$	0.13
	________________________
	-1	Participating securities include nonvested shares, certain time-based RSUs and vested market measure-based RSUs.

Organization_and_Basis_of_Pres3

Organization and Basis of Presentation (Details)	9 Months Ended
	Sep. 30, 2014
Real Estate Properties [Line Items]	'
Rentable square feet	79,000
Kilroy Realty Finance, Inc. [Member]	'
Real Estate Properties [Line Items]	'
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	1.00%
Properties Held for Sale [Member]	'
Real Estate Properties [Line Items]	'
Number of buildings	2	[1]
Rentable square feet	228,788	[1]
Development Properties [Member]	'
Real Estate Properties [Line Items]	'
Number of buildings	5	[2],[3]
Rentable square feet	2,000,000	[2],[3]
Office Properties [Member]	'
Real Estate Properties [Line Items]	'
Number of buildings	105
Rentable square feet	13,486,006
Number of Tenants	526
Percentage Occupied	94.10%
WASHINGTON	'
Real Estate Properties [Line Items]	'
Number of buildings	13
N. Mathilda Avenue 599 and 555, Sunnyvale, CA [Member]	'
Real Estate Properties [Line Items]	'
Number of buildings	3
Rentable square feet	587,429
[1]	Includes two properties, one located in Orange, California and the other in the San Rafael submarket of San Francisco, California.
[2]	During the third quarter of 2014, we stabilized a development property in the Sunnyvale submarket of San Francisco, California consisting of three office buildings encompassing 587,429 square feet. As a result, this project is now included in our stabilized portfolio as of September 30, 2014.
[3]	Estimated rentable square feet upon completion.

Organization_and_Basis_of_Pres4

Organization and Basis of Presentation (Details Textuals) (USD $)	9 Months Ended				9 Months Ended					12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2013
				WASHINGTON	Kilroy Realty, L.P. [Member]	Kilroy Realty, L.P. [Member]	Kilroy Realty Finance, Inc. [Member]	Real Estate Investment [Member]	Real Estate Investment [Member]	Restricted cash [Member]
				building
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'	'	'	'	'	'	'	'
Lease-Up Properties, Maximum Stabilized Occupacy, Percentage	95.00%	'	'	'	'	'	'	'	'	'
Number of buildings	'	'	'	13	'	'	'	'	'	'
Percentage of general partnership interest owned by the company in the Operating Partnership	97.90%	97.80%	97.80%	'	'	'	'	'	'	'
Percentage of Common limited partnership interest owned by certain non-affiliated investors and certain directors and officers of the Company in the Operating Partnership	2.10%	2.20%	2.20%	'	'	'	'	'	'	'
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	'	'	'	'	'	'	1.00%	'	'	'
Percentage of limited partnership interest owned by Operating Partnership	'	'	'	'	99.00%	'	'	'	'	'
Variable Interest Entity, Consolidated, Carrying Amount, Assets	$98,500,000	'	$251,800,000	'	'	'	'	$98,100,000	$234,500,000	'
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	20,100,000	'	12,100,000	'	'	'	'	'	'	'
Noncontrolling Interest in Variable Interest Entity	5,222,000	'	4,885,000	'	'	'	'	'	'	'
Proceeds from Sale of Real Estate Held-for-investment	$368,381,000	$14,409,000	'	'	$368,381,000	$14,409,000	'	'	'	$32,200,000

Acquisitions_Details

Acquisitions (Details) (USD $)	9 Months Ended
	Sep. 30, 2014		Dec. 31, 2013
	sqft
Business Acquisition [Line Items]	'		'
Below Market Lease, Acquired	$4,600,000		'
Business Acquisition, Date of Acquisition Agreement	13-Mar-14		'
Rentable square feet	79,000		'
Liabilities	'		'
Acquired Finite-lived Intangible Liabilities, Weighted Average Useful Life	'7 years		'
Accounts Payable and Accrued Liabilities	243,602,000		198,467,000
Kilroy Mission Bay [Member]	'		'
Business Acquisition [Line Items]	'		'
Payments to Acquire Land	95,000,000	[1]	'
Liabilities	'		'
Accounts Payable and Accrued Liabilities	2,300,000		'
401 Terry Avenue North, Seattle, WA [Member]	'		'
Business Acquisition [Line Items]	'		'
Number of buildings	1		'
Rentable square feet	140,605		'
Occupancy as of September 30, 2014	100.00%		'
Purchase price	106,100,000		'
Office Properties Acquisitions [Member]	'		'
Business Acquisition [Line Items]	'		'
Number of buildings	1		'
Assets	'		'
Land and improvements	22,500,000		'
Buildings and improvements	77,046,000	[2]	'
Deferred leasing costs and acquisition-related intangible assets	11,199,000	[3]	'
Total assets acquired	110,745,000		'
Liabilities	'		'
Deferred revenue and acquisition-related intangible liabilities	4,620,000	[4]	'
Total liabilities assumed	4,620,000		'
Net assets and liabilities acquired	106,125,000		'
In-Place Leases [Member]	'		'
Assets	'		'
Deferred leasing costs and acquisition-related intangible assets	9,300,000		'
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	'7 years		'
Deferred Leasing Costs [Member]	'		'
Assets	'		'
Deferred leasing costs and acquisition-related intangible assets	$1,900,000		'
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	'7 years		'
[1]	In connection with this acquisition, we also assumed $2.3 million in accrued liabilities which are not included in the purchase price above. As of September 30, 2014, the purchase price and assumed liabilities are included in undeveloped land and construction in progress and the assumed liabilities are included in accounts payable, accrued expenses and other liabilities on our consolidated balance sheets.
[2]	Represents buildings, building improvements and tenant improvements.
[3]	Represents in-place leases of approximately $9.3 million (with a weighted average amortization period of seven years) and leasing commissions of approximately $1.9 million (with a weighted average amortization period of seven years) at the time of the acquisition.
[4]	Represents below-market leases of approximately $4.6 million (with a weighted average amortization period of seven years).

