Kilroy Realty (KRC) 10-Q 25 Oct 19 2019 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2019	Oct. 18, 2019
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	1-12675
Entity Registrant Name	KILROY REALTY CORPORATION
Entity Incorporation, State Code	MD
Entity Tax Identification Number	95-4598246
Entity Address, Address Line One	12200 W. Olympic Boulevard
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Los Angeles
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	90064
City Area Code	310
Local Phone Number	481-8400
Title of 12(b) Security	Common Stock, $.01 par value
Security Exchange Name	NYSE
Trading Symbol	KRC
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		106,011,916
Entity Central Index Key	0001025996
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false
Kilroy Realty L.P. [Member]
Entity Information [Line Items]
Entity File Number	000-54005
Entity Registrant Name	KILROY REALTY, L.P.
Entity Incorporation, State Code	DE
Entity Tax Identification Number	95-4612685
Title of 12(g) Security	Common Units Representing Limited Partnership Interests
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Central Index Key	0001493976

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
REAL ESTATE ASSETS:
Land and improvements	$ 1,315,448	$ 1,160,138
Buildings and improvements	5,770,226	5,207,984
Undeveloped land and construction in progress	1,892,169	2,058,510
Total real estate assets held for investment	8,977,843	8,426,632
Accumulated depreciation and amortization	(1,505,785)	(1,391,368)
Total real estate assets held for investment, net	7,472,058	7,035,264
REAL ESTATE ASSETS AND OTHER ASSETS HELD FOR SALE, NET (Note 3)	77,751
CASH AND CASH EQUIVALENTS	297,620	51,604
RESTRICTED CASH	6,300	119,430
MARKETABLE SECURITIES (Note 12)	26,188	21,779
CURRENT RECEIVABLES, NET (Note 1)	34,116	20,176
DEFERRED RENT RECEIVABLES, NET (Note 1)	314,812	267,007
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET (Note 1)	202,063	197,574
RIGHT OF USE GROUND LEASE ASSETS (Notes 1 and 11)	83,200
PREPAID EXPENSES AND OTHER ASSETS, NET (Note 4)	109,707	52,873
TOTAL ASSETS	8,623,815	7,765,707
LIABILITIES:
Secured debt, net (Notes 5 and 12)	259,027	335,531
Unsecured debt, net (Notes 5 and 12)	3,048,209	2,552,070
Unsecured line of credit (Notes 5 and 12)	0	45,000
Accounts payable, accrued expenses and other liabilities	439,081	374,415
Ground lease liabilities (Notes 1 and 11)	87,617
Accrued dividends and distributions (Note 17)	53,205	47,559
Deferred revenue and acquisition-related intangible liabilities, net	134,828	149,646
Rents received in advance and tenant security deposits	57,428	60,225
Liabilities and deferred revenue of real estate assets held for sale (Note 3)	4,911	0
Total liabilities	4,084,306	3,564,446
COMMITMENTS AND CONTINGENCIES (Note 11)
Stockholders’ Equity (Note 6):
Common stock, $.01 par value, 150,000,000 shares authorized, 106,011,916 and 100,746,988 shares issued and outstanding, respectively	1,060	1,007
Additional paid-in capital	4,342,296	3,976,953
Distributions in excess of earnings (Note 1)	(78,707)	(48,053)
Total stockholders’ equity	4,264,649	3,929,907
Noncontrolling Interests (Notes 1 and 7):
Common units of the Operating Partnership	81,393	78,991
Noncontrolling interests in consolidated property partnerships	193,467	192,363
Total noncontrolling interests	274,860	271,354
Total equity	4,539,509	4,201,261
TOTAL LIABILITIES AND EQUITY (CAPITAL)	$ 8,623,815	$ 7,765,707

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	106,011,916	100,746,988
Common stock, shares outstanding (in shares)	106,011,916	100,746,988

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
REVENUES (Note 1)
Revenue	$ 215,525	$ 186,562	$ 617,219	$ 556,456
EXPENSES
Real estate taxes	19,998	17,462	56,563	52,421
Provision for bad debts (Note 1)	0	1,338	0	6,714
Ground leases (Notes 1 and 11)	2,049		6,135
Ground leases (Notes 1 and 11)		1,579		4,726
General and administrative expenses	22,576	19,277	65,774	56,599
Leasing costs (Note 1)	1,192	0	5,599	0
Depreciation and amortization	69,230	62,700	203,617	189,421
Total expenses	156,353	137,519	455,681	409,282
OTHER (EXPENSES) INCOME
Interest income and other net investment gain (Note 12)	761	342	3,205	1,147
Interest expense (Note 5)	(11,635)	(11,075)	(34,605)	(37,285)
Gains on sales of depreciable operating properties (Note 3)	0	0	7,169	0
Total other (expenses) income	(10,874)	(10,733)	(24,231)	(36,138)
NET INCOME	48,298	38,310	137,307	111,036
Net income attributable to noncontrolling common units of the Operating Partnership	(852)	(691)	(2,423)	(2,008)
Net income attributable to noncontrolling interests in consolidated property partnerships	(3,600)	(3,219)	(11,941)	(10,833)
Total income attributable to noncontrolling interests	(4,452)	(3,910)	(14,364)	(12,841)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS (UNITHOLDERS)	$ 43,846	$ 34,400	$ 122,943	$ 98,195
Net income available to common stockholders per share – basic (in dollars per share)	$ 0.41	$ 0.34	$ 1.19	$ 0.97
Net income available to common stockholders per share – diluted (in dollars per share)	$ 0.41	$ 0.33	$ 1.18	$ 0.97
Weighted average common shares outstanding – basic (in shares)	104,841,176	100,676,778	102,252,739	99,711,312
Weighted average common shares outstanding – diluted (in shares)	105,359,904	101,228,334	102,872,436	100,208,645
Rental income [Member]
REVENUES (Note 1)
Revenue	$ 212,321	$ 162,288	$ 609,332	$ 489,674
Tenant reimbursements [Member]
REVENUES (Note 1)
Revenue	0	21,754	0	60,471
Other property income [Member]
REVENUES (Note 1)
Revenue	3,204	2,520	7,887	6,311
Property [Member]
EXPENSES
Property expenses (Note 1)	$ 41,308	$ 35,163	$ 117,993	$ 99,401

