Kilroy Realty (KRC) 10-Q 26 Oct 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 20, 2017
Entity Registrant Name	KILROY REALTY CORP
Entity Central Index Key	1,025,996
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		98,382,256
Kilroy Realty, L.P. [Member]
Entity Registrant Name	Kilroy Realty, L.P.
Entity Central Index Key	1,493,976
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
REAL ESTATE ASSETS:
Land and improvements	$ 1,076,172	$ 1,108,971
Buildings and improvements	4,871,667	4,938,250
Undeveloped land and construction in progress	1,292,017	1,013,533
Total real estate assets held for investment	7,239,856	7,060,754
Accumulated depreciation and amortization	(1,216,358)	(1,139,853)
Total real estate assets held for investment, net	6,023,498	5,920,901
REAL ESTATE ASSETS AND OTHER ASSETS HELD FOR SALE, NET	0	9,417
CASH AND CASH EQUIVALENTS	64,954	193,418
RESTRICTED CASH (Note 2)	179,276	56,711
MARKETABLE SECURITIES (Note 11)	18,851	14,773
CURRENT RECEIVABLES, NET (Note 3)	18,626	13,460
DEFERRED RENT RECEIVABLES, NET (Note 3)	238,959	218,977
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET	185,420	208,368
PREPAID EXPENSES AND OTHER ASSETS, NET (Note 4)	108,715	70,608
TOTAL ASSETS	6,838,299	6,706,633
LIABILITIES:
Secured debt, net (Notes 5 and 11)	465,828	472,772
Unsecured debt, net (Notes 5 and 11)	1,909,381	1,847,351
Unsecured line of credit (Notes 5 and 11)	60,000	0
Accounts payable, accrued expenses and other liabilities	271,405	202,391
Accrued dividends and distributions (Note 16)	43,324	222,306
Deferred revenue and acquisition-related intangible liabilities, net	145,556	150,360
Rents received in advance and tenant security deposits	46,925	52,080
Liabilities of real estate assets held for sale	0	56
Total liabilities	2,942,419	2,947,316
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, 98,382,256 and 93,219,439 shares issued and outstanding, respectively	984	932
Additional paid-in capital	3,797,546	3,457,649
Distributions in excess of earnings	(108,667)	(107,997)
Total stockholders’ equity	3,689,863	3,542,995
Noncontrolling Interests:
Common units of the Operating Partnership (Note 6)	77,911	85,590
Noncontrolling interests in consolidated property partnerships (Note 1)	128,106	130,732
Total noncontrolling interests	206,017	216,322
Total equity	3,895,880	3,759,317
TOTAL LIABILITIES AND EQUITY (CAPITAL)	6,838,299	6,706,633
6.875% Series G Cumulative Redeemable Preferred stock, $.01 par value, no shares issued and outstanding at 9/30/2017, and 4,000,000 shares authorized, issued and outstanding ($100,000 liquidation preference) at 12/31/2016 [Member]
Preferred stock, $.01 par value, 30,000,000 shares authorized:
Cumulative Redeemable Preferred stock	0	96,155
6.375% Series H Cumulative Redeemable Preferred stock, $.01 par value, no shares issued and outstanding at 9/30/2017, and 4,000,000 shares authorized, issued and outstanding ($100,000 liquidation preference) at 12/31/2016 [Member]
Preferred stock, $.01 par value, 30,000,000 shares authorized:
Cumulative Redeemable Preferred stock	$ 0	$ 96,256

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued (in shares)	98,382,256	93,219,439
Common stock, shares outstanding	98,382,256	93,219,439
Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	30,000,000	30,000,000
Series G Cumulative Redeemable Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0	$ 0.01
Preferred stock, shares authorized	0	4,000,000
Preferred stock, shares issued	0	4,000,000
Preferred stock, shares outstanding	0	4,000,000
Preferred stock dividend rate percentage	0.00%	6.875%
Preferred stock liquidation preference	$ 0	$ 100,000,000
Series H Cumulative Redeemable Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0	$ 0.01
Preferred stock, shares authorized	0	4,000,000
Preferred stock, shares issued	0	4,000,000
Preferred stock, shares outstanding	0	4,000,000
Preferred stock dividend rate percentage	0.00%	6.375%
Preferred stock liquidation preference	$ 0	$ 100,000,000

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
REVENUES
Rental income	$ 159,954	$ 146,539	$ 475,527	$ 423,947
Tenant reimbursements	19,665	16,406	58,228	43,948
Other property income	1,915	5,403	7,685	6,032
Total revenues	181,534	168,348	541,440	473,927
EXPENSES
Property expenses	33,070	30,050	97,615	85,236
Real estate taxes	16,371	14,501	50,878	39,378
Provision for bad debts	1,036	0	2,743	0
Ground leases	1,562	909	4,751	2,506
General and administrative expenses	14,514	13,533	43,750	40,949
Acquisition-related expenses (Note 1)	0	188	0	964
Depreciation and amortization	62,567	56,666	185,737	160,452
Total expenses	129,120	115,847	385,474	329,485
OTHER (EXPENSES) INCOME
Interest income and other net investment gains (Note 11)	1,526	538	3,629	1,120
Interest expense (Note 5)	(16,151)	(14,976)	(51,476)	(41,189)
Total other (expenses) income	(14,625)	(14,438)	(47,847)	(40,069)
INCOME FROM OPERATIONS BEFORE GAINS (LOSS) ON SALES OF REAL ESTATE	37,789	38,063	108,119	104,373
Net gain (loss) on sale of land (Note 2)	449	0	449	(295)
Gains on sales of depreciable operating properties (Note 2)	37,250	18,312	39,507	164,302
NET INCOME	75,488	56,375	148,075	268,380
Net income attributable to noncontrolling common units of the Operating Partnership (Note 6)	(1,394)	(1,453)	(2,633)	(5,892)
Net income attributable to noncontrolling interests in consolidated property partnerships	(2,984)	(1,027)	(9,359)	(1,438)
Total income attributable to noncontrolling interests	(4,378)	(2,480)	(11,992)	(7,330)
NET INCOME ATTRIBUTABLE TO KILROY REALTY CORPORATION (KILROY REALTY, L.P.)	71,110	53,895	136,083	261,050
Preferred dividends	(808)	(3,313)	(5,774)	(9,938)
Original issuance costs of redeemed preferred stock (preferred units)	(3,744)	0	(7,589)	0
Total preferred dividends	(4,552)	(3,313)	(13,363)	(9,938)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS (UNITHOLDERS)	$ 66,558	$ 50,582	$ 122,720	$ 251,112
Net income available to common stockholders per share – basic (in dollars per share) (Note 12)	$ 0.67	$ 0.54	$ 1.24	$ 2.71
Net income available to common stockholders per share – diluted (in dollars per share) (Note 12)	$ 0.67	$ 0.54	$ 1.23	$ 2.69
Weighted average common shares outstanding – basic (in shares) (Note 12)	98,352,139	92,227,016	98,008,780	92,220,522
Weighted average common shares outstanding – diluted (in shares) (Note 12)	98,911,612	92,920,406	98,591,048	92,831,538
Dividends declared per common share (in dollars per share)	$ 0.425	$ 0.375000	$ 1.225	$ 1.1

Consolidated Statements of Equi

Consolidated Statements of Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Common Stock Additional Paid-in Capital [Member]	Common Stock Distributions in Excess of Earnings [Member]	Total Stockholders' Equity [Member]	Noncontrolling Interests [Member]
Beginning balance at Dec. 31, 2015	$ 3,234,586	$ 192,411	$ 923	$ 3,047,894	$ (70,262)	$ 3,170,966	$ 63,620
Beginning balance (in shares) at Dec. 31, 2015			92,258,690
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	268,380				261,050	261,050	7,330
Original issuance costs of redeemed preferred stock (preferred units)	0
Issuance of share-based compensation awards	1,339			1,339		1,339
Non-cash amortization of share-based compensation	19,303			19,303		19,303
Exercise of stock options (Note 9) (in shares)			51,000
Exercise of stock options (Note 9)	2,173			2,173		2,173
Settlement of restricted stock units for shares of common stock, shares			72,130
Settlement of restricted stock units for shares of common stock	0		$ 1	(1)		0
Repurchase of common stock, stock options and restricted stock units, shares			(110,528)
Repurchase of common stock, stock options and restricted stock units	(6,874)		$ (1)	(6,873)		(6,874)
Issuance of common units in connection with acquisition	48,033						48,033
Exchange of common units of the Operating Partnership, shares			1,200
Exchange of common units of the Operating Partnership	0			39		39	(39)
Contributions from noncontrolling interests in consolidated property partnerships	191,676			113,022		113,022	78,654
Distributions to noncontrolling interests in consolidated property partnerships	(1,139)						(1,139)
Adjustment for noncontrolling interest	0			14,822		14,822	(14,822)
Preferred dividends	(9,938)				(9,938)	(9,938)
Dividends declared per common share and common unit ($1.225 and $1.10 per share/unit for the nine months ended September 2017 and 2016, respectively)	(105,637)				(102,743)	(102,743)	(2,894)
Ending balance at Sep. 30, 2016	3,641,902	192,411	$ 923	3,191,718	78,107	3,463,159	178,743
Ending balance (in shares) at Sep. 30, 2016			92,272,492
Beginning balance at Dec. 31, 2016	$ 3,759,317	192,411	$ 932	3,457,649	(107,997)	3,542,995	216,322
Beginning balance (in shares) at Dec. 31, 2016	93,219,439		93,219,439
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 148,075				136,083	136,083	11,992
Redemption of Series G and H Preferred stock (Note 7)	(200,000)	(192,411)				(200,000)
Original issuance costs of redeemed preferred stock (preferred units)	(7,589)				(7,589)
Issuance of common stock, shares (Note 7)			4,427,500
Issuance of common stock (Note 7)	308,812		$ 44	308,768		308,812
Issuance of share-based compensation awards	5,291			5,291		5,291
Non-cash amortization of share-based compensation	19,013			19,013		19,013
Exercise of stock options (Note 9) (in shares)			282,000
Exercise of stock options (Note 9)	12,051		$ 4	12,047		12,051
Settlement of restricted stock units for shares of common stock, shares			317,848
Settlement of restricted stock units for shares of common stock	0		$ 3	(3)		0
Repurchase of common stock, stock options and restricted stock units, shares			(168,881)
Repurchase of common stock, stock options and restricted stock units	(12,986)		$ (2)	(12,984)		(12,986)
Exchange of common units of the Operating Partnership, shares			304,350
Exchange of common units of the Operating Partnership	0		$ 3	10,936		10,939	(10,939)
Contributions from noncontrolling interests in consolidated property partnerships	250					0	250
Distributions to noncontrolling interests in consolidated property partnerships	(12,234)					0	(12,234)
Adjustment for noncontrolling interest	0			(3,171)		(3,171)	3,171
Preferred dividends	(5,774)				(5,774)	(5,774)
Dividends declared per common share and common unit ($1.225 and $1.10 per share/unit for the nine months ended September 2017 and 2016, respectively)	(125,935)				(123,390)	(123,390)	(2,545)
Ending balance at Sep. 30, 2017	$ 3,895,880	$ 0	$ 984	$ 3,797,546	$ (108,667)	$ 3,689,863	$ 206,017
Ending balance (in shares) at Sep. 30, 2017	98,382,256		98,382,256

Consolidated Statements of Equ6

Consolidated Statements of Equity (Unaudited) (Parenthetical) - $ / shares	Dec. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Stockholders' Equity [Abstract]
Dividends declared per common share and common unit (in dollars per share)	$ 1.90	$ 0.425	$ 0.375000	$ 1.225	$ 1.1

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 148,075	$ 268,380
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of real estate assets and leasing costs	181,875	157,587
Depreciation of non-real estate furniture, fixtures and equipment	3,862	2,865
Increase in provision for bad debts	2,743	0
Non-cash amortization of share-based compensation awards	13,617	15,263
Non-cash amortization of deferred financing costs and debt discounts and premiums	2,398	2,020
Non-cash amortization of net below market rents	(6,026)	(5,128)
Gains on sales of depreciable operating properties (Note 2)	(39,507)	(164,302)
(Gain) loss on sale of land (Note 2)	(449)	295
Non-cash amortization of deferred revenue related to tenant-funded tenant improvements	(12,394)	(9,700)
Straight-line rents	(25,537)	(22,856)
Net change in other operating assets	(16,970)	(7,263)
Net change in other operating liabilities	24,855	15,444
Net cash provided by operating activities	276,542	252,605
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for development properties and undeveloped land	(270,839)	(222,719)
Expenditures for operating properties and other capital assets	(61,875)	(81,688)
Net proceeds received from dispositions (Note 2)	182,492	325,031
(Increase) decrease in acquisition-related deposits	(30,490)	1,902
Expenditures for acquisition of operating properties	0	(55,415)
Expenditures for acquisition of undeveloped land	0	(33,513)
Increase in note receivable	0	(1,000)
Net cash used in investing activities	(180,712)	(67,402)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of common stock (Note 7)	308,812	0
Redemption of Series G and H Preferred stock (Note 7)	(200,000)	0
Proceeds from the issuance of unsecured debt (Note 5)	250,000	0
Repayments of unsecured debt (Note 5)	(189,000)	0
Borrowings on unsecured revolving credit facility	70,000	305,000
Repayments on unsecured revolving credit facility	(10,000)	(305,000)
Principal payments on secured debt	(5,740)	(7,254)
Financing costs	(7,480)	(1,485)
Repurchase of common stock and restricted stock units	(12,986)	(6,874)
Proceeds from exercise of stock options	12,051	2,173
Contributions from noncontrolling interests in consolidated property partnerships	250	191,676
Distributions to noncontrolling interests in consolidated property partnerships	(12,234)	(1,139)
Dividends and distributions paid to common stockholders and common unitholders	(297,993)	(101,542)
Dividends and distributions paid to preferred stockholders and preferred unitholders (Note 7)	(7,409)	(9,938)
Net cash (used in) provided by financing activities	(101,729)	65,617
Net (decrease) increase in cash and cash equivalents and restricted cash	(5,899)	250,820
Cash and cash equivalents and restricted cash, beginning of period	250,129	57,204
Cash and cash equivalents and restricted cash, end of period	$ 244,230	$ 308,024

Consolidated Balance Sheets (KI

Consolidated Balance Sheets (KILROY REALTY, L.P.) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
REAL ESTATE ASSETS:
Land and improvements	$ 1,076,172	$ 1,108,971
Buildings and improvements	4,871,667	4,938,250
Undeveloped land and construction in progress	1,292,017	1,013,533
Total real estate assets held for investment	7,239,856	7,060,754
Accumulated depreciation and amortization	(1,216,358)	(1,139,853)
Total real estate assets held for investment, net	6,023,498	5,920,901
REAL ESTATE ASSETS AND OTHER ASSETS HELD FOR SALE, NET	0	9,417
CASH AND CASH EQUIVALENTS	64,954	193,418
RESTRICTED CASH (Note 2)	179,276	56,711
MARKETABLE SECURITIES (Note 11)	18,851	14,773
CURRENT RECEIVABLES, NET (Note 3)	18,626	13,460
DEFERRED RENT RECEIVABLES, NET (Note 3)	238,959	218,977
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET	185,420	208,368
PREPAID EXPENSES AND OTHER ASSETS, NET (Note 4)	108,715	70,608
TOTAL ASSETS	6,838,299	6,706,633
LIABILITIES:
Secured debt, net (Notes 5 and 11)	465,828	472,772
Unsecured debt, net (Notes 5 and 11)	1,909,381	1,847,351
Unsecured line of credit (Notes 5 and 11)	60,000	0
Accounts payable, accrued expenses and other liabilities	271,405	202,391
Accrued distributions (Note 16)	43,324	222,306
Deferred revenue and acquisition-related intangible liabilities, net	145,556	150,360
Rents received in advance and tenant security deposits	46,925	52,080
Liabilities of real estate assets held for sale	0	56
Total liabilities	2,942,419	2,947,316
COMMITMENTS AND CONTINGENCIES (Note 10)
Partners’ Capital (Note 8):
TOTAL LIABILITIES AND EQUITY (CAPITAL)	6,838,299	6,706,633
Kilroy Realty, L.P. [Member]
REAL ESTATE ASSETS:
Land and improvements	1,076,172	1,108,971
Buildings and improvements	4,871,667	4,938,250
Undeveloped land and construction in progress	1,292,017	1,013,533
Total real estate assets held for investment	7,239,856	7,060,754
Accumulated depreciation and amortization	(1,216,358)	(1,139,853)
Total real estate assets held for investment, net	6,023,498	5,920,901
REAL ESTATE ASSETS AND OTHER ASSETS HELD FOR SALE, NET	0	9,417
CASH AND CASH EQUIVALENTS	64,954	193,418
RESTRICTED CASH (Note 2)	179,276	56,711
MARKETABLE SECURITIES (Note 11)	18,851	14,773
CURRENT RECEIVABLES, NET (Note 3)	18,626	13,460
DEFERRED RENT RECEIVABLES, NET (Note 3)	238,959	218,977
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET	185,420	208,368
PREPAID EXPENSES AND OTHER ASSETS, NET (Note 4)	108,715	70,608
TOTAL ASSETS	6,838,299	6,706,633
LIABILITIES:
Secured debt, net (Notes 5 and 11)	465,828	472,772
Unsecured debt, net (Notes 5 and 11)	1,909,381	1,847,351
Unsecured line of credit (Notes 5 and 11)	60,000	0
Accounts payable, accrued expenses and other liabilities	271,405	202,391
Accrued distributions (Note 16)	43,324	222,306
Deferred revenue and acquisition-related intangible liabilities, net	145,556	150,360
Rents received in advance and tenant security deposits	46,925	52,080
Liabilities of real estate assets held for sale	0	56
Total liabilities	2,942,419	2,947,316
COMMITMENTS AND CONTINGENCIES (Note 10)
Partners’ Capital (Note 8):
Common units, 98,382,256 and 93,219,439 held by the general partner and 2,077,193 and 2,381,543 held by common limited partners issued and outstanding, respectively	3,763,078	3,431,768
Total partners’ capital	3,763,078	3,624,179
Noncontrolling interests in consolidated property partnerships and subsidiaries (Note 1)	132,802	135,138
Total capital	3,895,880	3,759,317
TOTAL LIABILITIES AND EQUITY (CAPITAL)	6,838,299	6,706,633
Kilroy Realty, L.P. [Member] | Series G Cumulative Redeemable Preferred Units [Member]
Partners’ Capital (Note 8):
Cumulative Redeemable Preferred units	0	96,155
Kilroy Realty, L.P. [Member] | Series H Cumulative Redeemable Preferred Units [Member]
Partners’ Capital (Note 8):
Cumulative Redeemable Preferred units	$ 0	$ 96,256