Deferred_Leasing_Costs_and_Acq2

Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, net (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Leasing Costs and Acquisition-related Intangible Assets, Net	'		'
Total deferred leasing costs and acquisition-related intangible assets, net	$183,057		$186,622
Acquisition-related Intangible Liabilities, Net	'		'
Total acquisitions-related intangible liabilities, net	44,267	[1]	49,776	[1]
Deferred Leasing Costs [Member]	'		'
Deferred Leasing Costs and Acquisition-related Intangible Assets, Net	'		'
Finite-lived intangible assets, gross	196,963		178,720
Finite-lived intangible assets accumulated amortization	-71,911		-63,246
Finite-lived intangible assets, net	125,052		115,474
Above-Market Leases [Member]	'		'
Deferred Leasing Costs and Acquisition-related Intangible Assets, Net	'		'
Finite-lived intangible assets, gross	21,926		27,635
Finite-lived intangible assets accumulated amortization	-14,151		-14,283
Finite-lived intangible assets, net	7,775	[2]	13,352
In-Place Leases [Member]	'		'
Deferred Leasing Costs and Acquisition-related Intangible Assets, Net	'		'
Finite-lived intangible assets, gross	94,281		100,318
Finite-lived intangible assets accumulated amortization	-44,522		-42,999
Finite-lived intangible assets, net	49,759		57,319
Below Market Ground Lease Obligation [Member]	'		'
Deferred Leasing Costs and Acquisition-related Intangible Assets, Net	'		'
Finite-lived intangible assets, gross	490		490
Finite-lived intangible assets accumulated amortization	-19		-13
Finite-lived intangible assets, net	471	[3]	477
Below Market Lease [Member]	'		'
Acquisition-related Intangible Liabilities, Net	'		'
FiniteLivedIntangibleLiabilitiesGross	69,533		69,385
Accumulated amortization	-31,288		-25,706
Acquisition-related Intangible Liabilities, net	38,245	[4]	43,679
Above-Market Ground Lease Obligation [Member]	'		'
Acquisition-related Intangible Liabilities, Net	'		'
FiniteLivedIntangibleLiabilitiesGross	6,320		6,320
Accumulated amortization	-298		-223
Acquisition-related Intangible Liabilities, net	$6,022	[5]	$6,097
[1]	Included in deferred revenue and acquisition-related intangible liabilities, net in the consolidated balance sheets.
[2]	Represents estimated annual amortization related to above-market operating leases. Amounts will be recorded as a decrease to rental income in the consolidated statements of operations.
[3]	Represents estimated annual amortization related to below-market ground lease obligations. Amounts will be recorded as an increase to ground lease expense in the consolidated statements of operations.
[4]	Represents estimated annual amortization related to below-market operating leases. Amounts will be recorded as an increase to rental income in the consolidated statements of operations.
[5]	Represents estimated annual amortization related to above-market ground lease obligations. Amounts will be recorded as a decrease to ground lease expense in the consolidated statements of operations.

Deferred_Leasing_Costs_and_Acq3

Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, net (Details 1) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Dec. 31, 2013
Amortization for the period related to deferred leasing costs and acquisition-related intangibles	'		'		'		'		'
Amortization Of Intangible Liabilities	($10,642)		($12,661)		($31,879)		($37,343)		'
Deferred Leasing Costs [Member]	'		'		'		'		'
Amortization for the period related to deferred leasing costs and acquisition-related intangibles	'		'		'		'		'
Amortization of Intangible Assets	7,132	[1]	6,945	[1]	20,683	[1]	20,882	[1]	'
Estimated annual amortization related to acquisition-related intangibles	'		'		'		'		'
Remaining 2014	6,936		'		6,936		'		'
2015	24,851		'		24,851		'		'
2016	22,045		'		22,045		'		'
2017	19,163		'		19,163		'		'
2018	15,748		'		15,748		'		'
Thereafter	36,309		'		36,309		'		'
Finite-lived intangible assets, net	125,052		'		125,052		'		115,474
Above-Market Leases [Member]	'		'		'		'		'
Amortization for the period related to deferred leasing costs and acquisition-related intangibles	'		'		'		'		'
Amortization of Intangible Assets	1,305	[2]	1,417	[2]	4,230	[2]	4,214	[2]	'
Estimated annual amortization related to acquisition-related intangibles	'		'		'		'		'
Remaining 2014	993	[3]	'		993	[3]	'		'
2015	2,530	[3]	'		2,530	[3]	'		'
2016	1,503	[3]	'		1,503	[3]	'		'
2017	1,241	[3]	'		1,241	[3]	'		'
2018	831	[3]	'		831	[3]	'		'
Thereafter	677	[3]	'		677	[3]	'		'
Finite-lived intangible assets, net	7,775	[3]	'		7,775	[3]	'		13,352
In-Place Leases [Member]	'		'		'		'		'
Amortization for the period related to deferred leasing costs and acquisition-related intangibles	'		'		'		'		'
Amortization of Intangible Assets	5,169	[1]	7,677	[1]	17,090	[1]	22,546	[1]	'
Estimated annual amortization related to acquisition-related intangibles	'		'		'		'		'
Remaining 2014	4,274		'		4,274		'		'
2015	13,131		'		13,131		'		'
2016	10,080		'		10,080		'		'
2017	8,440		'		8,440		'		'
2018	5,532		'		5,532		'		'
Thereafter	8,302		'		8,302		'		'
Finite-lived intangible assets, net	49,759		'		49,759		'		57,319
Below Market Ground Lease Obligation [Member]	'		'		'		'		'
Amortization for the period related to deferred leasing costs and acquisition-related intangibles	'		'		'		'		'
Amortization of Intangible Assets	2	[4]	2	[4]	6	[4]	6	[4]	'
Estimated annual amortization related to acquisition-related intangibles	'		'		'		'		'
Remaining 2014	2	[5]	'		2	[5]	'		'
2015	8	[5]	'		8	[5]	'		'
2016	8	[5]	'		8	[5]	'		'
2017	8	[5]	'		8	[5]	'		'
2018	8	[5]	'		8	[5]	'		'
Thereafter	437	[5]	'		437	[5]	'		'
Finite-lived intangible assets, net	471	[5]	'		471	[5]	'		477
Below Market Leases [Member]	'		'		'		'		'
Amortization for the period related to deferred leasing costs and acquisition-related intangibles	'		'		'		'		'
Amortization Of Intangible Liabilities	-2,940	[6]	-3,355	[6]	-10,054	[6]	-10,229	[6]	'
Estimated annual amortization related to acquisition-related intangibles	'		'		'		'		'
Remaining 2014	-2,851	[7]	'		-2,851	[7]	'		'
2015	-9,567	[7]	'		-9,567	[7]	'		'
2016	-7,847	[7]	'		-7,847	[7]	'		'
2017	-6,780	[7]	'		-6,780	[7]	'		'
2018	-5,177	[7]	'		-5,177	[7]	'		'
Thereafter	-6,023	[7]	'		-6,023	[7]	'		'
Acquisition-related Intangible Liabilities, net	-38,245	[7]	'		-38,245	[7]	'		-43,679
Above-Market Ground Lease Obligation [Member]	'		'		'		'		'
Amortization for the period related to deferred leasing costs and acquisition-related intangibles	'		'		'		'		'
Amortization Of Intangible Liabilities	-26	[8]	-25	[8]	-76	[8]	-76	[8]	'
Estimated annual amortization related to acquisition-related intangibles	'		'		'		'		'
Remaining 2014	-26	[9]	'		-26	[9]	'		'
2015	-101	[9]	'		-101	[9]	'		'
2016	-101	[9]	'		-101	[9]	'		'
2017	-101	[9]	'		-101	[9]	'		'
2018	-101	[9]	'		-101	[9]	'		'
Thereafter	-5,592	[9]	'		-5,592	[9]	'		'
Acquisition-related Intangible Liabilities, net	($6,022)	[9]	'		($6,022)	[9]	'		($6,097)
[1]	The amortization of deferred leasing costs related to lease incentives is recorded to rental income and other deferred leasing costs and in-place leases is recorded to depreciation and amortization expense in the consolidated statements of operations for the periods presented.
[2]	The amortization of above-market operating leases is recorded as a decrease to rental income in the consolidated statements of operations for the periods presented.
[3]	Represents estimated annual amortization related to above-market operating leases. Amounts will be recorded as a decrease to rental income in the consolidated statements of operations.
[4]	The amortization of the below-market ground lease obligation is recorded as an increase to ground lease expense in the consolidated statements of operations for the periods presented.
[5]	Represents estimated annual amortization related to below-market ground lease obligations. Amounts will be recorded as an increase to ground lease expense in the consolidated statements of operations.
[6]	The amortization of below-market operating leases is recorded as an increase to rental income in the consolidated statements of operations for the periods presented.
[7]	Represents estimated annual amortization related to below-market operating leases. Amounts will be recorded as an increase to rental income in the consolidated statements of operations.
[8]	The amortization of the above-market ground lease obligation is recorded as a decrease to ground lease expense in the consolidated statements of operations for the periods presented.
[9]	Represents estimated annual amortization related to above-market ground lease obligations. Amounts will be recorded as a decrease to ground lease expense in the consolidated statements of operations.

Receivables_Details

Receivables (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Current Receivables, net	'		'
Current receivables	$8,626	[1]	$12,866
Allowance for uncollectible tenant receivables	-2,183	[1]	-2,123
Current receivables, net	6,443	[1]	10,743
Deferred Rent Receivables, net	'		'
Deferred rent receivables	141,899	[2]	129,198
Allowance for deferred rent receivables	-1,989	[2]	-2,075
Deferred rent receivables, net	$139,910	[2]	$127,123
[1]	Excludes current receivables, net related to properties held for sale at September 30, 2014.
[2]	Excludes deferred rent receivables, net related to properties held for sale at September 30, 2014.

Secured_Debt_Details

Secured Debt (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Debt Instrument [Line Items]	'		'
Secured Debt	$549,896	[1]	$560,434	[1]
Kilroy Realty, L.P. [Member]	'		'
Debt Instrument [Line Items]	'		'
Secured Debt	549,896		560,434
Kilroy Realty, L.P. [Member] | Secured Debt [Member] | 4.27% Mortgage Payable due Feb. 01, 2018 [Member]	'		'
Debt Instrument [Line Items]	'		'
Annual Stated Interest Rate	4.27%	[2]	'
Effective interest rate	4.27%	[2],[3]	'
Maturity Date	1-Feb-18		'
Secured Debt	131,363	[1]	133,117	[1]
Kilroy Realty, L.P. [Member] | Secured Debt [Member] | 4.48% Mortgage Payable due July 1, 2027 [Member]	'		'
Debt Instrument [Line Items]	'		'
Annual Stated Interest Rate	4.48%	[2]	'
Effective interest rate	4.48%	[2],[3]	'
Maturity Date	1-Jul-27		'
Secured Debt	97,000	[1],[4]	97,000	[1],[4]
Kilroy Realty, L.P. [Member] | Secured Debt [Member] | 6.05% Mortgage Payable Due June 1, 2019 [Member]	'		'
Debt Instrument [Line Items]	'		'
Annual Stated Interest Rate	6.05%	[2]	'
Effective interest rate	3.50%	[2],[3]	'
Maturity Date	1-Jun-19		'
Secured Debt	90,065	[1],[4]	92,502	[1],[4]
Kilroy Realty, L.P. [Member] | Secured Debt [Member] | 6.51% Mortgage Payable due Feb. 01, 2017 [Member]	'		'
Debt Instrument [Line Items]	'		'
Annual Stated Interest Rate	6.51%	[2]	'
Effective interest rate	6.51%	[2],[3]	'
Maturity Date	1-Feb-17		'
Secured Debt	66,907	[1]	67,663	[1]
Kilroy Realty, L.P. [Member] | Secured Debt [Member] | 5.23% Mortgage Payable due Jan. 01, 2016 [Member]	'		'
Debt Instrument [Line Items]	'		'
Annual Stated Interest Rate	5.23%	[2]	'
Effective interest rate	3.50%	[2],[3]	'
Maturity Date	1-Jan-16		'
Secured Debt	53,243	[1],[4]	54,570	[1],[4]
Kilroy Realty, L.P. [Member] | Secured Debt [Member] | 5.57% Morgage Payable Due Feb. 11, 2016 [Member]	'		'
Debt Instrument [Line Items]	'		'
Annual Stated Interest Rate	5.57%	[2]	'
Effective interest rate	3.25%	[2],[3]	'
Maturity Date	11-Feb-16		'
Secured Debt	40,611	[1],[4]	41,654	[1],[4]
Kilroy Realty, L.P. [Member] | Secured Debt [Member] | 5.09% Mortgage Payable due Aug. 7, 2015 [Member]	'		'
Debt Instrument [Line Items]	'		'
Annual Stated Interest Rate	5.09%	[2]	'
Effective interest rate	3.50%	[2],[3]	'
Maturity Date	7-Aug-15		'
Secured Debt	34,446	[1],[4]	34,845	[1],[4]
Kilroy Realty, L.P. [Member] | Secured Debt [Member] | 4.94% Mortgage Payable due April 15, 2015 [Member]	'		'
Debt Instrument [Line Items]	'		'
Annual Stated Interest Rate	4.94%	[2]	'
Effective interest rate	4.00%	[2],[3]	'
Maturity Date	15-Apr-15		'
Secured Debt	26,629	[1],[4]	27,641	[1],[4]
Kilroy Realty, L.P. [Member] | Secured Debt [Member] | 7.15% Mortgage Payable due May 01, 2017 [Member]	'		'
Debt Instrument [Line Items]	'		'
Annual Stated Interest Rate	7.15%	[2]	'
Effective interest rate	7.15%	[2],[3]	'
Maturity Date	1-May-17		'
Secured Debt	7,185	[1]	8,972	[1]
Kilroy Realty, L.P. [Member] | Secured Debt [Member] | Municipal Bonds [Member]	'		'
Debt Instrument [Line Items]	'		'
Secured Debt	$2,447	[1]	$2,470	[1]
[1]	Amounts reported include the amounts of unamortized debt premiums and discounts for the periods presented.
[2]	All interest rates presented are fixed-rate interest rates.
[3]	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.
[4]	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.