Consolidated Balance Sheets (K9

Consolidated Balance Sheets (KILROY REALTY, L.P.) (Parenthetical) - Kilroy Realty, L.P. [Member] - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Series G Cumulative Redeemable Preferred Units [Member]
Preferred units, issued	0	4,000,000
Preferred units, outstanding	0	4,000,000
Preferred stock dividend rate percentage	0.00%	6.875%
Preferred stock liquidation preference	$ 0	$ 100,000
Series H Cumulative Redeemable Preferred Units [Member]
Preferred units, issued	0	4,000,000
Preferred units, outstanding	0	4,000,000
Preferred stock dividend rate percentage	0.00%	6.375%
Preferred stock liquidation preference	$ 0	$ 100,000
Common Units [Member]
General partner, units issued	98,382,256	93,219,439
General partners, units outstanding	98,382,256	93,219,439
Limited partners, units issued	2,077,193	2,381,543
Noncontrolling common units of the Operating Partnership	2,077,193	2,381,543

Consolidated Statements of Op10

Consolidated Statements of Operations (KILROY REALTY, L.P.) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
REVENUES
Rental income	$ 159,954	$ 146,539	$ 475,527	$ 423,947
Tenant reimbursements	19,665	16,406	58,228	43,948
Other property income	1,915	5,403	7,685	6,032
Total revenues	181,534	168,348	541,440	473,927
EXPENSES
Property expenses	33,070	30,050	97,615	85,236
Real estate taxes	16,371	14,501	50,878	39,378
Provision for bad debts	1,036	0	2,743	0
Ground leases	1,562	909	4,751	2,506
General and administrative expenses	14,514	13,533	43,750	40,949
Acquisition-related expenses (Note 1)	0	188	0	964
Depreciation and amortization	62,567	56,666	185,737	160,452
Total expenses	129,120	115,847	385,474	329,485
OTHER (EXPENSES) INCOME
Interest income and other net investment gains (Note 11)	1,526	538	3,629	1,120
Interest expense (Note 5)	(16,151)	(14,976)	(51,476)	(41,189)
Total other (expenses) income	(14,625)	(14,438)	(47,847)	(40,069)
Net gain (loss) on sale of land (Note 2)	449	0	449	(295)
Gains on sales of depreciable operating properties (Note 2)	37,250	18,312	39,507	164,302
NET INCOME	75,488	56,375	148,075	268,380
Net income attributable to noncontrolling interests in consolidated property partnerships and subsidiaries	(4,378)	(2,480)	(11,992)	(7,330)
NET INCOME ATTRIBUTABLE TO KILROY REALTY CORPORATION (KILROY REALTY, L.P.)	71,110	53,895	136,083	261,050
Original issuance costs of redeemed preferred stock (preferred units)	(3,744)	0	(7,589)	0
Total preferred distributions	(4,552)	(3,313)	(13,363)	(9,938)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS (UNITHOLDERS)	$ 66,558	$ 50,582	$ 122,720	$ 251,112
Net income available to common unitholders per unit-basic (in dollars per unit) (Note 13)	$ 0.67	$ 0.54	$ 1.24	$ 2.71
Net income available to common unitholders per unit-diluted (in dollars per unit) (Note 13)	$ 0.67	$ 0.54	$ 1.23	$ 2.69
Weighted average common units outstanding - basic (in units) (Note 13)	98,352,139	92,227,016	98,008,780	92,220,522
Weighted average common units outstanding - diluted (in units) (Note 13)	98,911,612	92,920,406	98,591,048	92,831,538
Kilroy Realty, L.P. [Member]
REVENUES
Rental income	$ 159,954	$ 146,539	$ 475,527	$ 423,947
Tenant reimbursements	19,665	16,406	58,228	43,948
Other property income	1,915	5,403	7,685	6,032
Total revenues	181,534	168,348	541,440	473,927
EXPENSES
Property expenses	33,070	30,050	97,615	85,236
Real estate taxes	16,371	14,501	50,878	39,378
Provision for bad debts	1,036	0	2,743	0
Ground leases	1,562	909	4,751	2,506
General and administrative expenses	14,514	13,533	43,750	40,949
Acquisition-related expenses (Note 1)	0	188	0	964
Depreciation and amortization	62,567	56,666	185,737	160,452
Total expenses	129,120	115,847	385,474	329,485
OTHER (EXPENSES) INCOME
Interest income and other net investment gains (Note 11)	1,526	538	3,629	1,120
Interest expense (Note 5)	(16,151)	(14,976)	(51,476)	(41,189)
Total other (expenses) income	(14,625)	(14,438)	(47,847)	(40,069)
INCOME FROM OPERATIONS BEFORE GAINS (LOSS) ON SALES OF REAL ESTATE	37,789	38,063	108,119	104,373
Net gain (loss) on sale of land (Note 2)	449	0	449	(295)
Gains on sales of depreciable operating properties (Note 2)	37,250	18,312	39,507	164,302
NET INCOME	75,488	56,375	148,075	268,380
Net income attributable to noncontrolling interests in consolidated property partnerships and subsidiaries	(3,086)	(1,121)	(9,648)	(1,703)
NET INCOME ATTRIBUTABLE TO KILROY REALTY CORPORATION (KILROY REALTY, L.P.)	72,402	55,254	138,427	266,677
Preferred distributions	(808)	(3,313)	(5,774)	(9,938)
Original issuance costs of redeemed preferred stock (preferred units)	(3,744)	0	(7,589)	0
Total preferred distributions	(4,552)	(3,313)	(13,363)	(9,938)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS (UNITHOLDERS)	$ 67,850	$ 51,941	$ 125,064	$ 256,739
Net income available to common unitholders per unit-basic (in dollars per unit) (Note 13)	$ 0.67	$ 0.54	$ 1.23	$ 2.70
Net income available to common unitholders per unit-diluted (in dollars per unit) (Note 13)	$ 0.67	$ 0.54	$ 1.23	$ 2.68
Weighted average common units outstanding - basic (in units) (Note 13)	100,429,332	94,858,292	100,160,595	94,630,183
Weighted average common units outstanding - diluted (in units) (Note 13)	100,988,805	95,551,682	100,742,863	95,241,199
Dividends declared per common unit (in dollars per unit)	$ 0.425	$ 0.375	$ 1.225	$ 1.1000

Consolidated Statements of Capi

Consolidated Statements of Capital (KILROY REALTY, L.P.) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 75,488	$ 56,375	$ 148,075	$ 268,380
Redemption of Series G and H Preferred units (Note 8)			(200,000)
Original issuance costs of redeemed preferred stock (preferred units)	(3,744)	0	(7,589)	0
Non-cash amortization of share-based compensation			19,013	19,303
Settlement of restricted stock units			0	0
Contributions from noncontrolling interests in consolidated property partnerships			250	191,676
Distributions to noncontrolling interests in consolidated property partnerships			(12,234)	(1,139)
Preferred distributions			(5,774)	(9,938)
Noncontrolling Interests [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			11,992	7,330
Contributions from noncontrolling interests in consolidated property partnerships			250	78,654
Distributions to noncontrolling interests in consolidated property partnerships			(12,234)	(1,139)
Kilroy Realty, L.P. [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			3,759,317	3,234,586
Net income	75,488	56,375	148,075	268,380
Redemption of Series G and H Preferred units (Note 8)			(200,000)
Original issuance costs of redeemed preferred stock (preferred units)	(3,744)	0	(7,589)	0
Issuance of common units (Note 8)			308,812
Issuance of common units in connection with acquisition				48,033
Issuance of share-based compensation awards			5,291	1,339
Non-cash amortization of share-based compensation			19,013	19,303
Exercise of stock options (Note 9)			12,051	2,173
Repurchase of common units, stock options and restricted stock units			(12,986)	(6,874)
Settlement of restricted stock units			0	0
Contributions from noncontrolling interests in consolidated property partnerships			250	191,676
Distributions to noncontrolling interests in consolidated property partnerships			(12,234)	(1,139)
Preferred distributions			(5,774)	(9,938)
Distributions declared per common unit ($1.225 and $1.10 per unit for the nine months ended September 2017 and 2016, respectively)			(125,935)	(105,637)
Ending balance	3,895,880	3,641,902	3,895,880	3,641,902
Kilroy Realty, L.P. [Member] | Partners Capital Preferred Units [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			192,411	192,411
Redemption of Series G and H Preferred units (Note 8)			192,411
Ending balance	0	192,411	0	192,411
Kilroy Realty, L.P. [Member] | Partners Capital Common Unit [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 3,431,768	$ 3,031,609
Beginning balance (in units)			95,600,982	94,023,465
Net income			$ 138,427	$ 266,677
Original issuance costs of redeemed preferred stock (preferred units)			$ (7,589)
Issuance of common units (in units) (Note 8)			4,427,500
Issuance of common units (Note 8)			$ 308,812
Issuance of common units in connection with acquisition (in units)				867,701
Issuance of common units in connection with acquisition				$ 48,033
Issuance of share-based compensation awards			5,291	1,339
Non-cash amortization of share-based compensation			$ 19,013	$ 19,303
Exercise of stock options (Note 9) (in units)			282,000	51,000
Exercise of stock options (Note 9)			$ 12,051	$ 2,173
Repurchase of common units and restricted stock units (in units)			(168,881)	(110,528)
Repurchase of common units, stock options and restricted stock units			$ (12,986)	$ (6,874)
Settlement of restricted stock units (in units)			317,848	72,130
Settlement of restricted stock units			$ 0	$ 0
Contributions from noncontrolling interests in consolidated property partnerships				113,022
Preferred distributions			(5,774)	(9,938)
Distributions declared per common unit ($1.225 and $1.10 per unit for the nine months ended September 2017 and 2016, respectively)			(125,935)	(105,637)
Ending balance	$ 3,763,078	$ 3,359,707	$ 3,763,078	$ 3,359,707
Ending balance (in units)	100,459,449	94,903,768	100,459,449	94,903,768
Kilroy Realty, L.P. [Member] | Total Partners Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 3,624,179	$ 3,224,020
Net income			138,427	266,677
Redemption of Series G and H Preferred units (Note 8)			(200,000)
Issuance of common units (Note 8)			308,812
Issuance of common units in connection with acquisition				48,033
Issuance of share-based compensation awards			5,291	1,339
Non-cash amortization of share-based compensation			19,013	19,303
Exercise of stock options (Note 9)			12,051	2,173
Repurchase of common units, stock options and restricted stock units			(12,986)	(6,874)
Settlement of restricted stock units			0	0
Contributions from noncontrolling interests in consolidated property partnerships				113,022
Preferred distributions			(5,774)	(9,938)
Distributions declared per common unit ($1.225 and $1.10 per unit for the nine months ended September 2017 and 2016, respectively)			(125,935)	(105,637)
Ending balance	$ 3,763,078	$ 3,552,118	3,763,078	3,552,118
Kilroy Realty, L.P. [Member] | Noncontrolling Interests [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			135,138	10,566
Net income			9,648	1,703
Contributions from noncontrolling interests in consolidated property partnerships			250	78,654
Distributions to noncontrolling interests in consolidated property partnerships			(12,234)	(1,139)
Ending balance	$ 132,802	$ 89,784	$ 132,802	$ 89,784

Consolidated Statements of Ca12

Consolidated Statements of Capital (KILROY REALTY, L.P.) (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Kilroy Realty, L.P. [Member]
Dividends declared per common unit (in dollars per unit)	$ 0.425	$ 0.375	$ 1.225	$ 1.1000

Consolidated Statements of Ca13

Consolidated Statements of Cash Flows (KILROY REALTY, L.P.) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 148,075	$ 268,380
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of real estate assets and leasing costs	181,875	157,587
Depreciation of non-real estate furniture, fixtures and equipment	3,862	2,865
Increase in provision for bad debts	2,743	0
Non-cash amortization of share-based compensation awards	13,617	15,263
Non-cash amortization of deferred financing costs and debt discounts and premiums	2,398	2,020
Non-cash amortization of net below market rents	(6,026)	(5,128)
Gains on sales of depreciable operating properties (Note 2)	(39,507)	(164,302)
(Gain) loss on sale of land (Note 2)	(449)	295
Non-cash amortization of deferred revenue related to tenant-funded tenant improvements	(12,394)	(9,700)
Straight-line rents	(25,537)	(22,856)
Net change in other operating assets	(16,970)	(7,263)
Net change in other operating liabilities	24,855	15,444
Net cash provided by operating activities	276,542	252,605
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for development properties and undeveloped land	(270,839)	(222,719)
Expenditures for operating properties and other capital assets	(61,875)	(81,688)
Net proceeds received from dispositions (Note 2)	182,492	325,031
(Increase) decrease in acquisition-related deposits	(30,490)	1,902
Expenditures for acquisition of operating properties	0	(55,415)
Expenditures for acquisition of undeveloped land	0	(33,513)
Increase in note receivable	0	(1,000)
Net cash used in investing activities	(180,712)	(67,402)
CASH FLOWS FROM FINANCING ACTIVITIES:
Redemption of Series G and H Preferred units (Note 8)	(200,000)	0
Proceeds from the issuance of unsecured debt (Note 5)	250,000	0
Repayments of unsecured debt (Note 5)	(189,000)	0
Borrowings on unsecured revolving credit facility	70,000	305,000
Repayments on unsecured revolving credit facility	(10,000)	(305,000)
Principal payments on secured debt	(5,740)	(7,254)
Financing costs	(7,480)	(1,485)
Repurchase of common stock and restricted stock units	(12,986)	(6,874)
Proceeds from exercise of stock options	12,051	2,173
Contributions from noncontrolling interests in consolidated property partnerships	250	191,676
Distributions to noncontrolling interests in consolidated property partnerships	(12,234)	(1,139)
Distributions paid to common unitholders	(297,993)	(101,542)
Distributions paid to preferred unitholders (Note 8)	(7,409)	(9,938)
Net cash (used in) provided by financing activities	(101,729)	65,617
Net (decrease) increase in cash and cash equivalents and restricted cash	(5,899)	250,820
Cash and cash equivalents and restricted cash, beginning of period	250,129	57,204
Cash and cash equivalents and restricted cash, end of period	244,230	308,024
Kilroy Realty, L.P. [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	148,075	268,380
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of real estate assets and leasing costs	181,875	157,587
Depreciation of non-real estate furniture, fixtures and equipment	3,862	2,865
Increase in provision for bad debts	2,743	0
Non-cash amortization of share-based compensation awards	13,617	15,263
Non-cash amortization of deferred financing costs and debt discounts and premiums	2,398	2,020
Non-cash amortization of net below market rents	(6,026)	(5,128)
Gains on sales of depreciable operating properties (Note 2)	(39,507)	(164,302)
(Gain) loss on sale of land (Note 2)	(449)	295
Non-cash amortization of deferred revenue related to tenant-funded tenant improvements	(12,394)	(9,700)
Straight-line rents	(25,537)	(22,856)
Net change in other operating assets	(16,970)	(7,263)
Net change in other operating liabilities	24,855	15,444
Net cash provided by operating activities	276,542	252,605
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for development properties and undeveloped land	(270,839)	(222,719)
Expenditures for operating properties and other capital assets	(61,875)	(81,688)
Net proceeds received from dispositions (Note 2)	182,492	325,031
(Increase) decrease in acquisition-related deposits	(30,490)	1,902
Expenditures for acquisition of operating properties	0	(55,415)
Expenditures for acquisition of undeveloped land	0	(33,513)
Increase in note receivable	0	(1,000)
Net cash used in investing activities	(180,712)	(67,402)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of common units (Note 8)	308,812	0
Redemption of Series G and H Preferred units (Note 8)	(200,000)	0
Proceeds from the issuance of unsecured debt (Note 5)	250,000	0
Repayments of unsecured debt (Note 5)	(189,000)	0
Borrowings on unsecured revolving credit facility	70,000	305,000
Repayments on unsecured revolving credit facility	(10,000)	(305,000)
Principal payments on secured debt	(5,740)	(7,254)
Financing costs	(7,480)	(1,485)
Repurchase of common stock and restricted stock units	(12,986)	(6,874)
Proceeds from exercise of stock options	12,051	2,173
Contributions from noncontrolling interests in consolidated property partnerships	250	191,676
Distributions to noncontrolling interests in consolidated property partnerships	(12,234)	(1,139)
Distributions paid to common unitholders	(297,993)	(101,542)
Distributions paid to preferred unitholders (Note 8)	(7,409)	(9,938)
Net cash (used in) provided by financing activities	(101,729)	65,617
Net (decrease) increase in cash and cash equivalents and restricted cash	(5,899)	250,820
Cash and cash equivalents and restricted cash, beginning of period	250,129	57,204
Cash and cash equivalents and restricted cash, end of period	$ 244,230	$ 308,024