Exhangeable_Senior_Notes_Detai

Exhangeable Senior Notes (Details) (USD $)	3 Months Ended			9 Months Ended			12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Dec. 31, 2013
Balance and significant terms of the Exchangeable Notes outstanding	'		'	'		'	'
Net carrying amount of liability component	$135,049,000		'	$135,049,000		'	$168,372,000
Kilroy Realty, L.P. [Member]	'		'	'		'	'
Balance and significant terms of the Exchangeable Notes outstanding	'		'	'		'	'
Net carrying amount of liability component	135,049,000		'	135,049,000		'	168,372,000
Exchangeable Debt [Member] | Kilroy Realty, L.P. [Member]	'		'	'		'	'
Debt Instrument [Line Items]	'		'	'		'	'
Referenced shares of common stock under capped call	3,770,531	[1]	'	3,770,531	[1]	'	4,800,796	[1]
Exchange price including effect of capped calls	42.81		'	42.81		'	42.81
Contractual interest payments	1,439,000		1,833,000	4,908,000		5,498,000	'
Amortization of discount	1,004,000		1,116,000	3,337,000		3,291,000	'
Interest Expense attributable to the Exchangeable Notes	2,443,000		2,949,000	8,245,000		8,789,000	'
Balance and significant terms of the Exchangeable Notes outstanding	'		'	'		'	'
Long-term Debt, Gross	135,481,000		172,500,000	135,481,000		172,500,000	172,500,000
Unamortized discount	-432,000		'	-432,000		'	-4,128,000
Net carrying amount of liability component	135,049,000		'	135,049,000		'	168,372,000
Carrying amount of equity component	15,578,000	[2]	'	15,578,000	[2]	'	19,835,000	[3]
Issuance Date	'		'	16-Nov-09		'	'
Maturity Date	'		'	15-Nov-14		'	'
Stated coupon rate	4.25%	[4]	'	4.25%	[4]	'	'
Effective interest rate	7.13%	[5]	'	7.13%	[5]	'	'
Exchange rate per $1,000 principal value of the Exchangeable Notes, as adjusted	'		'	27.8307	[5]	'	'
Exchange price, as adjusted	'		'	$35.93	[6]	'	'
Number of Shares on which aggregate consideration to be delivered upon conversion is determined	'		'	3,770,531	[6]	'	4,800,796	[6]
Average trading price of the Companys stock	$62.06		$51.57	$59.27		$52.42	'
Fair Value Of Shares Upon Conversion If Exchangeable Notes Were Converted On Specified Date	229,840,000		245,200,000	223,732,000		248,000,000	'
Debt Instrument, Convertible, If-converted Value in Excess of Principal	94,359,000		72,700,000	88,251,000		75,500,000	'
Term Loan Facility [Member] | Line of Credit [Member] | Kilroy Realty, L.P. [Member]	'		'	'		'	'
Balance and significant terms of the Exchangeable Notes outstanding	'		'	'		'	'
Maturity Date	'		'	1-Jul-19		'	29-Mar-16
Debt Instrument, Basis Spread on Variable Rate	'		'	1.40%		'	1.75%
Exchangeable Note Two [Member] | Exchangeable Debt [Member] | Kilroy Realty, L.P. [Member]	'		'	'		'	'
Balance and significant terms of the Exchangeable Notes outstanding	'		'	'		'	'
Minimum percentage of exchange price	'		'	130.00%		'	'
Notes exchanged during 2014 [Member] | Exchangeable Debt [Member] | Kilroy Realty, L.P. [Member]	'		'	'		'	'
Balance and significant terms of the Exchangeable Notes outstanding	'		'	'		'	'
Long-term Debt, Gross	$37,000,000		'	$37,000,000		'	'
Exchangeable Note One [Member] | Exchangeable Debt [Member] | Kilroy Realty, L.P. [Member]	'		'	'		'	'
Debt Instrument [Line Items]	'		'	'		'	'
Number of trading days used for calculation of shares of common stock delivered for settlement	'		'	30		'	'
Common Stock [Member]	'		'	'		'	'
Balance and significant terms of the Exchangeable Notes outstanding	'		'	'		'	'
Common shares issued in connection with early exchange of 4.25% Exchangeable Senior Notes (Note 5), shares	'		'	431,270		'	'
Common shares received in connection with capped call option transactions (Note 5)	'		'	111,206		'	'
Common Stock, Issued, Net of Capped Calls	'		'	320,064		'	'
[1]	The referenced shares of common stock decreased during the nine months ended September 30, 2014 as a result of the settled exchanges of the 4.25% Exchangeable Notes totaling $37.0 million.
[2]	(1)The $15.6 million carrying amount of the equity component at September 30, 2014 represents the proportionate amount of the initial $19.8 million carrying value of the equity component allocated to the remaining $135.5 million outstanding principal balance of the 4.25% Exchangeable Notes at September 30, 2014.
[3]	All interest rates presented are fixed-rate interest rates.
[4]	Interest on the 4.25% Exchangeable Notes is payable semi-annually in arrears on May 15th and November 15th of each year.
[5]	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.
[6]	The exchange rate, exchange price and the number of shares to be delivered upon conversion are subject to adjustment under certain circumstances including increases in our common dividends.

Unsecured_Senior_Notes_Details

Unsecured Senior Notes (Details) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2014		Dec. 31, 2013
Debt Instrument [Line Items]	'		'
Unsecured debt	$1,743,962,000		1,431,132,000
Exchangeable senior notes, net	135,049,000		168,372,000
Kilroy Realty, L.P. [Member]	'		'
Debt Instrument [Line Items]	'		'
Unsecured debt	1,743,962,000		1,431,132,000
Exchangeable senior notes, net	135,049,000		168,372,000
Kilroy Realty, L.P. [Member] | Revolving Credit Facility [Member]	'		'
Debt Instrument [Line Items]	'		'
Debt Instrument, Basis Spread on Variable Rate	1.25%		1.45%
Debt Instrument, Contingent Additional Borrowings	300,000,000		'
Kilroy Realty, L.P. [Member] | Four Point Two Five Zero Percent Unsecured Senior Notes [Member] [Domain] | Senior Notes [Member]	'		'
Debt Instrument [Line Items]	'		'
Stated coupon rate	4.25%		'
Effective interest rate	4.35%	[1],[2]	'
Debt Instrument, Face Amount	400,000,000		0
Debt Instrument, Unamortized Discount	-4,422,000		0
Unsecured debt	395,578,000		0
Kilroy Realty, L.P. [Member] | 3.800% Unsecured Senior Note [Member] | Senior Notes [Member]	'		'
Debt Instrument [Line Items]	'		'
Stated coupon rate	3.80%		'
Effective interest rate	3.80%	[1],[3]	'
Debt Instrument, Face Amount	300,000,000		300,000,000
Debt Instrument, Unamortized Discount	-82,000		-90,000
Unsecured debt	299,918,000		299,910,000
Kilroy Realty, L.P. [Member] | 4.800% Unsecured Senior Notes Due July Fifteen Two Thousand Eighteen [Member] | Senior Notes [Member]	'		'
Debt Instrument [Line Items]	'		'
Stated coupon rate	4.80%		'
Effective interest rate	4.83%	[1],[4]	'
Debt Instrument, Face Amount	325,000,000		325,000,000
Debt Instrument, Unamortized Discount	-283,000		-339,000
Unsecured debt	324,717,000		324,661,000
Kilroy Realty, L.P. [Member] | 6.625% Unsecured Senior Notes due June 1 2020 [Member] | Senior Notes [Member]	'		'
Debt Instrument [Line Items]	'		'
Stated coupon rate	6.63%		'
Effective interest rate	6.74%	[1],[5]	'
Debt Instrument, Face Amount	250,000,000		250,000,000
Debt Instrument, Unamortized Discount	-1,207,000		-1,367,000
Unsecured debt	248,793,000		248,633,000
Kilroy Realty, L.P. [Member] | 5.000% Unsecured Senior Notes due Nov3 2015 [Member] | Senior Notes [Member]	'		'
Debt Instrument [Line Items]	'		'
Stated coupon rate	5.00%		'
Effective interest rate	5.01%	[1],[6]	'
Debt Instrument, Face Amount	325,000,000		325,000,000
Debt Instrument, Unamortized Discount	-44,000		-73,000
Unsecured debt	324,956,000		324,927,000
Kilroy Realty, L.P. [Member] | 6.45% Unsecured Senior Notes due Aug 4 2014 [Member] | Senior Notes [Member]	'		'
Debt Instrument [Line Items]	'		'
Effective interest rate	'		6.45%
Unsecured debt	'		83,000,000
Kilroy Realty, L.P. [Member] | Term Loan Facility [Member] | Line of Credit [Member]	'		'
Debt Instrument [Line Items]	'		'
Maturity Date	1-Jul-19		29-Mar-16
Unsecured debt	$150,000,000		150,000,000
Debt Instrument, Basis Spread on Variable Rate	1.40%		1.75%
[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 the 4.250% unsecured senior notes is payable semi-annually in arrears on February 15th and August 15th of each year.
[3]	Interest on the 3.800% unsecured senior notes is payable semi-annually in arrears on January 15th and July 15th of each year.
[4]	Interest on the 4.800% unsecured senior notes is payable semi-annually in arrears on January 15th and July 15th of each year.
[5]	Interest on the 6.625% unsecured senior notes is payable semi-annually in arrears on June 1st and December 1st of each year.
[6]	Interest on the 5.000% unsecured senior notes is payable semi-annually in arrears on May 3rd and November 3rd of each year.

Unsecured_Revolving_Credit_Fac

Unsecured Revolving Credit Facility (Details 3) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2014		Dec. 31, 2013
Debt Instrument [Line Items]	'		'
Unsecured debt	$1,743,962,000		$1,431,132,000
Terms of the Credit Facility	'		'
Unsecured line of credit	0		45,000,000
Kilroy Realty, L.P. [Member]	'		'
Debt Instrument [Line Items]	'		'
Unsecured debt	1,743,962,000		1,431,132,000
Terms of the Credit Facility	'		'
Unsecured line of credit	0		45,000,000
Kilroy Realty, L.P. [Member] | Revolving Credit Facility [Member]	'		'
Terms of the Credit Facility	'		'
Unsecured line of credit	0		45,000,000
Remaining borrowing capacity	600,000,000		455,000,000
Total borrowing capacity	600,000,000	[1]	500,000,000	[1]
Interest rate	0.00%	[2]	1.62%	[3]
Facility fee - annual rate	0.25%	[4]	0.30%
Maturity date	1-Jul-19		3-Apr-17
Debt Instrument, Contingent Additional Borrowings	300,000,000		'
Debt Instrument, Basis Spread on Variable Rate	1.25%		1.45%
Debt Issuance Cost	$6,200,000		'
[1]	We may elect to borrow, subject to bank approval and obtaining commitments for any additional borrowing capacity, up to an additional $300.0 million under an accordion feature under the terms of the unsecured revolving credit facility and term loan facility.
[2]	Our revolving credit facility interest rate was calculated based on an annual rate of LIBOR plus 1.250% as of September 30, 2014.
[3]	Our revolving credit facility interest rate was calculated based on an annual rate of LIBOR plus 1.450% as of December 31, 2013
[4]	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 September 30, 2014, $6.2 million of deferred financing costs remains to be amortized through the amended maturity date of our unsecured revolving credit facility.

Debt_Maturities_Details

Debt Maturities (Details) (Debt [Member], Kilroy Realty, L.P. [Member], USD $)	Sep. 30, 2014
Debt [Member] | Kilroy Realty, L.P. [Member]	'
Stated debt maturities and scheduled amortization payments, excluding debt discounts	'
Remaining 2014	$138,009,000
2015	395,104,000
2016	99,431,000
2017	71,748,000
2018	451,728,000
Thereafter	1,268,013,000
Total	2,424,033,000	[1]
Unamortized premium	($4,900,000)
[1]	Includes gross principal balance of outstanding debt before impact of net unamortized premiums totaling approximately $4.9 million

Secured_and_Unsecured_Debt_of_2

Secured and Unsecured Debt of the Operating Partnership Capitalized Interest and Loan Fees (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Capitalized Interest and Loan Fees [Line Items]	'	'	'	'
Interest Expense	$16,608	$18,853	$49,880	$58,021
Kilroy Realty, L.P. [Member]	'	'	'	'
Capitalized Interest and Loan Fees [Line Items]	'	'	'	'
Gross interest expense	29,936	27,942	85,740	83,322
Capitalized interest	-13,328	-9,089	-35,860	-25,301
Interest Expense	$16,608	$18,853	$49,880	$58,021

Noncontrolling_Interests_on_th1

Noncontrolling Interests on the Company's Consolidated Financial Statements (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Noncontrolling Interest [Abstract]	'	'	'
Percentage of general partnership interest owned by the company in the Operating Partnership	97.90%	97.80%	97.80%
Percentage of Common limited partnership interest owned by certain non-affiliated investors and certain directors and officers of the Company in the Operating Partnership	2.10%	2.20%	2.20%
Common units outstanding held by common limited partners	1,804,200	1,805,200	1,821,503
Common stock, par value	$0.01	'	'
Aggregate value upon redemption of outstanding noncontrolling common units	$107,800,000	$90,800,000	'
Noncontrolling Interest in Variable Interest Entity	$5,222,000	$4,885,000	'