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2017
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 and mixed-use 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 properties at September 30, 2017 : Number of Buildings Rentable Square Feet (unaudited) Number of Tenants Percentage Occupied (unaudited) Percentage Leased (unaudited) Stabilized Office Properties 101 13,720,598 515 94.0 % 96.2 % Number of Number of Units Percentage Occupied (unaudited) Percentage Leased (unaudited) Stabilized Residential Property 1 200 72.0 % 74.5 % Our stabilized portfolio includes all of our properties with the exception of development and redevelopment properties currently under construction or committed for construction, “lease-up” properties, real estate assets held for sale and undeveloped land. 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 office 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” or held for sale as of September 30, 2017 . During the nine months ended September 30, 2017 , we added one development project to our stabilized office portfolio consisting of 365,359 rentable square feet in Hollywood, California. As of September 30, 2017 , the following properties were excluded from our stabilized portfolio. We did not have any redevelopment properties at September 30, 2017 . Number of Properties/Projects Estimated Rentable Square Feet (1) Development projects under construction (2) 4 1,800,000 ________________________ (1) Estimated rentable square feet upon completion. (2) Development projects under construction also include 96,000 square feet of retail space and 237 residential units in addition to the estimated office rentable square feet noted above. Our stabilized portfolio also excludes our near-term and future development pipeline, which as of September 30, 2017 was comprised of five development sites, representing approximately 47 gross acres of undeveloped land. As of September 30, 2017 , all of our properties and development projects were owned and all of our business was conducted in the state of California with the exception of twelve office properties and one development project under construction located in the state of Washington. All of our properties and development projects are 100% owned, excluding four office properties owned by three consolidated property partnerships. Two of the three property partnerships, 100 First Street Member, LLC (“100 First LLC”) and 303 Second Street Member, LLC (“303 Second LLC”), each owned one office property in San Francisco, California through subsidiary REITs. As of September 30, 2017 , the Company owned a 56% common equity interest in both 100 First LLC and 303 Second LLC. The third property partnership, Redwood City Partners, LLC (“Redwood LLC”) owned two office properties in Redwood City, California. As of September 30, 2017 , the Company owned an approximate 93% common equity interest in Redwood LLC. The remaining interests in all three property partnerships were owned by unrelated third parties. Ownership and 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, Kilroy Services, LLC (“KSLLC”), 100 First LLC, 303 Second LLC, Redwood 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, 100 First LLC, 303 Second LLC, Redwood 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. As of September 30, 2017 , the Company owned an approximate 97.9% common general partnership interest in the Operating Partnership. The remaining approximate 2.1% common limited partnership interest in the Operating Partnership as of September 30, 2017 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.” 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. We conduct substantially all of our development activities through KSLLC, which is a wholly owned subsidiary of the Operating Partnership. With the exception of the Operating Partnership and our consolidated property partnerships, all of our subsidiaries are wholly-owned. 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, 2017 . 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 for the year ended December 31, 2016 . Variable Interest Entities The Operating Partnership is a variable interest entity (“VIE”) of the Company as the Operating Partnership is a limited partnership in which the common limited partners do not have substantive kick-out or participating rights. At September 30, 2017 , the consolidated financial statements of the Company included two VIEs in addition to the Operating Partnership: 100 First LLC and 303 Second LLC. At September 30, 2017 , the Company and the Operating Partnership were determined to be the primary beneficiaries of these two VIEs since we had the ability to control the activities that most significantly impact each of the VIE’s economic performance. As of September 30, 2017 , these two VIEs’ total assets, liabilities and noncontrolling interests included on our consolidated balance sheet were approximately $429.4 million (of which $383.7 million related to real estate held for investment), approximately $151.4 million and approximately $121.8 million , respectively. Revenues, income and net assets generated by 100 First LLC and 303 Second LLC may only be used to settle its contractual obligations, which primarily consist of operating expenses, capital expenditures and required distributions. At December 31, 2016 , the consolidated financial statements of the Company and the Operating Partnership included three VIEs in which we were deemed to be the primary beneficiary: 100 First LLC, 303 Second LLC and an entity established during the fourth quarter of 2016 to facilitate a transaction intended to qualify as a like-kind exchange pursuant to Section 1031 of the Code (“Section 1031 Exchange”). In January 2017, the Section 1031 Exchange was successfully completed and the entity established for the 1031 Exchange was no longer a VIE. At December 31, 2016 , the impact of consolidating the VIEs increased the Company’s total assets, liabilities and noncontrolling interests on our consolidated balance sheet by approximately $654.3 million (of which $588.6 million related to real estate held for investment), approximately $166.1 million and approximately $124.3 million , respectively. Adoption of New Accounting Pronouncements Effective January 1, 2017, the Company adopted FASB ASU No. 2017-01 (“ASU 2017-01”) which clarifies the framework for determining whether an integrated set of assets and activities meets the definition of a business. The revised framework provides a screen for determining whether an integrated set of assets is a business combination or an asset acquisition and clarifies that when substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar assets, the set of assets and activities is deemed not to meet the definition of a business. As a result of our adoption of the guidance, which we adopted on a prospective basis, the Company expects that most of our future acquisitions of operating properties and development properties that were previously accounted for as business combinations will instead be accounted for as asset acquisitions under the new guidance. In addition, we expect that most of the transaction costs associated with these future acquisitions will be capitalized as part of the purchase price of the acquisition instead of being expensed as incurred to acquisition-related expenses. The Company did not have any acquisitions of operating properties during the nine months ended September 30, 2017 . Also effective January 1, 2017, the Company adopted ASU No. 2016-18 (“ASU 2016-18”) which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. The Company adopted ASU 2016-18 on a retrospective basis. Therefore, amounts generally described as restricted cash and restricted cash equivalents are included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the Company’s consolidated statements of cash flows for the nine months ended September 30, 2017 and 2016 . As a result of the adoption of ASU 2016-18, the change in restricted cash is no longer presented as a separate line item within cash flows from investing activities on the Company’s consolidated statements of cash flows since such balances are now included in total cash at both the beginning and end of the reporting period. As a result, for the nine months ended September 30, 2016 , the Company had net cash used in investing activities of $67.4 million instead of net cash used in investing activities of $124.2 million as previously reported since the Company had an increase in restricted cash of $56.8 million during the nine months ended September 30, 2016 primarily due to $48.4 million of restricted cash that was held at qualified intermediaries to facilitate potential future Section1031 Exchanges. In addition, effective January 1, 2017, the Company adopted ASU No. 2016-09 (“ASU 2016-09”) which simplified several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The adoption of this guidance did not have an impact on our consolidated financial statements or notes to our consolidated financial statements. Recently Issued Accounting Pronouncements ASU No. 2016-02 “Leases (Topic 842)” On February 25, 2016, the FASB issued ASU No. 2016-02 (“ASU 2016-02”) to amend the accounting guidance for leases. The accounting applied by a lessor is largely unchanged under ASU 2016-02. However, the standard requires lessees to recognize lease assets and lease liabilities for leases classified as operating leases on the balance sheet. Lessees will recognize in the statement of financial position a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. If a lessee makes this election, it will recognize lease expense for such leases generally on a straight-line basis over the lease term. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 and early adoption is permitted. We are currently conducting our evaluation of the impact of the guidance on our consolidated financial statements and have an active project team working on the evaluation and implementation of the guidance. We currently believe that the adoption of the standard will not significantly change the accounting for operating leases on our consolidated balance sheets where we are the lessor, and that such leases will be accounted for in a similar method to existing standards with the underlying leased asset being reported and recognized as a real estate asset. We currently expect that certain non-lease components will need to be accounted for separately from the lease components, with the lease components continuing to be recognized on a straight-line basis over the term of the lease and certain non-lease components (such as common area maintenance) being accounted for under the new revenue recognition guidance in ASU 2014-09 discussed below, even when revenue for such non-lease components is not separately stipulated in the lease. In addition, under ASU 2016-02, lessors will only be permitted to capitalize and amortize incremental direct leasing costs. As a result, we expect that upon the adoption of the standard, we will no longer be able to capitalize and amortize certain leasing related costs and instead will expense these costs as incurred. We currently expect this could have a material impact to the Company’s results of operations upon adoption of the standard. For leases where we are the lessee, specifically for our ground leases, we currently believe that the adoption of the standard will significantly change the accounting on our consolidated balance sheets since both existing ground leases and any future ground leases will be required to be recorded on the Company’s consolidated balance sheets as an obligation of the Company. We currently believe that existing ground leases executed before the January 1, 2019 adoption date will continue to be accounted for as operating leases and will not have a material impact on our recognition of ground lease expense or our results of operations. However, we believe that we will be required to recognize a right of use asset and a lease liability on our consolidated balance sheets equal to the present value of the minimum lease payments required in accordance with each ground lease. As of September 30, 2017 , our future undiscounted minimum rental payments under these leases totaled $252.8 million , with several of the leases containing provisions for rental payments to fluctuate based on fair market value and operating income measurements with expirations through 2093. In addition, we currently believe that for new ground leases entered into after the adoption date of the new standard, such leases could be required to be accounted for as a financing type lease, resulting in ground lease expense recorded using the effective interest method instead of on a straight-line basis over the term of the lease. This could have a significant impact on our results of operations if we enter into material new ground leases after the date of adoption since ground lease expense calculated using the effective interest method results in an increased amount of ground lease expense in the earlier years of a ground lease as compared to the current straight-line method. We will adopt the guidance on a modified retrospective basis as required by ASU 2016-02. We are in the process of evaluating whether we will elect to apply the practical expedients identified in the standard but currently believe that we may do so. ASU No. 2014-09 “ Revenue From Contracts with Customers (Topic 606)” In May 2014, the FASB issued ASU 2014-09 “Revenue From Contracts with Customers (Topic 606)” (“ASU 2014-09”). The objective of ASU 2014-09 is to establish a single comprehensive model for entities to use in accounting for revenue from contracts with customers and will supersede most of the existing revenue recognition guidance. On May 9, 2016 and December 21, 2016, the FASB issued ASU No. 2016-12 and ASU No. 2016-20, which provides practical expedients, technical corrections, and improvements for certain aspects of ASU No. 2014-09. Public business entities may elect to adopt the amendments as of the original effective date; however, adoption is required for annual reporting periods beginning after December 15, 2017. We have compiled an inventory of the sources of revenue that will be impacted by ASU 2014-09. Specifically, we have evaluated the impact of the guidance on timing of gain recognition for dispositions and currently do not believe there will be a material impact to our consolidated financial statements given the simplicity of the Company’s historical disposition transactions. In addition, we currently believe that certain non-lease components of revenue from leases such as common area maintenance and certain types of parking revenue may be impacted by ASU 2014-09 when we adopt ASU 2016-02 on January 1, 2019. We are in the process of evaluating the impact on these non-lease revenue components and currently believe the impact will be limited to the income statement presentation of revenue and not the total amount of revenue recognized. Other Recently Issued Pronouncements On May 10, 2017, the FASB issued ASU No. 2017-09 “Compensation - Stock Compensation (Topic 718)” to clarify the scope of modification accounting. Under the guidance, an entity will not apply modification accounting to a share-based payment award if the award’s fair value, vesting conditions, and classification as an equity or liability instrument remain the same immediately before and after the change. The guidance is effective for annual periods beginning after December 15, 2017 and early adoption is permitted. The Company does not currently anticipate that the guidance will have a material impact on our consolidated financial statements or notes to our consolidated financial statements. On February 22, 2017, the FASB issued ASU No. 2017-05 “Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20)” (“ASU 2017-05”) to provide guidance and clarify the scope of the original guidance within Subtopic 610-20 “Gains and Losses from the Derecognition of Nonfinancial Assets” that was issued in connection with ASU 2014-09, which provided guidance for recognizing gains and losses from the transfer of nonfinancial assets in transactions with noncustomers. ASU 2017-05 additionally adds guidance pertaining to the partial sales of real estate and clarifies that nonfinancial assets within the scope of Accounting Standards Codification Subtopic 610-20 may include nonfinancial assets transferred within a legal entity to a counterparty. For example, a parent may transfer control of nonfinancial assets by transferring ownership interests in a consolidated subsidiary. ASU 2017-05 is effective for fiscal years beginning after December 15, 2017, with early application permitted for fiscal years beginning after December 15, 2016. We are currently evaluating the impact of ASU 2017-05 on our consolidated financial statements and currently do not anticipate that the guidance will have a material impact on our consolidated financial statements or notes to our consolidated financial statements. On August 26, 2016, the FASB issued ASU No. 2016-15 (“ASU 2016-15”) to provide guidance for areas where there is diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. ASU 2016-15 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company does not currently anticipate that the guidance will have a material impact on our consolidated financial statements or notes to our consolidated financial statements. On June 16, 2016, the FASB issued ASU No. 2016-13 (“ASU 2016-13”) to amend the accounting for credit losses for certain financial instruments. Under the new guidance, an entity recognizes its estimate of expected credit losses as an allowance, which the FASB believes will result in more timely recognition of such losses. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company does not currently anticipate that the guidance will have a material impact on our consolidated financial statements or notes to our consolidated financial statements. On January 5, 2016, the FASB issued ASU No. 2016-01 (“ASU 2016-01”) to amend the accounting guidance on the classification and measurement of financial instruments. The standard requires that all investments in equity securities, including other ownership interests, are carried at fair value through net income. This requirement does not apply to investments that qualify for equity method accounting or to those that result in consolidation of the investee or for which the entity has elected the predictability exception to fair value measurement. Additionally, the standard requires that the portion of the total fair value change caused by a change in instrument-specific credit risk for financial liabilities for which the fair value option has been elected would be recognized in other comprehensive income. Any accumulated amount remaining in other comprehensive income is reclassified to earnings when the liability is extinguished. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017. The Company does not currently anticipate that the guidance will have a material impact on our consolidated financial statements or notes to our consolidated financial statements.

Dispositions

Dispositions	9 Months Ended
	Sep. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Dispositions	Dispositions The following table summarizes the properties sold during the nine months ended September 30, 2017 . Location Property Type Month of Disposition Number of Buildings Rentable Square Feet Sales Price (1) (in millions) 5717 Pacific Center Boulevard, San Diego, CA (2) Office January 1 67,995 $ 12.1 Sorrento Mesa and Mission Valley Properties (3) Office September 10 675,143 174.5 Total Dispositions 11 743,138 $ 186.6 ________________________ (1) Represents gross sales price before the impact of broker commissions and closing costs. (2) This property was classified as held for sale at December 31, 2016 . (3) The Sorrento Mesa and Mission Valley Properties includes the following properties: 10390, 10394, 10398, 10421, 10445 and 10455 Pacific Center Court, 2355, 2365, 2375 and 2385 Northside Drive and Pacific Corporate Center - Lot 8, a 5.0 acre undeveloped land parcel. The total gain on the operating properties and land sold during the nine months ended September 30, 2017 was $39.5 million and $0.4 million , respectively. As of September 30, 2017 , approximately $170.6 million of net proceeds related to the Sorrento Mesa and Mission Valley Properties disposition were temporarily being held at qualified intermediaries, at our direction, for the purpose of facilitating potential future Section 1031 Exchanges. The cash proceeds are included in restricted cash on our consolidated balance sheets as of September 30, 2017 .