Stockholders_Equity_of_the_Com2

Stockholders' Equity of the Company (Details) (USD $)	9 Months Ended					9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014
			Common Stock [Member]	Common Stock [Member]	Issuance of Equity - at the market offering [Member]	Issuance of Equity under ATM Program [Member]	Issuance of Equity under ATM Program [Member]
					Common Stock [Member]		Common Stock [Member]
Common Stock of the Company [Abstract]	'	'	'	'	'	'	'
Issuance of common stock (Note 7), shares	'	'	'	'	'	'	370,700
Average price per common shares sold	'	'	'	'	'	'	$61.01
At the Market Stock Offering Program Aggregate Value Of Common Stock	'	'	'	'	'	$200,000,000	'
Net proceeds from issuance of common stock (Note 7)	22,136,000	349,951,000	'	'	'	'	22,600,000
Common stock, shares issued	'	'	83,388,220	82,153,944	'	2,553,961	'
At Market Stock Aggregate Gross Sales Price of Common Stock	'	'	'	'	127,900,000	'	'
At the Market Stock Offering Program Remained Available For Issuance	'	'	'	'	'	'	72,100,000
Proceeds from Issuance of Common stock, net	'	'	'	'	'	'	$22,300,000

Partners_Capital_of_the_Operat2

Partners' Capital of the Operating Partnership (Details) (USD $)	9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
General Partners' Capital Account [Abstract]	'	'	'
Net proceeds from issuance of common stock	$22,136	$349,951	'
Noncontrolling Interest, Ownership Percentage by Parent	97.90%	97.80%	97.80%
Common units held by limited partners	1,804,200	1,821,503	1,805,200
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	2.10%	2.20%	2.20%
Kilroy Realty, L.P. [Member] | Capital Units [Member]	'	'	'
General Partners' Capital Account [Abstract]	'	'	'
General Partners' Capital Account, Units Outstanding	83,388,220	82,113,491	82,153,944

ShareBased_Compensation_Detail

Share-Based Compensation (Details Textuals) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

9 Months Ended

In Millions, except Share data, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

22-May-14

Mar. 31, 2014

Mar. 31, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Market Measure-Based Restricted Stock Units (RSUs) [Member]

Market Measure-Based Restricted Stock Units (RSUs) [Member]

Time-Based Restricted Stock Units (RSUs) [Member]

Employee Stock Option [Member]

Kilroy Realty 2006 Incentive Award Plan [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Shareholder Meeting Date May 22, 2014 [Domain]

Employee Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common shares received in connection with capped call option transactions (Note 5)

'

'

'

'

'

'

'

'

'

'

'

111,206

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Requested

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7,120,000

Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price

'

'

'

'

'

'

'

'

'

$42.61

'

'

'

'

'

Shares Paid for Tax Withholding for Share Based Compensation

'

'

'

'

'

'

'

'

'

'

'

48,017

34,164

22,162

'

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant

'

'

'

'

'

'

'

'

'

'

728,865

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

'

'

'

'

'

'

$63.44

$65.03

'

'

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate

'

'

'

'

'

'

'

24.00%

'

'

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate

'

'

'

'

'

'

'

0.61%

'

'

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

'

'

236,604

'

'

'

'

119,098

117,506

'

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term

'

'

'

'

'

'

'

'2 years 7 months

'

'

'

'

'

'

'

Share Price

'

'

'

'

$60.16

$51.64

'

'

'

'

'

'

'

'

'

Exercise of stock options, net, shares

'

'

'

'

'

'

'

'

'

'

'

482,000

473

'

'

Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Grants In Period, Grant Date Fair Value

'

'

'

'

'

'

'

$7.70

$7.10

'

'

'

'

'

'

Share-based Compensation Capitalized

0.6

0.2

1.5

0.6

'

'

'

'

'

'

'

'

'

'

'

Share-based Compensation, Unrecognized costs

34.4

'

34.4

'

'

'

'

'

'

'

'

'

'

'

'

Share-based Compensation, Unrecognized costs, weighted-average vesting period

'

'

'2 years 9 months

'

'

'

'

'

'

'

'

'

'

'

'

Allocated Share-based Compensation Expense

$4

$2.50

$10.30

$7.20

'

'

'

'

'

'

'

'

'

'

'

Commitments_and_Contingencies_

Commitments and Contingencies (Details 1) (USD $)	Sep. 30, 2014
In Millions, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'
Other Commitment	$514.70

Fair_Value_Measurements_and_Di2

Fair Value Measurements and Disclosures (Details) (USD $)	3 Months Ended			9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Dec. 31, 2013
Fair value adjustment of marketable securities and deferred compensation plan liability	'		'	'		'	'
Net gain on marketable securities	($39)		$669	$507		$995	'
Trading Securities	12,076		'	12,076		'	10,008
Fair Value (Level 1) [Member]	'		'	'		'	'
Assets and Liabilities Reported at Fair Value	'		'	'		'	'
Marketable securities	$12,076	[1],[2]	'	$12,076	[1],[2]	'	$10,008	[1],[2]
[1]	The marketable securities are held in a limited rabbi trust.
[2]	Based on quoted prices in active markets for identical securities.

Fair_Value_Measurements_and_Di3

Fair Value Measurements and Disclosures (Details 1) (USD $)	Sep. 30, 2014		Dec. 31, 2013
Liabilities	'		'
Secured Debt	$549,896,000	[1]	$560,434,000	[1]
Exchangeable senior notes, net	135,049,000		168,372,000
Unsecured debt	1,743,962,000		1,431,132,000
Unsecured line of credit	0		45,000,000
Carrying Value	'		'
Liabilities	'		'
Secured Debt	549,896,000	[2]	560,434,000	[2]
Exchangeable senior notes, net	135,049,000	[2]	168,372,000	[2]
Unsecured debt	1,743,962,000	[3]	1,431,132,000	[3]
Unsecured line of credit	0	[2]	45,000,000	[2]
Carrying Value | Fair Value (Level 2) [Member]	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	474,700,000		557,700,000
Carrying Value | Unsecured Debt [Member] | Fair Value (Level 1) [Member]	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	1,269,200,000		873,500,000
Fair Value	'		'
Liabilities	'		'
Secured Debt	557,217,000	[2]	568,760,000	[2]
Exchangeable senior notes, net	135,770,000	[2]	178,190,000	[2]
Unsecured debt	1,825,725,000	[3]	1,523,052,000	[3]
Unsecured line of credit	0	[2]	45,012,000	[2]
Fair Value | Fair Value (Level 2) [Member]	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	500,600,000		593,700,000
Fair Value | Unsecured Debt [Member] | Fair Value (Level 1) [Member]	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	$1,325,000,000		$929,300,000
[1]	Amounts reported include the amounts of unamortized debt premiums and discounts for the periods presented.
[2]	Fair value calculated using Level II inputs, which are based on model-derived valuations in which significant inputs and significant value drivers are observable in active markets.
[3]	Fair value calculated using Level I and Level II inputs. Level I inputs are based on quoted prices for identical instruments in active markets. The carrying value and fair value of the Level I instruments was $1,269.2 million and $1,325.0 million, respectively, as of September 30, 2014. The carrying value and fair value of the Level I instruments as of December 31, 2013, was $873.5 million and $929.3 million, respectively. The carrying value and fair value of the Level II instruments was $474.7 million and $500.6 million, respectively, as of September 30, 2014. The carrying value and fair value of the Level II instruments as of December 31, 2013, was $557.7 million and $593.7 million, respectively.

Other_Significant_Events_Detai

Other Significant Events (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Other Significant Noncash Transactions [Line Items]	'	'
Net Rentable Area	79,000	79,000
Lease termination fee, total contract amount	$5,700,000	$5,700,000
Lease Termination	'	'
Other Significant Noncash Transactions [Line Items]	'	'
Lease Termination Fee, amount recognized in the quarter	2,000,000	5,700,000
Amortization of Intangible Assets	$400,000	$1,300,000

Discontinued_Operations_Detail

Discontinued Operations (Details) (USD $)

3 Months Ended

9 Months Ended

9 Months Ended

12 Months Ended

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

sqft

sqft

San Diego Properties, San Diego [Member]

10850 Via Frontera San Diego CA [Member]

4040 Civic Center [Member]

9785&9791 Towne Centre Drive, San Diego CA [Member]

111 Pacifica [Member] [Member]

2014 Dispositions [Member]

999 Town &Country[Member] [Member]

Restricted cash [Member]

Properties Held for Sale [Member]

building

sqft

sqft

sqft

sqft

sqft

building

sqft

building

building

building

building

building

sqft

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Gain on sale of land (Note 13)

$0

$0

$3,490,000

$0

'

'

'

'

'

'

'

'

'

'

Dispositions Sales Price

'

'

'

'

'

'

33,100,000

'

'

'

'

'

'

'

Number of buildings

'

'

'

'

'

12

[1]

'

1

2

1

15

1

'

2

[2]

Proceeds from Sale of Real Estate Held-for-investment

'

'

368,381,000

14,409,000

'

'

'

'

'

'

'

'

32,200,000

'

Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Land and improvements

18,077,000

'

18,077,000

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Buildings and Improvements

31,530,000

'

31,530,000

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Total real estate held-for-sale

49,607,000

'

49,607,000

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Accumulated depreciation and amortization

5,046,000

'

5,046,000

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Total real estate held for sale, net

44,561,000

'

44,561,000

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Current receivables, net

56,000

'

56,000

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Deferred rent receivables, net

1,241,000

'

1,241,000

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Deferred leasing costs and acquisition-related intangible assets, net

3,754,000

'

3,754,000

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Prepaid expenses and other assets, net

203,000

'

203,000

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Real estate and other assets held for sale, net

49,815,000

'

49,815,000

'

213,100,000

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Accounts payable, accrued expenses and other liabilities

944,000

'

944,000

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Deferred revenue and acquisition-related intangible liabilities, net

1,733,000

'

1,733,000

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Rents received in advance and tenant security deposits

422,000

'

422,000

'

'

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operations, Liabilities and deferred revenue of real estate assets held for sale

3,099,000

'

3,099,000

'

14,447,000

'

'

'

'

'

'

'

'

'

Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Rental income

1,982,000

8,189,000

6,361,000

23,692,000

'

'

'

'

'

'

'

'

'

'

Tenant reimbursements

70,000

918,000

247,000

2,420,000

'

'

'

'

'

'

'

'

'

'

Other property income

6,000

5,151,000

26,000

5,159,000

'

'

'

'

'

'

'

'

'

'

Total revenues

2,058,000

14,258,000

6,634,000

31,271,000

'

'

'

'

'

'

'

'

'

'

Property expenses

705,000

2,673,000

1,952,000

5,753,000

'

'

'

'

'

'

'

'

'

'

Real estate taxes

196,000

891,000

628,000

2,626,000

'

'

'

'

'

'

'

'

'

'

Depreciation and amortization

609,000

4,846,000

1,963,000

11,693,000

'

'

'

'

'

'

'

'

'

'

Total expenses

1,510,000

8,410,000

4,543,000

20,072,000

'

'

'

'

'

'

'

'

'

'

Income from discontinued operations

548,000

5,848,000

2,091,000

11,199,000

'

'

'

'

'

'

'

'

'

'

Gains on dispositions of discontinued operations

5,587,000

0

110,391,000

423,000

'

'

'

'

'

'

'

'

'

'

Total income from discontinued operations

$6,135,000

$5,848,000

$112,482,000

$11,622,000

'

'

'

'

'

'

'

'

'

'

Net Rentable Area

79,000

'

79,000

'

'

1,049,035

[1]

'

130,237

126,000

67,496

1,242,531

98,551

'

228,788

[2]

[1]

The San Diego Properties included the following: 10020 Pacific Mesa Boulevard, 6055 Lusk Avenue, 5010 and 5005 Wateridge Vista Drive, 15435 and 15445 Innovation Drive, and 15051, 15073, 15231, 15253, 15333 and 15378 Avenue of Science. These properties were held for sale as of December 31, 2013.

[2]

Includes two properties, one located in Orange, California and the other in the San Rafael submarket of San Francisco, California.