Receivables

Receivables	9 Months Ended
	Sep. 30, 2017
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, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 (in thousands) Current receivables $ 20,746 $ 15,172 Allowance for uncollectible tenant receivables (2,120 ) (1,712 ) Current receivables, net $ 18,626 $ 13,460 Deferred Rent Receivables, net Deferred rent receivables, net consisted of the following as of September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 (in thousands) Deferred rent receivables $ 241,929 $ 220,501 Allowance for deferred rent receivables (2,970 ) (1,524 ) Deferred rent receivables, net $ 238,959 $ 218,977

Prepaid Expenses and Other Asse

Prepaid Expenses and Other Assets, Net	9 Months Ended
	Sep. 30, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Assets, Net	Prepaid Expenses and Other Assets, Net Prepaid expenses and other assets, net consisted of the following at September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 (in thousands) Furniture, fixtures and other long-lived assets, net $ 39,889 $ 40,395 Notes receivable (1) 19,838 19,439 Prepaid expenses & acquisition deposits 48,988 10,774 Total prepaid expenses and other assets, net $ 108,715 $ 70,608 _______________ (1) Approximately $15.1 million of our notes receivable are secured by real estate.

Secured and Unsecured Debt of t

Secured and Unsecured Debt of the Operating Partnership	9 Months Ended
	Sep. 30, 2017
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 Unsecured Senior Notes - Private Placement On February 17, 2017, the Operating Partnership issued the $175.0 million principal amount of its 3.35% Senior Notes, Series A, due February 17, 2027 (the “Series A Notes”), and the $75.0 million principal amount of its 3.45% Senior Notes, Series B, due February 17, 2029 (the “Series B Notes” and, together with the Series A Notes, the “Series A and B Notes”). The Series A and B Notes were issued pursuant to a delayed draw option under a Note Purchase Agreement entered into in connection with a private placement in September 2016. As of September 30, 2017 , there was $175.0 million and $75.0 million issued and outstanding aggregate principal amount of Series A and B Notes, respectively. The Series A Notes mature on February 17, 2027, and the Series B Notes mature on February 17, 2029, unless earlier redeemed or prepaid pursuant to the terms of the Note Purchase Agreement. Interest on the Series A and B Notes is payable semi-annually in arrears on February 17 and August 17 of each year. The Operating Partnership may, at its option and upon notice to the purchasers of the Series A and B Notes, prepay at any time all, or from time to time, any part of the Series A and B Notes then outstanding (in an amount not less than 5% of the aggregate principal amount of the Series A and B Notes then outstanding in the case of a partial prepayment), at 100% of the principal amount so prepaid, plus the make-whole amount determined for the prepayment date with respect to such principal amount as set forth in the Note Purchase Agreement. In connection with the issuance of the Series A and B Notes, the Company entered into an agreement whereby it guarantees the payment by the Operating Partnership of all amounts due with respect to the Series A and B Notes and the performance by the Operating Partnership of its obligations under the Note Purchase Agreement. Unsecured Revolving Credit Facility and Term Loan Facility In July 2017, the Operating Partnership amended and restated the terms of its unsecured revolving credit facility and unsecured term loan facility (together, the “Facility”). The amendment and restatement increased the size of the unsecured revolving credit facility from $600.0 million to $750.0 million , maintained the size of the unsecured term loan facility of $150.0 million , reduced the borrowing costs and extended the maturity date of the Facility to July 2022. The unsecured term loan facility features two six-month delayed draw options. The following table summarizes the balance and terms of our unsecured revolving credit facility as of September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 (in thousands) Outstanding borrowings $ 60,000 $ — Remaining borrowing capacity 690,000 600,000 Total borrowing capacity (1) $ 750,000 $ 600,000 Interest rate (2) 2.24 % 1.82 % Facility fee-annual rate (3) 0.200% Maturity date July 2022 July 2019 ________________________ (1) We may elect to borrow, subject to bank approval and obtaining commitments for any additional borrowing capacity, up to an additional $600.0 million under an accordion feature under the terms of the unsecured revolving credit facility and unsecured term loan facility. (2) Our unsecured revolving credit facility interest rate was calculated based on an annual rate of LIBOR plus 1.000% and LIBOR plus 1.050% as of September 30, 2017 and December 31, 2016 , respectively. (3) Our facility fee is paid on a quarterly basis and is calculated based on the total borrowing capacity. In addition to the facility fee, we incurred debt origination and legal costs. As of September 30, 2017 and December 31, 2016 , $6.3 million and $3.3 million of unamortized deferred financing costs, respectively, remained to be amortized through the maturity date of our unsecured revolving credit facility, which are included in prepaid expenses and other assets, net on our consolidated balance sheets. The Company intends to borrow under the unsecured revolving credit facility from time to time for general corporate purposes, to finance development and redevelopment expenditures, to fund potential acquisitions and to potentially repay long-term debt. The following table summarizes the balance and terms of our unsecured term loan facility as of September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 (in thousands) Outstanding borrowings (1) $ — $ 150,000 Remaining borrowing capacity 150,000 — Total borrowing capacity (2) $ 150,000 $ 150,000 Interest rate (3) 2.33 % 1.85 % Undrawn facility fee-annual rate (4) 0.200 % — % Maturity date July 2022 July 2019 ________________________ (1) In July 2017, the unsecured term loan facility was paid down and the Facility was amended to include two, six-month delayed draw options on the unsecured term loan facility. The Company may draw on the unsecured term loan facility through July 2018, at which time the outstanding balance will become the balance of the unsecured term loan facility and no additional draws may be made. However, if the Company does not draw at least $75.0 million by the end of first option term in January 2018, the total borrowing capacity under the Facility will be reduced by 50% of the unutilized borrowing capacity at that time. The Company intends to draw $75.0 million prior to the end of the first option term in January 2018. (2) As of September 30, 2017 and December 31, 2016 , $1.2 million and $0.7 million of unamortized deferred financing costs, respectively, remained to be amortized through the maturity date of our unsecured term loan facility. (3) Our unsecured term loan facility interest rate was calculated based on an annual rate of LIBOR plus 1.100% and LIBOR plus 1.150% as of September 30, 2017 and December 31, 2016 , respectively. (4) In July 2017, the Facility was amended to include a facility fee on the remaining borrowing capacity of the unsecured term loan facility, which is paid on a monthly basis. Additionally, as of December 31, 2016 the Operating Partnership had a $39.0 million unsecured term loan outstanding with an annual interest rate of LIBOR plus 1.150% that was to mature in July 2019. As of December 31, 2016 , $0.2 million of unamortized deferred financing costs remained to be amortized through the maturity date of our unsecured term loan. Concurrently with the amendment of the Facility, the Operating Partnership repaid its $39.0 million unsecured term loan. Debt Covenants and Restrictions The unsecured revolving credit facility, the unsecured term loan facility, the unsecured term loan, the unsecured senior notes, the Series A and B 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, 2017 . Debt Maturities The following table summarizes the stated debt maturities and scheduled amortization payments of our issued and outstanding debt, excluding unamortized debt discounts, premiums and deferred financing costs, as of September 30, 2017 : Year (in thousands) Remaining 2017 $ 1,545 2018 451,669 2019 76,309 2020 255,137 2021 5,342 Thereafter 1,659,023 Total (1) $ 2,449,025 ________________________ (1) Includes gross principal balance of outstanding debt before the effect of the following at September 30, 2017 : $10.9 million of unamortized deferred financing costs, $6.0 million of unamortized discounts for the unsecured senior notes and $3.0 million of unamortized premiums for the secured debt. Capitalized Interest and Loan Fees The following table sets forth gross interest expense, including debt discount/premium and deferred financing cost amortization, net of capitalized interest, for the three and nine months ended September 30, 2017 and 2016 . The interest expense capitalized was recorded as a cost of development and increased the carrying value of undeveloped land and construction in progress. Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands) Gross interest expense $ 28,331 $ 26,184 $ 84,577 $ 79,027 Capitalized interest and deferred financing costs (12,180 ) (11,208 ) (33,101 ) (37,838 ) Interest expense $ 16,151 $ 14,976 $ 51,476 $ 41,189

Noncontrolling Interests on the

Noncontrolling Interests on the Company's Consolidated Financial Statements	9 Months Ended
	Sep. 30, 2017
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 an approximate 97.9% , 97.5% and 97.2% common general partnership interest in the Operating Partnership as of September 30, 2017 , December 31, 2016 and September 30, 2016 , respectively. The remaining approximate 2.1% , 2.5% and 2.8% common limited partnership interest as of September 30, 2017 , December 31, 2016 and September 30, 2016 , respectively, was owned by non-affiliated investors and certain of our executive officers and directors in the form of noncontrolling common units. There were 2,077,193 , 2,381,543 and 2,631,276 common units outstanding held by these investors, executive officers and directors as of September 30, 2017 , December 31, 2016 and September 30, 2016 , 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 $145.6 million and $174.9 million as of September 30, 2017 and December 31, 2016 , 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.

Stockholders' Equity of the Com

Stockholders' Equity of the Company	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Stockholders' Equity of the Company	Stockholders’ Equity of the Company Preferred Stock Redemption On August 15, 2017 , the Company redeemed all 4,000,000 shares of its 6.375% Series H Cumulative Redeemable Preferred Stock (“Series H Preferred Stock”). The shares of Series H Preferred Stock were redeemed at a redemption price equal to their stated liquidation preference of $25.00 per share, representing $100.0 million in aggregate. The redemption payment did not include any additional accrued dividends because the redemption date was also the dividend payment date. On March 30, 2017 (the “Series G Redemption Date”), the Company redeemed all 4,000,000 shares of its 6.875% Series G Cumulative Redeemable Preferred Stock (“Series G Preferred Stock”). The shares of Series G Preferred Stock were redeemed at a redemption price equal to their stated liquidation preference of $25.00 per share, representing $100.0 million in aggregate, plus all accrued and unpaid dividends to the Series G Redemption Date. During the three and nine months ended September 30, 2017 , we recognized non-recurring non-cash charges of $3.7 million and $7.6 million , respectively, as a reduction to net income available to common stockholders for the original issuance costs related to the Series G and Series H Preferred Stock. Common Stock Issuance In January 2017, the Company completed an underwritten public offering of 4,427,500 shares of its common stock. The net offering proceeds, after deducting underwriting discounts and offering expenses, were approximately $308.8 million . We used a portion of the proceeds to partially fund our 2016 special dividend and used the remaining proceeds for general corporate uses, to fund development expenditures and to repay outstanding indebtedness. At-The-Market Stock Offering Program Under our current at-the-market stock offering program, which commenced in December 2014, we may offer and sell shares of our common stock having an aggregate gross sales price of up to $300.0 million from time to time in “at-the-market” offerings. No shares of common stock were sold under this program during the nine months ended September 30, 2017 . Since commencement of the program through September 30, 2017 , we have sold 2,459,165 shares of common stock having an aggregate gross sales price of $182.4 million . As of September 30, 2017 , shares of common stock having an aggregate gross sales price of up to $117.6 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. Payment of 2016 Special Cash Dividend On January 13, 2017 , the Company paid $184.3 million of special cash dividends, which was the equivalent of $1.90 of special cash dividend per share of common stock to stockholders of record on December 30, 2016 . This special dividend payment was in addition to the $36.4 million of regular dividends we also paid on January 13, 2017 to common stockholders, unitholders and RSU holders of record on December 30, 2016 .

Partners' Capital of the Operat

Partners' Capital of the Operating Partnership	9 Months Ended
	Sep. 30, 2017
Partners' Capital Notes [Abstract]
Partners’ Capital of the Operating Partnership	Partners’ Capital of the Operating Partnership Preferred Stock Redemption On August 15, 2017 , the Company redeemed all 4,000,000 shares of its 6.375% Series H Preferred Stock. For each share of Series H Preferred Stock that was outstanding, the Company had an equivalent number of 6.375% Series H Preferred Units (“Series H Preferred Units”) outstanding with substantially similar terms as the Series H Preferred Stock. In connection with the redemption of the Series H Preferred Stock, the Series H Preferred Units held by the Company were redeemed by the Operating Partnership. On March 30, 2017 , the Company redeemed all 4,000,000 shares of its 6.875% Series G Preferred Stock. For each share of Series G Preferred Stock that was outstanding, the Company had an equivalent number of 6.875% Series G Preferred Units (“Series G Preferred Units”) outstanding with substantially similar terms as the Series G Preferred Stock. In connection with the redemption of the Series G Preferred Stock, the Series G Preferred Units held by the Company were redeemed by the Operating Partnership. Issuance of Common Units In January 2017, the Company completed an underwritten public offering of 4,427,500 shares of its common stock as discussed in Note 7. The net offering proceeds of approximately $308.8 million were contributed by the Company to the Operating Partnership in exchange for 4,427,500 common units. 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-affiliated 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, 2017 December 31, 2016 September 30, 2016 Company owned common units in the Operating Partnership 98,382,256 93,219,439 92,272,492 Company owned general partnership interest 97.9 % 97.5 % 97.2 % Noncontrolling common units of the Operating Partnership 2,077,193 2,381,543 2,631,276 Ownership interest of noncontrolling interest 2.1 % 2.5 % 2.8 % For further discussion of the noncontrolling common units as of September 30, 2017 and December 31, 2016 , refer to Note 6.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation Stockholder Approved Equity Compensation Plans As of September 30, 2017 , we maintained one share-based incentive compensation plan, the Kilroy Realty 2006 Incentive Award Plan, as amended (the “2006 Plan”). As of September 30, 2017 , 2,004,127 shares were available for grant under the 2006 Plan. The calculation of shares available for grant is presented after taking into account a reserve for a sufficient number of shares to cover the vesting and payment of 2006 Plan awards that were outstanding on that date, including performance-based vesting awards at (i) levels actually achieved for the performance conditions (as defined below) for which the performance period has been completed and (ii) at target levels for the performance or market conditions (as defined below) for awards still in a performance period. 2017 Share-Based Compensation Grants In February 2017 , the Executive Compensation Committee of the Company’s Board of Directors awarded 229,976 restricted stock units (“RSUs”) to certain officers of the Company under the 2006 Plan, which included 130,956 RSUs (at the target level of performance), or 57% , that are subject to market and/or performance-based vesting requirements (the “2017 Performance-Based RSUs”) and 99,020 RSUs, or 43% , that are subject to time-based vesting requirements (the “2017 Time-Based RSUs”). 2017 Performance-Based RSU Grant The 2017 Performance-Based RSUs are scheduled to vest at the end of a three -year period based upon the achievement of pre-set FFO per share goals for the year ending December 31, 2017 (the “FFO performance condition”) and also based upon either the average FAD per share growth or the Company’s average debt to EBITDA ratio (the “other performance conditions”) or the average annual relative total stockholder return ranking for the Company compared to an established comparison group of companies (the “market condition”) for the three -year period ending December 31, 2019. The 2017 Performance-Based RSUs are also subject to a three -year service vesting provision and are scheduled to cliff vest at the end of the three -year period. The number of 2017 Performance-Based RSUs ultimately earned could fluctuate from the target number of 2017 Performance-Based RSUs granted based upon the levels of achievement for the FFO performance condition, the other performance conditions and the market condition. The estimate of the number of 2017 Performance-Based RSUs earned is evaluated quarterly during the performance period based on our estimate for each of the performance conditions measured against the applicable goals. As of September 30, 2017 , the number of 2017 Performance-Based RSUs estimated to be earned based on the Company’s estimate of the performance conditions measured against the applicable goals was 130,956 , and the compensation cost recorded to date for this program was based on that estimate. Compensation expense for the 2017 Performance-Based RSU grant will be recorded on a straight-line basis over the three -year period. Each 2017 Performance-Based RSU represents the right, subject to the applicable vesting conditions, to receive one share of our common stock in the future. The total fair value of the 2017 Performance-Based RSU grant was $10.3 million at February 24, 2017 . The determination of the fair value of the 2017 Performance-Based RSU grant with other performance conditions takes into consideration the likelihood of achievement of the FFO performance condition and the other performance conditions. The grant date fair value for the performance awards with a market condition was calculated using a Monte Carlo simulation pricing model based on the assumptions in the table below. For the portion of the 2017 Performance-Based RSUs subject to the market condition, for the nine months ended September 30, 2017 , we recorded compensation expense based upon the $80.89 fair value at February 24, 2017 . The following table summarizes the assumptions utilized in the Monte Carlo simulation pricing model: Fair Value Assumptions Fair value per share at February 24, 2017 $80.89 Expected share price volatility 21.00% Risk-free interest rate 1.39% Remaining expected life 2.8 years The computation of expected volatility is based on a blend of the historical volatility of our shares of common stock over approximately 5.6 years, as that is expected to be most consistent with future volatility and equates to a time period twice as long as the approximate 2.8 -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 February 24, 2017 . The expected life of the RSUs is equal to the remaining 2.8 year vesting period as of February 24, 2017 . 2017 Time-Based RSU Grant The 2017 Time-Based RSUs are scheduled to vest in three equal installments beginning on January 5, 2018 through January 5, 2020. Compensation expense for the 2017 Time-Based RSUs will be recognized on a straight-line basis over the three -year service vesting period. Each 2017 Time-Based RSU represents the right to receive one share of our common stock in the future. The total fair value of the 2017 Time-Based RSU grant was $7.5 million , which was based on the $73.30 and $77.16 closing share prices of the Company’s common stock on the NYSE on the February 3, 2017 and February 24, 2017 grant dates, respectively. Share-Based Award Activity During the nine months ended September 30, 2017 , 282,000 non-qualified stock options were exercised at an exercise price per share equal to $42.61 . As of September 30, 2017 , there were 29,500 stock options outstanding. Share-Based Compensation Cost Recorded During the Period The total compensation cost for all share-based compensation programs was $6.4 million and $6.8 million for the three months ended September 30, 2017 and 2016 , respectively, and $19.0 million and $19.3 million for the nine months ended September 30, 2017 and 2016 , respectively. Of the total share-based compensation costs, $1.7 million and $1.5 million was capitalized as part of real estate assets and deferred leasing costs for the three months ended September 30, 2017 and 2016 , respectively, and $5.4 million and $4.0 million for the nine months ended September 30, 2017 and 2016 , respectively. As of September 30, 2017 , there was approximately $30.9 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 1.9 years. The remaining compensation cost related to these nonvested incentive awards had been recognized in periods prior to September 30, 2017 .