Net_Income_Available_to_Common4

Net Income Available to Common Stockholders Per Share of the Company (Details) (USD $)	3 Months Ended				9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Numerator:	'		'		'		'
Income from continuing operations	$13,168		$3,179		$39,896		$9,896
(Income) Loss from continuing operations attributable to noncontrolling common units of the Operating Partnership	-193		3		-635		2
Preferred dividends	-3,313		-3,312		-9,938		-9,938
Allocation to participating securities	-432	[1]	-450	[1]	-1,285	[1]	-1,292	[1]
Numerator for basic and diluted income from continuing operations available to common stockholders	9,230		-580		28,038		-1,332
Income from discontinued operations	6,135		5,848		112,482		11,622
Income from discontinued operations attributable to noncontrolling common units of the Operating Partnership	-128		-134		-2,376		-268
Numerator for basic and diluted net income available to common stockholders	15,237		5,134		138,144		10,022
Denominator:	'		'		'		'
Weighted average common shares outstanding – basic (Note 14)	83,161,323		76,768,893		82,525,033		75,750,822
Effect of dilutive securities	1,949,133		0		2,097,589		0
Weighted average common shares outstanding-diluted	85,110,456		76,768,893		84,622,622		75,750,822
Basic earnings per share:	'		'		'		'
Income (loss) from continuing operations available to common stockholders per common share – basic (Note 14)	$0.11		$0		$0.34		($0.02)
Income from discontinued operations per common share	$0.07		$0.07		$1.33		$0.15
Net income available to common stockholders per share-basic	$0.18		$0.07		$1.67		$0.13
Diluted earnings per share:	'		'		'		'
Income (loss) from continuing operations available to common stockholders per common share – diluted (Note 14)	$0.11		$0		$0.33		($0.02)
Income from discontinued operations per common share	$0.07		$0.07		$1.30		$0.15
Net income available to common stockholders per share-diluted	$0.18		$0.07		$1.63		$0.13
Kilroy Realty, L.P. [Member]	'		'		'		'
Numerator:	'		'		'		'
Income from continuing operations	13,168		3,179		39,896		9,896
Preferred dividends	-3,313		-3,312		-9,938		-9,938
Allocation to participating securities	-432	[1]	-450	[1]	-1,285	[1]	-1,292	[1]
Numerator for basic and diluted income from continuing operations available to common stockholders	9,364		-630		28,472		-1,512
Income from discontinued operations	6,135		5,848		112,482		11,622
Numerator for basic and diluted net income available to common stockholders	$15,499		$5,218		$140,954		$10,110
Denominator:	'		'		'		'
Weighted average common shares outstanding – basic (Note 14)	84,965,523		78,590,396		84,329,317		77,574,907
Effect of dilutive securities	1,949,133		0		2,097,589		0
Weighted average common shares outstanding-diluted	86,914,656		78,590,396		86,426,906		77,574,907
Basic earnings per share:	'		'		'		'
Income (loss) from continuing operations available to common stockholders per common share – basic (Note 14)	$0.11		$0		$0.34		($0.02)
Income from discontinued operations per common share	$0.07		$0.07		$1.33		$0.15
Net income available to common stockholders per share-basic	$0.18		$0.07		$1.67		$0.13
Diluted earnings per share:	'		'		'		'
Income (loss) from continuing operations available to common stockholders per common share – diluted (Note 14)	$0.11		$0		$0.33		($0.02)
Income from discontinued operations per common share	$0.07		$0.07		$1.30		$0.15
Net income available to common stockholders per share-diluted	$0.18		$0.07		$1.63		$0.13
[1]	Participating securities include nonvested shares, certain time-based RSUs and vested market measure-based RSUs.

Net_Income_Available_to_Common5

Net Income Available to Common Unitholders Per Unit of the Operating Partnership (Details) (USD $)	3 Months Ended				9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Numerator:	'		'		'		'
Income from continuing operations	$13,168		$3,179		$39,896		$9,896
Preferred distributions	-3,313		-3,312		-9,938		-9,938
Allocation to participating securities	-432	[1]	-450	[1]	-1,285	[1]	-1,292	[1]
Numerator for basic and diluted income from continuing operations available to common unitholders	9,230		-580		28,038		-1,332
Income from discontinued operations	6,135		5,848		112,482		11,622
Numerator for basic and diluted net income available to common unitholders	15,237		5,134		138,144		10,022
Denominator:	'		'		'		'
Weighted average common units outstanding - basic (Note 15)	83,161,323		76,768,893		82,525,033		75,750,822
Effect of dilutive securities	1,949,133		0		2,097,589		0
Weighted average common units outstanding - diluted (Note 15)	85,110,456		76,768,893		84,622,622		75,750,822
Basic earnings per unit:	'		'		'		'
Income (loss) from continuing operations available to common unitholders per unit - basic (Note 15)	$0.11		$0		$0.34		($0.02)
Income from discontinued operations per common unit	$0.07		$0.07		$1.33		$0.15
Net income available to common unitholders per unit-basic (Note 15)	$0.18		$0.07		$1.67		$0.13
Diluted earnings per unit:	'		'		'		'
Income (loss) from continuing operations available to common unitholders per unit - diluted (Note 15)	$0.11		$0		$0.33		($0.02)
Income from discontinued operations per common unit	$0.07		$0.07		$1.30		$0.15
Net income available to common unitholders per unit-diluted (Note 15)	$0.18		$0.07		$1.63		$0.13
Kilroy Realty, L.P. [Member]	'		'		'		'
Numerator:	'		'		'		'
Income from continuing operations	13,168		3,179		39,896		9,896
Income from continuing operations attributable to noncontrolling interests in consolidated subsidiaries	-59		-47		-201		-178
Preferred distributions	-3,313		-3,312		-9,938		-9,938
Allocation to participating securities	-432	[1]	-450	[1]	-1,285	[1]	-1,292	[1]
Numerator for basic and diluted income from continuing operations available to common unitholders	9,364		-630		28,472		-1,512
Income from discontinued operations	6,135		5,848		112,482		11,622
Numerator for basic and diluted net income available to common unitholders	$15,499		$5,218		$140,954		$10,110
Denominator:	'		'		'		'
Weighted average common units outstanding - basic (Note 15)	84,965,523		78,590,396		84,329,317		77,574,907
Effect of dilutive securities	1,949,133		0		2,097,589		0
Weighted average common units outstanding - diluted (Note 15)	86,914,656		78,590,396		86,426,906		77,574,907
Basic earnings per unit:	'		'		'		'
Income (loss) from continuing operations available to common unitholders per unit - basic (Note 15)	$0.11		$0		$0.34		($0.02)
Income from discontinued operations per common unit	$0.07		$0.07		$1.33		$0.15
Net income available to common unitholders per unit-basic (Note 15)	$0.18		$0.07		$1.67		$0.13
Diluted earnings per unit:	'		'		'		'
Income (loss) from continuing operations available to common unitholders per unit - diluted (Note 15)	$0.11		$0		$0.33		($0.02)
Income from discontinued operations per common unit	$0.07		$0.07		$1.30		$0.15
Net income available to common unitholders per unit-diluted (Note 15)	$0.18		$0.07		$1.63		$0.13
[1]	Participating securities include nonvested shares, certain time-based RSUs and vested market measure-based RSUs.

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	9 Months Ended		0 Months Ended		1 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Oct. 15, 2014	Oct. 03, 2014	Oct. 23, 2014
			Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]
					SFFGA [Member]
Subsequent Event [Line Items]	'	'	'	'	'
purchase price, cash paid to acquire land	'	'	'	'	$5,400,000
Average price per common shares sold	'	'	'	$59.38	'
purchase price, value of shares issued to acquire land	'	'	'	'	21,600,000
Common Stock, Shares, Issued	'	'	'	217,042	351,476
Aggregate dividends, distributions, and dividend equivalents paid to common stockholders and common unitholders	88,540,000	82,152,000	30,300,000	'	'
purchase price, land acquisition	'	'	'	'	$27,000,000