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies General As of September 30, 2017 , we had commitments of approximately $755.0 million , excluding our ground lease commitments, for contracts and executed leases directly related to our operating properties and development projects. Environmental Matters We follow the policy of monitoring all of our properties, both acquisition and existing stabilized portfolio 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 our stabilized portfolio properties that would have a material adverse effect on our financial condition, results of operations and cash flow, or that we believe would require additional disclosure or the recording of a loss contingency. As of September 30, 2017 , we had accrued environmental remediation liabilities of approximately $27.1 million recorded on our consolidated balance sheets in connection with certain of our future development projects. It is possible that we could incur additional environmental remediation costs in connection with these future development projects. However, given we are in the pre-development phase on these future development projects, potential additional environmental costs are not reasonably estimable at this time and certain changes in estimates could occur as the site conditions, final project timing, design elements, actual soil conditions and other aspects of the projects, which may depend upon municipal and other approvals beyond the control of the Company, are determined.

Fair Value Measurements and Dis

Fair Value Measurements and Disclosures	9 Months Ended
	Sep. 30, 2017
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 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, 2017 and December 31, 2016 : Fair Value (Level 1) (1) September 30, 2017 December 31, 2016 Description (in thousands) Marketable securities (2) $ 18,851 $ 14,773 ________________________ (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 in the consolidated statements of operations. We also 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 on marketable securities recorded during the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Description (in thousands) (in thousands) Net gain on marketable securities $ 536 $ 481 $ 1,719 $ 867 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, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 Carrying Fair (1) Carrying Fair (1) (in thousands) Liabilities Secured debt, net $ 465,828 $ 467,968 $ 472,772 $ 469,234 Unsecured debt, net 1,909,381 1,983,737 1,847,351 1,900,487 Unsecured line of credit 60,000 60,087 — — ________________________ (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.

Net Income Available to Common

Net Income Available to Common Stockholders Per Share of the Company	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Net Income 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, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands, except share and per share amounts) Numerator: Net income attributable to Kilroy Realty Corporation $ 71,110 $ 53,895 $ 136,083 $ 261,050 Total preferred dividends (4,552 ) (3,313 ) (13,363 ) (9,938 ) Allocation to participating securities (1) (501 ) (426 ) (1,460 ) (1,244 ) Numerator for basic and diluted net income available to common stockholders $ 66,057 $ 50,156 $ 121,260 $ 249,868 Denominator: Basic weighted average vested shares outstanding 98,352,139 92,227,016 98,008,780 92,220,522 Effect of dilutive securities 559,473 693,390 582,268 611,016 Diluted weighted average vested shares and common share equivalents outstanding 98,911,612 92,920,406 98,591,048 92,831,538 Basic earnings per share: Net income available to common stockholders per share $ 0.67 $ 0.54 $ 1.24 $ 2.71 Diluted earnings per share: Net income available to common stockholders per share $ 0.67 $ 0.54 $ 1.23 $ 2.69 ________________________ (1) Participating securities include nonvested shares, certain time-based RSUs and vested market measure-based RSUs. Share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are considered participating securities. The impact of potentially dilutive common shares, including stock options, RSUs and other securities are considered in our diluted earnings per share calculation for the three and nine months ended September 30, 2017 and 2016 . Certain market measure-based RSUs are not included in dilutive securities for the three and nine months ended September 30, 2017 and 2016 , as not all performance metrics had been met by the end of the applicable reporting periods. See Note 9 “Share-Based Compensation” for additional information regarding share-based compensation.

Net Income Available to Commo26

Net Income Available to Common Unitholders Per Unit of the Operating Partnership	9 Months Ended
	Sep. 30, 2017
Earnings Per Unit [Abstract]
Net Income 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, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands, except unit and per unit amounts) Numerator: Net income attributable to Kilroy Realty, L.P. $ 72,402 $ 55,254 $ 138,427 $ 266,677 Total preferred distributions (4,552 ) (3,313 ) (13,363 ) (9,938 ) Allocation to participating securities (1) (501 ) (426 ) (1,460 ) (1,244 ) Numerator for basic and diluted net income available to common unitholders $ 67,349 $ 51,515 $ 123,604 $ 255,495 Denominator: Basic weighted average vested units outstanding 100,429,332 94,858,292 100,160,595 94,630,183 Effect of dilutive securities 559,473 693,390 582,268 611,016 Diluted weighted average vested units and common unit equivalents outstanding 100,988,805 95,551,682 100,742,863 95,241,199 Basic earnings per unit: Net income available to common unitholders per unit $ 0.67 $ 0.54 $ 1.23 $ 2.70 Diluted earnings per unit: Net income available to common unitholders per unit $ 0.67 $ 0.54 $ 1.23 $ 2.68 ________________________ (1) Participating securities include nonvested shares, certain time-based RSUs and vested market measure-based RSUs. Share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are considered participating securities. The impact of potentially dilutive common units, including stock options, RSUs and other securities are considered in our diluted earnings per share calculation for the three and nine months ended September 30, 2017 and 2016 . Certain market measure-based RSUs are not included in dilutive securities for the three and nine months ended September 30, 2017 and 2016 , as not all performance metrics had been met by the end of the applicable reporting periods. See Note 9 “Share-Based Compensation” for additional information regarding share-based compensation.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information of the Company	9 Months Ended
	Sep. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information of the Company	Supplemental Cash Flow Information of the Company Supplemental cash flow information is included as follows (in thousands): Nine Months Ended September 30, 2017 2016 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $31,880 and $36,468 as of September 30, 2017 and 2016, respectively $ 46,878 $ 42,858 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 104,409 $ 77,161 Tenant improvements funded directly by tenants $ 10,361 $ 16,803 Assumption of accrued liabilities in connection with acquisitions $ — $ 4,911 NON-CASH FINANCING TRANSACTIONS: Accrual of dividends and distributions payable to common stockholders and common unitholders $ 43,324 $ 36,109 Accrual of dividends and distributions payable to preferred stockholders and preferred unitholders $ — $ 1,656 Exchange of common units of the Operating Partnership into shares of the Company’s common stock $ 10,939 $ 39 Issuance of common units of the Operating Partnership in connection with an acquisition $ — $ 48,033 Secured debt assumed by buyers in connection with land dispositions $ — $ 2,322 The following is a reconciliation of our cash and cash equivalents and restricted cash at the beginning and end of the nine months ended September 30, 2017 and 2016 . Nine Months Ended September 30, 2017 2016 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 193,418 $ 56,508 Restricted cash at beginning of period 56,711 696 Cash and cash equivalents and restricted cash at beginning of period $ 250,129 $ 57,204 Cash and cash equivalents at end of period $ 64,954 $ 250,523 Restricted cash at end of period 179,276 57,501 Cash and cash equivalents and restricted cash at end of period $ 244,230 $ 308,024

Supplemental Cash Flow Inform28

Supplemental Cash Flow Information of the Operating Partnership	9 Months Ended
	Sep. 30, 2017
Other Significant Noncash Transactions [Line Items]
Supplemental Cash Flow Information of the Operating Partnership	Supplemental Cash Flow Information of the Company Supplemental cash flow information is included as follows (in thousands): Nine Months Ended September 30, 2017 2016 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $31,880 and $36,468 as of September 30, 2017 and 2016, respectively $ 46,878 $ 42,858 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 104,409 $ 77,161 Tenant improvements funded directly by tenants $ 10,361 $ 16,803 Assumption of accrued liabilities in connection with acquisitions $ — $ 4,911 NON-CASH FINANCING TRANSACTIONS: Accrual of dividends and distributions payable to common stockholders and common unitholders $ 43,324 $ 36,109 Accrual of dividends and distributions payable to preferred stockholders and preferred unitholders $ — $ 1,656 Exchange of common units of the Operating Partnership into shares of the Company’s common stock $ 10,939 $ 39 Issuance of common units of the Operating Partnership in connection with an acquisition $ — $ 48,033 Secured debt assumed by buyers in connection with land dispositions $ — $ 2,322 The following is a reconciliation of our cash and cash equivalents and restricted cash at the beginning and end of the nine months ended September 30, 2017 and 2016 . Nine Months Ended September 30, 2017 2016 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 193,418 $ 56,508 Restricted cash at beginning of period 56,711 696 Cash and cash equivalents and restricted cash at beginning of period $ 250,129 $ 57,204 Cash and cash equivalents at end of period $ 64,954 $ 250,523 Restricted cash at end of period 179,276 57,501 Cash and cash equivalents and restricted cash at end of period $ 244,230 $ 308,024
Kilroy Realty, L.P. [Member]
Other Significant Noncash Transactions [Line Items]
Supplemental Cash Flow Information of the Operating Partnership	Supplemental Cash Flow Information of the Operating Partnership: Supplemental cash flow information is included as follows (in thousands): Nine Months Ended September 30, 2017 2016 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $31,880 and $36,468 as of September 30, 2017 and 2016, respectively $ 46,878 $ 42,858 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 104,409 $ 77,161 Tenant improvements funded directly by tenants $ 10,361 $ 16,803 Assumption of accrued liabilities in connection with acquisitions $ — $ 4,911 NON-CASH FINANCING TRANSACTIONS: Accrual of distributions payable to common unitholders $ 43,324 $ 36,109 Accrual of distributions payable to preferred unitholders $ — $ 1,656 Issuance of common units of the Operating Partnership in connection with an acquisition $ — $ 48,033 Secured debt assumed by buyers in connection with land dispositions $ — $ 2,322 The following is a reconciliation of our cash and cash equivalents and restricted cash at the beginning and end of the nine months ended September 30, 2017 and 2016 . Nine Months Ended September 30, 2017 2016 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 193,418 $ 56,508 Restricted cash at beginning of period 56,711 696 Cash and cash equivalents and restricted cash at beginning of period $ 250,129 $ 57,204 Cash and cash equivalents at end of period $ 64,954 $ 250,523 Restricted cash at end of period 179,276 57,501 Cash and cash equivalents and restricted cash at end of period $ 244,230 $ 308,024

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On October 10, 2017, the Company completed the acquisition of a 1.2 acre development site located in the Little Italy neighborhood of downtown San Diego, California for $19.4 million in cash. On October 18, 2017 , aggregate dividends, distributions and dividend equivalents of $43.3 million were paid to common stockholders, common unitholders and RSU holders of record on September 30, 2017 .

Organization and Basis of Pre30

Organization and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2017
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, Kilroy Services, LLC (“KSLLC”), 100 First LLC, 303 Second LLC, Redwood 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, 100 First LLC, 303 Second LLC, Redwood 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, 2017 . 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 for the year ended December 31, 2016 .
New accounting pronouncements	Adoption of New Accounting Pronouncements Effective January 1, 2017, the Company adopted FASB ASU No. 2017-01 (“ASU 2017-01”) which clarifies the framework for determining whether an integrated set of assets and activities meets the definition of a business. The revised framework provides a screen for determining whether an integrated set of assets is a business combination or an asset acquisition and clarifies that when substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar assets, the set of assets and activities is deemed not to meet the definition of a business. As a result of our adoption of the guidance, which we adopted on a prospective basis, the Company expects that most of our future acquisitions of operating properties and development properties that were previously accounted for as business combinations will instead be accounted for as asset acquisitions under the new guidance. In addition, we expect that most of the transaction costs associated with these future acquisitions will be capitalized as part of the purchase price of the acquisition instead of being expensed as incurred to acquisition-related expenses. The Company did not have any acquisitions of operating properties during the nine months ended September 30, 2017 . Also effective January 1, 2017, the Company adopted ASU No. 2016-18 (“ASU 2016-18”) which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. The Company adopted ASU 2016-18 on a retrospective basis. Therefore, amounts generally described as restricted cash and restricted cash equivalents are included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the Company’s consolidated statements of cash flows for the nine months ended September 30, 2017 and 2016 . As a result of the adoption of ASU 2016-18, the change in restricted cash is no longer presented as a separate line item within cash flows from investing activities on the Company’s consolidated statements of cash flows since such balances are now included in total cash at both the beginning and end of the reporting period. As a result, for the nine months ended September 30, 2016 , the Company had net cash used in investing activities of $67.4 million instead of net cash used in investing activities of $124.2 million as previously reported since the Company had an increase in restricted cash of $56.8 million during the nine months ended September 30, 2016 primarily due to $48.4 million of restricted cash that was held at qualified intermediaries to facilitate potential future Section1031 Exchanges. In addition, effective January 1, 2017, the Company adopted ASU No. 2016-09 (“ASU 2016-09”) which simplified several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The adoption of this guidance did not have an impact on our consolidated financial statements or notes to our consolidated financial statements. Recently Issued Accounting Pronouncements ASU No. 2016-02 “Leases (Topic 842)” On February 25, 2016, the FASB issued ASU No. 2016-02 (“ASU 2016-02”) to amend the accounting guidance for leases. The accounting applied by a lessor is largely unchanged under ASU 2016-02. However, the standard requires lessees to recognize lease assets and lease liabilities for leases classified as operating leases on the balance sheet. Lessees will recognize in the statement of financial position a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. If a lessee makes this election, it will recognize lease expense for such leases generally on a straight-line basis over the lease term. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 and early adoption is permitted. We are currently conducting our evaluation of the impact of the guidance on our consolidated financial statements and have an active project team working on the evaluation and implementation of the guidance. We currently believe that the adoption of the standard will not significantly change the accounting for operating leases on our consolidated balance sheets where we are the lessor, and that such leases will be accounted for in a similar method to existing standards with the underlying leased asset being reported and recognized as a real estate asset. We currently expect that certain non-lease components will need to be accounted for separately from the lease components, with the lease components continuing to be recognized on a straight-line basis over the term of the lease and certain non-lease components (such as common area maintenance) being accounted for under the new revenue recognition guidance in ASU 2014-09 discussed below, even when revenue for such non-lease components is not separately stipulated in the lease. In addition, under ASU 2016-02, lessors will only be permitted to capitalize and amortize incremental direct leasing costs. As a result, we expect that upon the adoption of the standard, we will no longer be able to capitalize and amortize certain leasing related costs and instead will expense these costs as incurred. We currently expect this could have a material impact to the Company’s results of operations upon adoption of the standard. For leases where we are the lessee, specifically for our ground leases, we currently believe that the adoption of the standard will significantly change the accounting on our consolidated balance sheets since both existing ground leases and any future ground leases will be required to be recorded on the Company’s consolidated balance sheets as an obligation of the Company. We currently believe that existing ground leases executed before the January 1, 2019 adoption date will continue to be accounted for as operating leases and will not have a material impact on our recognition of ground lease expense or our results of operations. However, we believe that we will be required to recognize a right of use asset and a lease liability on our consolidated balance sheets equal to the present value of the minimum lease payments required in accordance with each ground lease. As of September 30, 2017 , our future undiscounted minimum rental payments under these leases totaled $252.8 million , with several of the leases containing provisions for rental payments to fluctuate based on fair market value and operating income measurements with expirations through 2093. In addition, we currently believe that for new ground leases entered into after the adoption date of the new standard, such leases could be required to be accounted for as a financing type lease, resulting in ground lease expense recorded using the effective interest method instead of on a straight-line basis over the term of the lease. This could have a significant impact on our results of operations if we enter into material new ground leases after the date of adoption since ground lease expense calculated using the effective interest method results in an increased amount of ground lease expense in the earlier years of a ground lease as compared to the current straight-line method. We will adopt the guidance on a modified retrospective basis as required by ASU 2016-02. We are in the process of evaluating whether we will elect to apply the practical expedients identified in the standard but currently believe that we may do so. ASU No. 2014-09 “ Revenue From Contracts with Customers (Topic 606)” In May 2014, the FASB issued ASU 2014-09 “Revenue From Contracts with Customers (Topic 606)” (“ASU 2014-09”). The objective of ASU 2014-09 is to establish a single comprehensive model for entities to use in accounting for revenue from contracts with customers and will supersede most of the existing revenue recognition guidance. On May 9, 2016 and December 21, 2016, the FASB issued ASU No. 2016-12 and ASU No. 2016-20, which provides practical expedients, technical corrections, and improvements for certain aspects of ASU No. 2014-09. Public business entities may elect to adopt the amendments as of the original effective date; however, adoption is required for annual reporting periods beginning after December 15, 2017. We have compiled an inventory of the sources of revenue that will be impacted by ASU 2014-09. Specifically, we have evaluated the impact of the guidance on timing of gain recognition for dispositions and currently do not believe there will be a material impact to our consolidated financial statements given the simplicity of the Company’s historical disposition transactions. In addition, we currently believe that certain non-lease components of revenue from leases such as common area maintenance and certain types of parking revenue may be impacted by ASU 2014-09 when we adopt ASU 2016-02 on January 1, 2019. We are in the process of evaluating the impact on these non-lease revenue components and currently believe the impact will be limited to the income statement presentation of revenue and not the total amount of revenue recognized. Other Recently Issued Pronouncements On May 10, 2017, the FASB issued ASU No. 2017-09 “Compensation - Stock Compensation (Topic 718)” to clarify the scope of modification accounting. Under the guidance, an entity will not apply modification accounting to a share-based payment award if the award’s fair value, vesting conditions, and classification as an equity or liability instrument remain the same immediately before and after the change. The guidance is effective for annual periods beginning after December 15, 2017 and early adoption is permitted. The Company does not currently anticipate that the guidance will have a material impact on our consolidated financial statements or notes to our consolidated financial statements. On February 22, 2017, the FASB issued ASU No. 2017-05 “Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20)” (“ASU 2017-05”) to provide guidance and clarify the scope of the original guidance within Subtopic 610-20 “Gains and Losses from the Derecognition of Nonfinancial Assets” that was issued in connection with ASU 2014-09, which provided guidance for recognizing gains and losses from the transfer of nonfinancial assets in transactions with noncustomers. ASU 2017-05 additionally adds guidance pertaining to the partial sales of real estate and clarifies that nonfinancial assets within the scope of Accounting Standards Codification Subtopic 610-20 may include nonfinancial assets transferred within a legal entity to a counterparty. For example, a parent may transfer control of nonfinancial assets by transferring ownership interests in a consolidated subsidiary. ASU 2017-05 is effective for fiscal years beginning after December 15, 2017, with early application permitted for fiscal years beginning after December 15, 2016. We are currently evaluating the impact of ASU 2017-05 on our consolidated financial statements and currently do not anticipate that the guidance will have a material impact on our consolidated financial statements or notes to our consolidated financial statements. On August 26, 2016, the FASB issued ASU No. 2016-15 (“ASU 2016-15”) to provide guidance for areas where there is diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. ASU 2016-15 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company does not currently anticipate that the guidance will have a material impact on our consolidated financial statements or notes to our consolidated financial statements. On June 16, 2016, the FASB issued ASU No. 2016-13 (“ASU 2016-13”) to amend the accounting for credit losses for certain financial instruments. Under the new guidance, an entity recognizes its estimate of expected credit losses as an allowance, which the FASB believes will result in more timely recognition of such losses. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company does not currently anticipate that the guidance will have a material impact on our consolidated financial statements or notes to our consolidated financial statements. On January 5, 2016, the FASB issued ASU No. 2016-01 (“ASU 2016-01”) to amend the accounting guidance on the classification and measurement of financial instruments. The standard requires that all investments in equity securities, including other ownership interests, are carried at fair value through net income. This requirement does not apply to investments that qualify for equity method accounting or to those that result in consolidation of the investee or for which the entity has elected the predictability exception to fair value measurement. Additionally, the standard requires that the portion of the total fair value change caused by a change in instrument-specific credit risk for financial liabilities for which the fair value option has been elected would be recognized in other comprehensive income. Any accumulated amount remaining in other comprehensive income is reclassified to earnings when the liability is extinguished. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017. The Company does not currently anticipate that the guidance will have a material impact on our consolidated financial statements or notes to our consolidated financial statements.

Organization and Basis of Pre31

Organization and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of real estate properties	As of September 30, 2017 , the following properties were excluded from our stabilized portfolio. We did not have any redevelopment properties at September 30, 2017 . Number of Properties/Projects Estimated Rentable Square Feet (1) Development projects under construction (2) 4 1,800,000 ________________________ (1) Estimated rentable square feet upon completion. (2) Development projects under construction also include 96,000 square feet of retail space and 237 residential units in addition to the estimated office rentable square feet noted above. Our stabilized portfolio of operating properties was comprised of the following properties at September 30, 2017 : Number of Buildings Rentable Square Feet (unaudited) Number of Tenants Percentage Occupied (unaudited) Percentage Leased (unaudited) Stabilized Office Properties 101 13,720,598 515 94.0 % 96.2 % Number of Number of Units Percentage Occupied (unaudited) Percentage Leased (unaudited) Stabilized Residential Property 1 200 72.0 % 74.5 %

Dispositions (Tables)

Dispositions (Tables)	9 Months Ended
	Sep. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Schedule of dispositions and real estate assets held for sale	The following table summarizes the properties sold during the nine months ended September 30, 2017 . Location Property Type Month of Disposition Number of Buildings Rentable Square Feet Sales Price (1) (in millions) 5717 Pacific Center Boulevard, San Diego, CA (2) Office January 1 67,995 $ 12.1 Sorrento Mesa and Mission Valley Properties (3) Office September 10 675,143 174.5 Total Dispositions 11 743,138 $ 186.6 ________________________ (1) Represents gross sales price before the impact of broker commissions and closing costs. (2) This property was classified as held for sale at December 31, 2016 . (3) The Sorrento Mesa and Mission Valley Properties includes the following properties: 10390, 10394, 10398, 10421, 10445 and 10455 Pacific Center Court, 2355, 2365, 2375 and 2385 Northside Drive and Pacific Corporate Center - Lot 8, a 5.0 acre undeveloped land parcel.

Receivables (Tables)

Receivables (Tables)	9 Months Ended
	Sep. 30, 2017
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, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 (in thousands) Current receivables $ 20,746 $ 15,172 Allowance for uncollectible tenant receivables (2,120 ) (1,712 ) Current receivables, net $ 18,626 $ 13,460
Deferred Rent Receivables, net	Deferred rent receivables, net consisted of the following as of September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 (in thousands) Deferred rent receivables $ 241,929 $ 220,501 Allowance for deferred rent receivables (2,970 ) (1,524 ) Deferred rent receivables, net $ 238,959 $ 218,977

Prepaid Expenses and Other As34

Prepaid Expenses and Other Assets, Net (Tables)	9 Months Ended
	Sep. 30, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses and other assets, net	Prepaid expenses and other assets, net consisted of the following at September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 (in thousands) Furniture, fixtures and other long-lived assets, net $ 39,889 $ 40,395 Notes receivable (1) 19,838 19,439 Prepaid expenses & acquisition deposits 48,988 10,774 Total prepaid expenses and other assets, net $ 108,715 $ 70,608 _______________ (1) Approximately $15.1 million of our notes receivable are secured by real estate.

Secured and Unsecured Debt of35

Secured and Unsecured Debt of the Operating Partnership (Tables) - Kilroy Realty, L.P. [Member]	9 Months Ended
	Sep. 30, 2017
Debt Instrument [Line Items]
Unsecured revolving credit facility	The following table summarizes the balance and terms of our unsecured term loan facility as of September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 (in thousands) Outstanding borrowings (1) $ — $ 150,000 Remaining borrowing capacity 150,000 — Total borrowing capacity (2) $ 150,000 $ 150,000 Interest rate (3) 2.33 % 1.85 % Undrawn facility fee-annual rate (4) 0.200 % — % Maturity date July 2022 July 2019 ________________________ (1) In July 2017, the unsecured term loan facility was paid down and the Facility was amended to include two, six-month delayed draw options on the unsecured term loan facility. The Company may draw on the unsecured term loan facility through July 2018, at which time the outstanding balance will become the balance of the unsecured term loan facility and no additional draws may be made. However, if the Company does not draw at least $75.0 million by the end of first option term in January 2018, the total borrowing capacity under the Facility will be reduced by 50% of the unutilized borrowing capacity at that time. The Company intends to draw $75.0 million prior to the end of the first option term in January 2018. (2) As of September 30, 2017 and December 31, 2016 , $1.2 million and $0.7 million of unamortized deferred financing costs, respectively, remained to be amortized through the maturity date of our unsecured term loan facility. (3) Our unsecured term loan facility interest rate was calculated based on an annual rate of LIBOR plus 1.100% and LIBOR plus 1.150% as of September 30, 2017 and December 31, 2016 , respectively. The following table summarizes the balance and terms of our unsecured revolving credit facility as of September 30, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 (in thousands) Outstanding borrowings $ 60,000 $ — Remaining borrowing capacity 690,000 600,000 Total borrowing capacity (1) $ 750,000 $ 600,000 Interest rate (2) 2.24 % 1.82 % Facility fee-annual rate (3) 0.200% Maturity date July 2022 July 2019 ________________________ (1) We may elect to borrow, subject to bank approval and obtaining commitments for any additional borrowing capacity, up to an additional $600.0 million under an accordion feature under the terms of the unsecured revolving credit facility and unsecured term loan facility. (2) Our unsecured revolving credit facility interest rate was calculated based on an annual rate of LIBOR plus 1.000% and LIBOR plus 1.050% as of September 30, 2017 and December 31, 2016 , respectively. (3) Our facility fee is paid on a quarterly basis and is calculated based on the total borrowing capacity. In addition to the facility fee, we incurred debt origination and legal costs. As of September 30, 2017 and December 31, 2016 , $6.3 million and $3.3 million of unamortized deferred financing costs, respectively, remained to be amortized through the maturity date of our unsecured revolving credit facility, which are included in prepaid expenses and other assets, net on our consolidated balance sheets.
Schedule of debt maturities	The following table summarizes the stated debt maturities and scheduled amortization payments of our issued and outstanding debt, excluding unamortized debt discounts, premiums and deferred financing costs, as of September 30, 2017 : Year (in thousands) Remaining 2017 $ 1,545 2018 451,669 2019 76,309 2020 255,137 2021 5,342 Thereafter 1,659,023 Total (1) $ 2,449,025 ________________________ (1) Includes gross principal balance of outstanding debt before the effect of the following at September 30, 2017 : $10.9 million of unamortized deferred financing costs, $6.0 million of unamortized discounts for the unsecured senior notes and $3.0 million of unamortized premiums for the secured debt.
Capitalized interest and loan fees	The following table sets forth gross interest expense, including debt discount/premium and deferred financing cost amortization, net of capitalized interest, for the three and nine months ended September 30, 2017 and 2016 . The interest expense capitalized was recorded as a cost of development and increased the carrying value of undeveloped land and construction in progress. Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands) Gross interest expense $ 28,331 $ 26,184 $ 84,577 $ 79,027 Capitalized interest and deferred financing costs (12,180 ) (11,208 ) (33,101 ) (37,838 ) Interest expense $ 16,151 $ 14,976 $ 51,476 $ 41,189

Partners' Capital of the Oper36

Partners' Capital of the Operating Partnership (Tables)	9 Months Ended
	Sep. 30, 2017
Partners' Capital Notes [Abstract]
Schedule of 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-affiliated 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, 2017 December 31, 2016 September 30, 2016 Company owned common units in the Operating Partnership 98,382,256 93,219,439 92,272,492 Company owned general partnership interest 97.9 % 97.5 % 97.2 % Noncontrolling common units of the Operating Partnership 2,077,193 2,381,543 2,631,276 Ownership interest of noncontrolling interest 2.1 % 2.5 % 2.8 %

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2017
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 February 24, 2017 $80.89 Expected share price volatility 21.00% Risk-free interest rate 1.39% Remaining expected life 2.8 years

Fair Value Measurements and D38

Fair Value Measurements and Disclosures (Tables)	9 Months Ended
	Sep. 30, 2017
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, 2017 and December 31, 2016 : Fair Value (Level 1) (1) September 30, 2017 December 31, 2016 Description (in thousands) Marketable securities (2) $ 18,851 $ 14,773 ________________________ (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 on marketable securities recorded during the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Description (in thousands) (in thousands) Net gain on marketable securities $ 536 $ 481 $ 1,719 $ 867
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, 2017 and December 31, 2016 : September 30, 2017 December 31, 2016 Carrying Fair (1) Carrying Fair (1) (in thousands) Liabilities Secured debt, net $ 465,828 $ 467,968 $ 472,772 $ 469,234 Unsecured debt, net 1,909,381 1,983,737 1,847,351 1,900,487 Unsecured line of credit 60,000 60,087 — — ________________________ (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.

Net Income Available to Commo39

Net Income Available to Common Stockholders Per Share of the Company (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income 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, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands, except share and per share amounts) Numerator: Net income attributable to Kilroy Realty Corporation $ 71,110 $ 53,895 $ 136,083 $ 261,050 Total preferred dividends (4,552 ) (3,313 ) (13,363 ) (9,938 ) Allocation to participating securities (1) (501 ) (426 ) (1,460 ) (1,244 ) Numerator for basic and diluted net income available to common stockholders $ 66,057 $ 50,156 $ 121,260 $ 249,868 Denominator: Basic weighted average vested shares outstanding 98,352,139 92,227,016 98,008,780 92,220,522 Effect of dilutive securities 559,473 693,390 582,268 611,016 Diluted weighted average vested shares and common share equivalents outstanding 98,911,612 92,920,406 98,591,048 92,831,538 Basic earnings per share: Net income available to common stockholders per share $ 0.67 $ 0.54 $ 1.24 $ 2.71 Diluted earnings per share: Net income available to common stockholders per share $ 0.67 $ 0.54 $ 1.23 $ 2.69 ________________________ (1) Participating securities include nonvested shares, certain time-based RSUs and vested market measure-based RSUs.

Net Income Available to Commo40

Net Income Available to Common Unitholders Per Unit of the Operating Partnership (Tables)	9 Months Ended
	Sep. 30, 2017
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, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands, except share and per share amounts) Numerator: Net income attributable to Kilroy Realty Corporation $ 71,110 $ 53,895 $ 136,083 $ 261,050 Total preferred dividends (4,552 ) (3,313 ) (13,363 ) (9,938 ) Allocation to participating securities (1) (501 ) (426 ) (1,460 ) (1,244 ) Numerator for basic and diluted net income available to common stockholders $ 66,057 $ 50,156 $ 121,260 $ 249,868 Denominator: Basic weighted average vested shares outstanding 98,352,139 92,227,016 98,008,780 92,220,522 Effect of dilutive securities 559,473 693,390 582,268 611,016 Diluted weighted average vested shares and common share equivalents outstanding 98,911,612 92,920,406 98,591,048 92,831,538 Basic earnings per share: Net income available to common stockholders per share $ 0.67 $ 0.54 $ 1.24 $ 2.71 Diluted earnings per share: Net income available to common stockholders per share $ 0.67 $ 0.54 $ 1.23 $ 2.69 ________________________ (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, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands, except unit and per unit amounts) Numerator: Net income attributable to Kilroy Realty, L.P. $ 72,402 $ 55,254 $ 138,427 $ 266,677 Total preferred distributions (4,552 ) (3,313 ) (13,363 ) (9,938 ) Allocation to participating securities (1) (501 ) (426 ) (1,460 ) (1,244 ) Numerator for basic and diluted net income available to common unitholders $ 67,349 $ 51,515 $ 123,604 $ 255,495 Denominator: Basic weighted average vested units outstanding 100,429,332 94,858,292 100,160,595 94,630,183 Effect of dilutive securities 559,473 693,390 582,268 611,016 Diluted weighted average vested units and common unit equivalents outstanding 100,988,805 95,551,682 100,742,863 95,241,199 Basic earnings per unit: Net income available to common unitholders per unit $ 0.67 $ 0.54 $ 1.23 $ 2.70 Diluted earnings per unit: Net income available to common unitholders per unit $ 0.67 $ 0.54 $ 1.23 $ 2.68 ________________________ (1) Participating securities include nonvested shares, certain time-based RSUs and vested market measure-based RSUs.

Supplemental Cash Flow Inform41

Supplemental Cash Flow Information of the Company (Tables)	9 Months Ended
	Sep. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Schedule of supplemental cash flows	Supplemental cash flow information is included as follows (in thousands): Nine Months Ended September 30, 2017 2016 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $31,880 and $36,468 as of September 30, 2017 and 2016, respectively $ 46,878 $ 42,858 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 104,409 $ 77,161 Tenant improvements funded directly by tenants $ 10,361 $ 16,803 Assumption of accrued liabilities in connection with acquisitions $ — $ 4,911 NON-CASH FINANCING TRANSACTIONS: Accrual of dividends and distributions payable to common stockholders and common unitholders $ 43,324 $ 36,109 Accrual of dividends and distributions payable to preferred stockholders and preferred unitholders $ — $ 1,656 Exchange of common units of the Operating Partnership into shares of the Company’s common stock $ 10,939 $ 39 Issuance of common units of the Operating Partnership in connection with an acquisition $ — $ 48,033 Secured debt assumed by buyers in connection with land dispositions $ — $ 2,322
Reconciliation of cash and cash equivalents and restricted cash	The following is a reconciliation of our cash and cash equivalents and restricted cash at the beginning and end of the nine months ended September 30, 2017 and 2016 . Nine Months Ended September 30, 2017 2016 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 193,418 $ 56,508 Restricted cash at beginning of period 56,711 696 Cash and cash equivalents and restricted cash at beginning of period $ 250,129 $ 57,204 Cash and cash equivalents at end of period $ 64,954 $ 250,523 Restricted cash at end of period 179,276 57,501 Cash and cash equivalents and restricted cash at end of period $ 244,230 $ 308,024
Reconciliation of cash and cash equivalents and restricted cash	The following is a reconciliation of our cash and cash equivalents and restricted cash at the beginning and end of the nine months ended September 30, 2017 and 2016 . Nine Months Ended September 30, 2017 2016 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 193,418 $ 56,508 Restricted cash at beginning of period 56,711 696 Cash and cash equivalents and restricted cash at beginning of period $ 250,129 $ 57,204 Cash and cash equivalents at end of period $ 64,954 $ 250,523 Restricted cash at end of period 179,276 57,501 Cash and cash equivalents and restricted cash at end of period $ 244,230 $ 308,024

Supplemental Cash Flow Inform42

Supplemental Cash Flow Information of the Operating Partnership (Tables)	9 Months Ended
	Sep. 30, 2017
Other Significant Noncash Transactions [Line Items]
Schedule of supplemental cash flows	Supplemental cash flow information is included as follows (in thousands): Nine Months Ended September 30, 2017 2016 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $31,880 and $36,468 as of September 30, 2017 and 2016, respectively $ 46,878 $ 42,858 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 104,409 $ 77,161 Tenant improvements funded directly by tenants $ 10,361 $ 16,803 Assumption of accrued liabilities in connection with acquisitions $ — $ 4,911 NON-CASH FINANCING TRANSACTIONS: Accrual of dividends and distributions payable to common stockholders and common unitholders $ 43,324 $ 36,109 Accrual of dividends and distributions payable to preferred stockholders and preferred unitholders $ — $ 1,656 Exchange of common units of the Operating Partnership into shares of the Company’s common stock $ 10,939 $ 39 Issuance of common units of the Operating Partnership in connection with an acquisition $ — $ 48,033 Secured debt assumed by buyers in connection with land dispositions $ — $ 2,322
Reconciliation of cash and cash equivalents and restricted cash	The following is a reconciliation of our cash and cash equivalents and restricted cash at the beginning and end of the nine months ended September 30, 2017 and 2016 . Nine Months Ended September 30, 2017 2016 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 193,418 $ 56,508 Restricted cash at beginning of period 56,711 696 Cash and cash equivalents and restricted cash at beginning of period $ 250,129 $ 57,204 Cash and cash equivalents at end of period $ 64,954 $ 250,523 Restricted cash at end of period 179,276 57,501 Cash and cash equivalents and restricted cash at end of period $ 244,230 $ 308,024
Reconciliation of cash and cash equivalents and restricted cash	The following is a reconciliation of our cash and cash equivalents and restricted cash at the beginning and end of the nine months ended September 30, 2017 and 2016 . Nine Months Ended September 30, 2017 2016 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 193,418 $ 56,508 Restricted cash at beginning of period 56,711 696 Cash and cash equivalents and restricted cash at beginning of period $ 250,129 $ 57,204 Cash and cash equivalents at end of period $ 64,954 $ 250,523 Restricted cash at end of period 179,276 57,501 Cash and cash equivalents and restricted cash at end of period $ 244,230 $ 308,024
Kilroy Realty, L.P. [Member]
Other Significant Noncash Transactions [Line Items]
Schedule of supplemental cash flows	Supplemental cash flow information is included as follows (in thousands): Nine Months Ended September 30, 2017 2016 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $31,880 and $36,468 as of September 30, 2017 and 2016, respectively $ 46,878 $ 42,858 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 104,409 $ 77,161 Tenant improvements funded directly by tenants $ 10,361 $ 16,803 Assumption of accrued liabilities in connection with acquisitions $ — $ 4,911 NON-CASH FINANCING TRANSACTIONS: Accrual of distributions payable to common unitholders $ 43,324 $ 36,109 Accrual of distributions payable to preferred unitholders $ — $ 1,656 Issuance of common units of the Operating Partnership in connection with an acquisition $ — $ 48,033 Secured debt assumed by buyers in connection with land dispositions $ — $ 2,322
Reconciliation of cash and cash equivalents and restricted cash	The following is a reconciliation of our cash and cash equivalents and restricted cash at the beginning and end of the nine months ended September 30, 2017 and 2016 . Nine Months Ended September 30, 2017 2016 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 193,418 $ 56,508 Restricted cash at beginning of period 56,711 696 Cash and cash equivalents and restricted cash at beginning of period $ 250,129 $ 57,204 Cash and cash equivalents at end of period $ 64,954 $ 250,523 Restricted cash at end of period 179,276 57,501 Cash and cash equivalents and restricted cash at end of period $ 244,230 $ 308,024
Reconciliation of cash and cash equivalents and restricted cash	The following is a reconciliation of our cash and cash equivalents and restricted cash at the beginning and end of the nine months ended September 30, 2017 and 2016 . Nine Months Ended September 30, 2017 2016 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 193,418 $ 56,508 Restricted cash at beginning of period 56,711 696 Cash and cash equivalents and restricted cash at beginning of period $ 250,129 $ 57,204 Cash and cash equivalents at end of period $ 64,954 $ 250,523 Restricted cash at end of period 179,276 57,501 Cash and cash equivalents and restricted cash at end of period $ 244,230 $ 308,024

Organization and Basis of Pre43

Organization and Basis of Presentation (Details) - Sep. 30, 2017	Total	ft²	tenant	number_of_residential_units	building	project	property_units	property
Stabilized office properties [Member]
Real Estate Properties [Line Items]
Number of Buildings					101			4
Rentable Square Feet (unaudited)		13,720,598
Number of Tenants | tenant			515
Percentage Occupied (unaudited)	94.00%
Percentage Leased (unaudited)	96.20%
Stabilized residential properties [Member]
Real Estate Properties [Line Items]
Number of Buildings | building					1
Percentage Occupied (unaudited)	72.00%
Percentage Leased (unaudited)	74.50%
Number of Units | property_units							200
Development projects under construction [Member]
Real Estate Properties [Line Items]
Number of Buildings | project						4
Rentable Square Feet (unaudited)		1,800,000
Number of residential units | number_of_residential_units				237
Retail site [Member] | Development projects under construction [Member]
Real Estate Properties [Line Items]
Rentable Square Feet (unaudited)		96,000

Organization and Basis of Pre44

Organization and Basis of Presentation (Details Textual) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2017property_partnership	Sep. 30, 2017ft²	Sep. 30, 2017building	Sep. 30, 2017project	Sep. 30, 2017VIE	Sep. 30, 2017a	Sep. 30, 2017property	Dec. 31, 2016USD ($)VIE
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Lease-up properties occupancy percentage	95.00%
Common general partnership interest in the Operating Partnership	97.90%	97.20%									97.50%
Common limited partnership interest in the Operating Partnership	2.10%	2.80%									2.50%
Number of VIEs | VIE								2			3
VIE assets			$ 429,400								$ 654,300
VIE liabilities			151,400								166,100
Noncontrolling interest in VIE			128,106								130,732
Net cash (used in) provided by investing activities	$ (180,712)	$ (67,402)
Increase in restricted cash	$ 56,800
Restricted cash		48,400
Ground leases, future minimum payments receivable			252,800
101 First LLC and 303 Second LLC [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Common general partnership interest in the Operating Partnership	56.00%
Noncontrolling interest in VIE			121,800								124,300
Kilroy Realty Finance, Inc. [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Common general partnership interest in the Finance Partnership (percentage)	1.00%
Kilroy Realty, L.P. [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Percentage of limited partnership interest owned by Operating Partnership	99.00%
Net cash (used in) provided by investing activities	$ (180,712)	$ (67,402)
Redwood LLC [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Common general partnership interest in the Operating Partnership	93.00%
Office properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Rentable Square Feet (unaudited) | ft²					13,720,598
Number of Buildings						101				4
Area of land | a									47
Office properties [Member] | Washington [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of Buildings | property										12
Development properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Rentable Square Feet (unaudited) | ft²					1,800,000
Number of Buildings | project							4
Number of property partnerships | property_partnership				3
Development properties [Member] | San Francisco, California [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Rentable Square Feet (unaudited) | ft²					365,359
Development sites [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of Buildings | project							5
Properties and development projects [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Property ownership percentage	100.00%
Real estate investment [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
VIE assets			$ 383,700								$ 588,600
Scenario, Previously Reported [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Net cash (used in) provided by investing activities	$ 124,200

Dispositions (Details)

Dispositions (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)ft²aproperty	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)ft²aproperty	Sep. 30, 2016USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gains on sales of depreciable operating properties	$ 37,250	$ 18,312	$ 39,507	$ 164,302
5717 Pacific Center Boulevard, San Diego, CA [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings | property	1		1
Rentable Square Feet | ft²	67,995		67,995
Sales Price (1) (in millions)			$ 12,100
Sorrento Mesa and Mission Valley Properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings | property	10		10
Rentable Square Feet | ft²	675,143		675,143
Sales Price (1) (in millions)			$ 174,500
5717 Pacific Center Boulevard, San Diego, CA, and Sorrento Mesa and Mission Valley Portfolio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings | property	11		11
Rentable Square Feet | ft²	743,138		743,138
Sales Price (1) (in millions)			$ 186,600
5717 Pacific Center Boulevard, San Diego, CA, and Sorrento Mesa and Mission Valley Portfolio [Member] | Restricted Cash [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gains on sales of depreciable operating properties			170,600
5717 Pacific Center Boulevard, San Diego, CA, and Sorrento Mesa and Mission Valley Portfolio [Member] | Operating Properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gains on sales of depreciable operating properties			39,500
5717 Pacific Center Boulevard, San Diego, CA, and Sorrento Mesa and Mission Valley Portfolio [Member] | Land [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gains on sales of depreciable operating properties			$ 400
5975 Pacific Mesa Court [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of land | a	5		5

Receivables (Details)

Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current Receivables, net
Current receivables	$ 20,746	$ 15,172
Allowance for uncollectible tenant receivables	(2,120)	(1,712)
Current receivables, net	18,626	13,460
Deferred Rent Receivables, net
Deferred rent receivables	241,929	220,501
Allowance for deferred rent receivables	(2,970)	(1,524)
Deferred rent receivables, net	$ 238,959	$ 218,977

Prepaid Expenses and Other As47

Prepaid Expenses and Other Assets, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Furniture, fixtures and other long-lived assets, net	$ 39,889	$ 40,395
Notes receivable (1)	19,838	19,439
Prepaid expenses & acquisition deposits	48,988	10,774
Total prepaid expenses and other assets, net	108,715	$ 70,608
Secured debt [Member]
Debt Instrument [Line Items]
Notes receivable (1)	$ 15,100

Secured and Unsecured Debt of48

Secured and Unsecured Debt of the Operating Partnership - Unsecured Senior Notes - Private Placement (Details) - Kilroy Realty, L.P. [Member] - USD ($)	9 Months Ended
	Sep. 30, 2017	Feb. 17, 2017
Debt Instrument [Line Items]
Long-term debt, gross	$ 2,449,025,000
Unsecured Debt [Member] | Three point three five percent Series A Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Long-term debt, gross	175,000,000	$ 175,000,000
Stated coupon rate		3.35%
Unsecured Debt [Member] | Three point four five percent Series B Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 75,000,000	$ 75,000,000
Stated coupon rate		3.45%
Unsecured Debt [Member] | Series A and B Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Operating partnership, payment percent	5.00%
Operating partnership, total payment percentage	100.00%

Secured and Unsecured Debt of49

Secured and Unsecured Debt of the Operating Partnership - Unsecured Revolving Credit Facility and Term Loan Facility (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Unsecured debt, net (Notes 5 and 11)	$ 1,909,381,000	$ 1,847,351,000
Terms of the Credit Facility
Outstanding borrowings	60,000,000	0
Total borrowing capacity (1)		150,000,000
Kilroy Realty, L.P. [Member]
Debt Instrument [Line Items]
Unsecured debt, net (Notes 5 and 11)	1,909,381,000	1,847,351,000
Terms of the Credit Facility
Outstanding borrowings	60,000,000	0
Unamortized deferred financing costs	10,900,000
Kilroy Realty, L.P. [Member] | Revolving Credit Facility [Member]
Terms of the Credit Facility
Outstanding borrowings	60,000,000	0
Remaining borrowing capacity	690,000,000	600,000,000
Total borrowing capacity (1)	$ 750,000,000	$ 600,000,000
Interest rate (percent)	2.24%	1.82%
Facility fee-annual rate (percent)	0.20%	0.20%
Maturity date	Jul. 1, 2022	Jul. 1, 2019
Contingent additional borrowings	$ 600,000,000
Variable rate (percent)		1.05%
Unamortized deferred financing costs	$ 6,300,000	$ 3,300,000
London Interbank Offered Rate (LIBOR) [Member] | Kilroy Realty, L.P. [Member] | Revolving Credit Facility [Member]
Terms of the Credit Facility
Variable rate (percent)	1.00%	1.05%
London Interbank Offered Rate (LIBOR) [Member] | Kilroy Realty, L.P. [Member] | Line of Credit [Member]
Terms of the Credit Facility
Variable rate (percent)		1.10%
$150 Million Term Loan Facility [Member] | Kilroy Realty, L.P. [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Unsecured debt, net (Notes 5 and 11)	$ 0	$ 150,000,000
Terms of the Credit Facility
Remaining borrowing capacity	150,000,000	$ 0
Total borrowing capacity (1)	$ 150,000,000
Facility fee-annual rate (percent)	0.20%	0.00%
Maturity date	Jul. 1, 2022	Jul. 1, 2019
Unamortized deferred financing costs	$ 1,200,000	$ 700,000
$150 Million Term Loan Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Kilroy Realty, L.P. [Member] | Line of Credit [Member]
Terms of the Credit Facility
Variable rate (percent)	1.15%

Secured and Unsecured Debt of50

Secured and Unsecured Debt of the Operating Partnership - Unsecured Term Loan Facility (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Unsecured debt, net	$ 1,909,381,000	$ 1,847,351,000
Total borrowing capacity		150,000,000
Kilroy Realty, L.P. [Member]
Debt Instrument [Line Items]
Unsecured debt, net	1,909,381,000	$ 1,847,351,000
Unamortized deferred financing costs	10,900,000
Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member] | Kilroy Realty, L.P. [Member]
Debt Instrument [Line Items]
Variable rate (percent)		1.10%
Line of Credit [Member] | $150 Million Term Loan Facility [Member] | Kilroy Realty, L.P. [Member]
Debt Instrument [Line Items]
Unsecured debt, net	0	$ 150,000,000
Remaining borrowing capacity	150,000,000	$ 0
Total borrowing capacity	$ 150,000,000
Debt instrument, interest rate, effective percentage	2.33%	1.85%
Facility fee-annual rate (percent)	0.20%	0.00%
Maturity date	Jul. 1, 2022	Jul. 1, 2019
Minimum credit facility draw	$ 75,000,000
Unutilized borrowing capacity, fee percentage	50.00%
Unamortized deferred financing costs	$ 1,200,000	$ 700,000
Line of Credit [Member] | $150 Million Term Loan Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Kilroy Realty, L.P. [Member]
Debt Instrument [Line Items]
Variable rate (percent)	1.15%
Line of Credit [Member] | $39 Million Unsecured Term Loan Due July 2019 [Member] | Kilroy Realty, L.P. [Member]
Debt Instrument [Line Items]
Unsecured debt, net		39,000,000
Unamortized deferred financing costs		$ 200,000
Line of Credit [Member] | $39 Million Unsecured Term Loan Due July 2019 [Member] | London Interbank Offered Rate (LIBOR) [Member] | Kilroy Realty, L.P. [Member]
Debt Instrument [Line Items]
Variable rate (percent)		1.15%

Secured and Unsecured Debt of51

Secured and Unsecured Debt of the Operating Partnership - Debt Maturities (Details) - Kilroy Realty, L.P. [Member] $ in Thousands	Sep. 30, 2017USD ($)
Stated debt maturities and scheduled amortization payments, excluding debt discounts
Remaining 2,017	$ 1,545
2,018	451,669
2,019	76,309
2,020	255,137
2,021	5,342
Thereafter	1,659,023
Total debt	2,449,025
Unamortized debt issuance costs	(10,900)
Unsecured Senior Notes [Member]
Stated debt maturities and scheduled amortization payments, excluding debt discounts
Unamortized discount	(6,000)
Secured debt [Member]
Stated debt maturities and scheduled amortization payments, excluding debt discounts
Unamortized premium	$ 3,000

Secured and Unsecured Debt of52

Secured and Unsecured Debt of the Operating Partnership - Capitalized Interest and Loan Fees (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Capitalized Interest and Loan Fees [Line Items]
Interest expense	$ 16,151	$ 14,976	$ 51,476	$ 41,189
Kilroy Realty, L.P. [Member]
Capitalized Interest and Loan Fees [Line Items]
Gross interest expense	28,331	26,184	84,577	79,027
Capitalized interest and deferred financing costs	(12,180)	(11,208)	(33,101)	(37,838)
Interest expense	$ 16,151	$ 14,976	$ 51,476	$ 41,189

Noncontrolling Interests on t53

Noncontrolling Interests on the Company's Consolidated Financial Statements - Common Units of the Operating Partnership (Details) - USD ($) $ / shares in Units, $ in Millions	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Noncontrolling Interest [Line Items]
Common general partnership interest in the Operating Partnership	97.90%	97.50%	97.20%
Common limited partnership interest in the Operating Partnership	2.10%	2.50%	2.80%
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Aggregate value upon redemption of outstanding noncontrolling common units	$ 145.6	$ 174.9
Brannan St Project [Member]
Noncontrolling Interest [Line Items]
Common stock, par value (in dollars per share)	$ 0.01
Kilroy Realty, L.P. [Member] | Capital Units [Member]
Noncontrolling Interest [Line Items]
Common units outstanding held by common limited partners	2,077,193	2,381,543	2,631,276

Stockholders' Equity of the C54

Stockholders' Equity of the Company (Details) - USD ($)	Aug. 15, 2017	Mar. 30, 2017	Jan. 13, 2017	Dec. 30, 2016	Jan. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2014
Common Stock of the Company [Abstract]
Common stock, shares issued (in shares)					4,427,500	98,382,256		98,382,256		93,219,439
Net proceeds from issuance of common stock (Note 7)					$ 308,800,000			$ 308,812,000	$ 0
At the market stock offering aggregate gross sales price of common stock											$ 300,000,000
Payments of special cash dividends			$ 184,300,000
Dividends declared per common share (in dollars per share)				$ 1.90		$ 0.425	$ 0.375000	$ 1.225	$ 1.1
Payment of special dividend			$ 36,400,000					$ 297,993,000	$ 101,542,000
Series H Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, redeemed (in shares)	4,000,000					0		0		4,000,000
Preferred stock dividend rate percentage	6.375%	6.375%						0.00%		6.375%
Preferred stock, liquidation preference (in dollars per share)	$ 25
Preferred stock liquidation preference	$ 100,000,000					$ 0		$ 0		$ 100,000,000
Series G Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, redeemed (in shares)		4,000,000				0		0		4,000,000
Preferred stock dividend rate percentage		6.875%						0.00%		6.875%
Preferred stock, liquidation preference (in dollars per share)		$ 25
Preferred stock liquidation preference		$ 100,000,000				$ 0		$ 0		$ 100,000,000
Write off of issuance costs						$ (3,700,000)		$ (7,600,000)
Common Stock [Member] | Issuance of Equity - at the market offering [Member]
Common Stock of the Company [Abstract]
Common stock, shares issued (in shares)						2,459,165		2,459,165
At the market stock offering aggregate gross sales price of common stock						$ 182,400,000		$ 182,400,000
At the market stock offering remaining amount available for issuance						$ 117,600,000		$ 117,600,000

Partners' Capital of the Oper55

Partners' Capital of the Operating Partnership (Details) - USD ($) $ in Thousands	Aug. 15, 2017	Mar. 30, 2017	Jan. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Class of Stock [Line Items]
Common stock, shares issued (in shares)			4,427,500	98,382,256		93,219,439
Net proceeds from issuance of common stock (Note 7)			$ 308,800	$ 308,812	$ 0
General Partners' Capital Account [Abstract]
Company owned general partnership interest				97.90%	97.20%	97.50%
Ownership interest of noncontrolling interest				2.10%	2.80%	2.50%
Series H Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, redeemed (in units)	4,000,000			0		4,000,000
Preferred stock dividend rate percentage	6.375%	6.375%		0.00%		6.375%
Series G Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, redeemed (in units)		4,000,000		0		4,000,000
Preferred stock dividend rate percentage		6.875%		0.00%		6.875%
Kilroy Realty, L.P. [Member] | Series G Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, redeemed (in units)		4,000,000
Preferred stock dividend rate percentage		6.875%
Kilroy Realty, L.P. [Member] | Capital Units [Member]
General Partners' Capital Account [Abstract]
Company owned common units in the Operating Partnership				98,382,256	92,272,492	93,219,439
Noncontrolling common units of the Operating Partnership				2,077,193	2,631,276	2,381,543

Share-Based Compensation (Detai

Share-Based Compensation (Details Textual) $ / shares in Units, $ in Millions	Feb. 24, 2017USD ($)$ / shares	Jan. 28, 2016shares	Feb. 28, 2017USD ($)shares	Sep. 30, 2017USD ($)plan$ / sharesshares	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)plan$ / sharesshares	Sep. 30, 2016USD ($)shares	Feb. 03, 2017$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share-based incentive compensation plans | plan				1		1
Share-based compensation expense | $				$ 6.4	$ 6.8	$ 19	$ 19.3
Share-based compensation expense capitalized | $				1.7	$ 1.5	5.4	$ 4
Share-based compensation not yet recognized | $				$ 30.9		$ 30.9
Share-based compensation not yet recognized period of recognition						1 year 11 months
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		229,976
2017 Performance-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			130,956
Percentage of shares granted			57.00%
Vesting period			3 years
Number of shares issuable per RSU		1
Grant date fair value | $	$ 10.3
Grant date fair value (in dollars per share) | $ / shares						$ 80.89
Remaining expected life, including future volatility						5 years 7 months
Remaining expected life						2 years 10 months
2017 Time-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			99,020
Percentage of shares granted			43.00%
Vesting period			3 years
Closing share price (in dollars per share) | $ / shares	$ 77.16							$ 73.30
Kilroy Realty 2006 Incentive Award Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant				2,004,127		2,004,127
Market Measure-Based RSU Estimate of Probable [Member] | 2017 Performance-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance				130,956		130,956
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise of stock options (Note 9) (in shares)						282,000	51,000
Share-based compensation, exercise price (in dollars per share) | $ / shares				$ 42.61		$ 42.61
Share-based compensation, stock options outstanding				29,500		29,500
Nonvested Restricted Stock Units R S U [Member] | 2017 Time-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value | $			$ 7.5

Share-Based Compensation (Det57

Share-Based Compensation (Details) - 2017 Performance-Based RSUs [Member]	9 Months Ended
	Sep. 30, 2017$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value (in dollars per share)	$ 80.89
Expected share price volatility	21.00%
Risk-free interest rate	1.39%
Remaining expected life	2 years 10 months

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	Sep. 30, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
Commitments	$ 755
Accrued environmental remediation liabilities	$ 27.1

Fair Value Measurements and D59

Fair Value Measurements and Disclosures (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Fair value adjustment of marketable securities and deferred compensation plan liability
Net gain on marketable securities	$ 536	$ 481	$ 1,719	$ 867
Fair Value (Level 1) [Member]
Assets and Liabilities Reported at Fair Value
Marketable securities	$ 18,851		$ 18,851		$ 14,773

Fair Value Measurements and D60

Fair Value Measurements and Disclosures (Details 1) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2015
Carrying Value [Member] | Secured debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt	$ 465,828	$ 472,772
Carrying Value [Member] | Unsecured Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt	1,909,381	1,847,351
Carrying Value [Member] | Line of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt	60,000		$ 0
Fair Value (Level 2) [Member] | Fair Value [Member] | Secured debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt	467,968	469,234
Fair Value (Level 2) [Member] | Fair Value [Member] | Unsecured Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt	1,983,737	$ 1,900,487
Fair Value (Level 2) [Member] | Fair Value [Member] | Line of Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt	$ 60,087		$ 0

Net Income Available to Commo61

Net Income Available to Common Stockholders Per Share of the Company (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net income attributable to Kilroy Realty Corporation	$ 71,110	$ 53,895	$ 136,083	$ 261,050
Total preferred dividends	(4,552)	(3,313)	(13,363)	(9,938)
Allocation to participating securities (1)	(501)	(426)	(1,460)	(1,244)
Numerator for basic and diluted net income available to common stockholders	$ 66,057	$ 50,156	$ 121,260	$ 249,868
Denominator:
Weighted average common shares outstanding – basic (in shares) (Note 12)	98,352,139	92,227,016	98,008,780	92,220,522
Effect of dilutive securities (in shares)	559,473	693,390	582,268	611,016
Diluted weighted average vested shares and common share equivalents outstanding (in shares)	98,911,612	92,920,406	98,591,048	92,831,538
Basic earnings per share:
Net income available to common stockholders per share (in dollars per share)	$ 0.67	$ 0.54	$ 1.24	$ 2.71
Diluted earnings per share:
Net income available to common stockholders per share (in dollars per share)	$ 0.67	$ 0.54	$ 1.23	$ 2.69

Net Income Available to Commo62

Net Income Available to Common Unitholders Per Unit of the Operating Partnership (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net income attributable to Kilroy Realty, L.P.	$ 71,110	$ 53,895	$ 136,083	$ 261,050
Total preferred dividends	(4,552)	(3,313)	(13,363)	(9,938)
Allocation to participating securities (1)	(501)	(426)	(1,460)	(1,244)
Numerator for basic and diluted net income available to common stockholders	$ 66,057	$ 50,156	$ 121,260	$ 249,868
Denominator:
Weighted average common units outstanding - basic (in units) (Note 13)	98,352,139	92,227,016	98,008,780	92,220,522
Effect of dilutive securities (in units)	559,473	693,390	582,268	611,016
Diluted weighted average vested shares and common share equivalents outstanding (in shares)	98,911,612	92,920,406	98,591,048	92,831,538
Basic earnings per unit:
Net income available to common stockholders per share (in dollars per share)	$ 0.67	$ 0.54	$ 1.24	$ 2.71
Diluted earnings per unit:
Net income available to common stockholders per share (in dollars per share)	$ 0.67	$ 0.54	$ 1.23	$ 2.69
Kilroy Realty, L.P. [Member]
Numerator:
Net income attributable to Kilroy Realty, L.P.	$ 72,402	$ 55,254	$ 138,427	$ 266,677
Total preferred dividends	(4,552)	(3,313)	(13,363)	(9,938)
Allocation to participating securities (1)	(501)	(426)	(1,460)	(1,244)
Numerator for basic and diluted net income available to common stockholders	$ 67,349	$ 51,515	$ 123,604	$ 255,495
Denominator:
Weighted average common units outstanding - basic (in units) (Note 13)	100,429,332	94,858,292	100,160,595	94,630,183
Effect of dilutive securities (in units)	559,473	693,390	582,268	611,016
Diluted weighted average vested shares and common share equivalents outstanding (in shares)	100,988,805	95,551,682	100,742,863	95,241,199
Basic earnings per unit:
Net income available to common stockholders per share (in dollars per share)	$ 0.67	$ 0.54	$ 1.23	$ 2.70
Diluted earnings per unit:
Net income available to common stockholders per share (in dollars per share)	$ 0.67	$ 0.54	$ 1.23	$ 2.68

Supplemental Cash Flow Inform63

Supplemental Cash Flow Information of the Company (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
SUPPLEMENTAL CASH FLOWS INFORMATION:
Cash paid for interest, net of capitalized interest of $31,880 and $36,468 as of September 30, 2017 and 2016, respectively	$ 46,878	$ 42,858
Interest capitalized	31,880	36,468
NON-CASH INVESTING TRANSACTIONS:
Accrual for expenditures for operating properties and development properties	104,409	77,161
Tenant improvements funded directly by tenants	10,361	16,803
Assumption of accrued liabilities in connection with acquisitions	0	4,911
NON-CASH FINANCING TRANSACTIONS:
Accrual of dividends and distributions payable to common stockholders and common unitholders	43,324	36,109
Accrual of dividends and distributions payable to preferred stockholders and preferred unitholders	0	1,656
Exchange of common units of the Operating Partnership into shares of the Company’s common stock	10,939	39
Issuance of common units of the Operating Partnership in connection with an acquisition	0	48,033
Secured debt assumed by buyers in connection with land dispositions	$ 0	$ 2,322

Supplemental Cash Flow Inform64

Supplemental Cash Flow Information of the Company - Reconciliation of cash and cash equivalents and restricted cash (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents at beginning of period	$ 193,418	$ 250,523	$ 56,508
Restricted cash at beginning of period	56,711	57,501	696
Cash and cash equivalents and restricted cash, beginning of period	250,129	308,024	57,204
Cash and cash equivalents at end of period	64,954	193,418	250,523
Restricted cash at end of period	179,276	56,711	57,501
Cash and cash equivalents and restricted cash, end of period	$ 244,230	$ 250,129	$ 308,024

Supplemental Cash Flow Inform65

Supplemental Cash Flow Information of the Operating Partnership (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
SUPPLEMENTAL CASH FLOWS INFORMATION:
Cash paid for interest, net of capitalized interest of $31,880 and $36,468 as of September 30, 2017 and 2016, respectively	$ 46,878	$ 42,858
Interest capitalized	31,880	36,468
NON-CASH INVESTING TRANSACTIONS:
Accrual for expenditures for operating properties and development properties	104,409	77,161
Tenant improvements funded directly by tenants	10,361	16,803
Assumption of accrued liabilities in connection with acquisitions	0	4,911
NON-CASH FINANCING TRANSACTIONS:
Accrual of distributions payable to common unitholders	43,324	36,109
Accrual of distributions payable to preferred unitholders	0	1,656
Issuance of common units of the Operating Partnership in connection with an acquisition	0	48,033
Secured debt assumed by buyers in connection with land dispositions	0	2,322
Kilroy Realty, L.P. [Member]
SUPPLEMENTAL CASH FLOWS INFORMATION:
Cash paid for interest, net of capitalized interest of $31,880 and $36,468 as of September 30, 2017 and 2016, respectively	46,878	42,858
Interest capitalized	31,880	36,468
NON-CASH INVESTING TRANSACTIONS:
Accrual for expenditures for operating properties and development properties	104,409	77,161
Tenant improvements funded directly by tenants	10,361	16,803
Assumption of accrued liabilities in connection with acquisitions	0	4,911
NON-CASH FINANCING TRANSACTIONS:
Accrual of distributions payable to common unitholders	43,324	36,109
Accrual of distributions payable to preferred unitholders	0	1,656
Issuance of common units of the Operating Partnership in connection with an acquisition	0	48,033
Secured debt assumed by buyers in connection with land dispositions	$ 0	$ 2,322

Supplemental Cash Flow Inform66

Supplemental Cash Flow Information of the Operating Partnership - Reconciliation of cash and cash equivalents and restricted cash (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Other Significant Noncash Transactions [Line Items]
Cash and cash equivalents at beginning of period	$ 193,418	$ 250,523	$ 56,508
Restricted cash at beginning of period	56,711	57,501	696
Cash and cash equivalents and restricted cash, beginning of period	250,129	308,024	57,204
Cash and cash equivalents at end of period	64,954	193,418	250,523
Restricted cash at end of period	179,276	56,711	57,501
Cash and cash equivalents and restricted cash, end of period	244,230	250,129	308,024
Kilroy Realty, L.P. [Member]
Other Significant Noncash Transactions [Line Items]
Cash and cash equivalents at beginning of period	193,418	250,523	56,508
Restricted cash at beginning of period	56,711	57,501	696
Cash and cash equivalents and restricted cash, beginning of period	250,129	308,024	57,204
Cash and cash equivalents at end of period	64,954	193,418	250,523
Restricted cash at end of period	179,276	56,711	57,501
Cash and cash equivalents and restricted cash, end of period	$ 244,230	$ 250,129	$ 308,024

Subsequent Events (Details)

Subsequent Events (Details) $ in Thousands	Oct. 18, 2017USD ($)	Oct. 10, 2017USD ($)a	Jan. 13, 2017USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)
Subsequent Event [Line Items]
Payment of special dividend			$ 36,400	$ 297,993	$ 101,542
Subsequent Event [Member]
Subsequent Event [Line Items]
Payment of special dividend	$ 43,300
Subsequent Event [Member] | Little Italy, Sand Diego, California [Member]
Subsequent Event [Line Items]
Area of land | a		1.2
Cash payment		$ 19,400