CONSOLIDATED STATEMENTS OF EQUI

CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Distributions in Excess of Earnings [Member]	Total Stockholders' Equity [Member]	Noncontrolling Interests [Member]
Beginning balance (in shares) at Dec. 31, 2017		98,620,333
Beginning balance at Dec. 31, 2017	$ 3,960,316	$ 986	$ 3,822,492	$ (122,685)	$ 3,700,793	$ 259,523
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	40,971			36,246	36,246	4,725
Issuance of share-based compensation awards	1,864		1,864		1,864
Non-cash amortization of share-based compensation	5,094		5,094		5,094
Settlement of restricted stock units for shares of common stock (in shares)		405,067
Settlement of restricted stock units for shares of common stock	0	$ 4	(4)
Repurchase and cancellation of common stock, stock options, and restricted stock units (in shares)		(192,195)
Repurchase and cancellation of common stock, stock options, and restricted stock units	(13,642)	$ (2)	(13,640)		(13,642)
Exchange of common units of the Operating Partnership (in shares)		6,503
Exchange of common units of the Operating Partnership	0		244		244	(244)
Distributions to noncontrolling interests in consolidated property partnerships	(2,177)					(2,177)
Adjustment for noncontrolling interest	0		335		335	(335)
Dividends declared per common share and common unit	(44,954)			(44,075)	(44,075)	(879)
Ending balance (in shares) at Mar. 31, 2018		98,839,708
Ending balance at Mar. 31, 2018	3,947,472	$ 988	3,816,385	(130,514)	3,686,859	260,613
Beginning balance (in shares) at Dec. 31, 2017		98,620,333
Beginning balance at Dec. 31, 2017	3,960,316	$ 986	3,822,492	(122,685)	3,700,793	259,523
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	111,036
Ending balance (in shares) at Sep. 30, 2018		100,746,988
Ending balance at Sep. 30, 2018	4,074,919	$ 1,007	3,965,405	(161,654)	3,804,758	270,161
Beginning balance (in shares) at Mar. 31, 2018		98,839,708
Beginning balance at Mar. 31, 2018	3,947,472	$ 988	3,816,385	(130,514)	3,686,859	260,613
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	31,755			27,549	27,549	4,206
Issuance of common stock (in shares)		1,719,195
Issuance of common stock	124,147	$ 17	124,130		124,147
Issuance of share-based compensation awards	589		589		589
Non-cash amortization of share-based compensation	11,503		11,503		11,503
Exercise of stock options (in shares)		1,000
Exercise of stock options	41		41		41
Exchange of common units of the Operating Partnership	0	$ 1			1	(1)
Distributions to noncontrolling interests in consolidated property partnerships	(4,288)					(4,288)
Adjustment for noncontrolling interest	0		(1,359)		(1,359)	1,359
Dividends declared per common share and common unit	(47,346)			(46,403)	(46,403)	(943)
Ending balance (in shares) at Jun. 30, 2018		100,559,903
Ending balance at Jun. 30, 2018	4,063,873	$ 1,006	3,951,289	(149,368)	3,802,927	260,946
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	38,310			34,400	34,400	3,910
Issuance of common stock (in shares)		98,000
Issuance of common stock	6,597	$ 1	6,596		6,597
Issuance of share-based compensation awards	845		845		845
Non-cash amortization of share-based compensation	8,081		8,081		8,081
Settlement of restricted stock units for shares of common stock (in shares)		83,287
Settlement of restricted stock units for shares of common stock	0
Repurchase and cancellation of common stock, stock options, and restricted stock units (in shares)		(39,605)
Repurchase and cancellation of common stock, stock options, and restricted stock units	(2,911)		(2,911)		(2,911)
Exchange of common units of the Operating Partnership (in shares)		45,403
Exchange of common units of the Operating Partnership	0		1,717		1,717	(1,717)
Contributions from noncontrolling interests in consolidated property partnerships	8,273					8,273
Distributions to noncontrolling interests in consolidated property partnerships	(541)					(541)
Adjustment for noncontrolling interest	0		(212)		(212)	212
Dividends declared per common share and common unit	(47,608)			(46,686)	(46,686)	(922)
Ending balance (in shares) at Sep. 30, 2018		100,746,988
Ending balance at Sep. 30, 2018	$ 4,074,919	$ 1,007	3,965,405	(161,654)	3,804,758	270,161
Beginning balance (in shares) at Dec. 31, 2018	100,746,988	100,746,988
Beginning balance at Dec. 31, 2018	$ 4,201,261	$ 1,007	3,976,953	(48,053)	3,929,907	271,354
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	41,794			36,903	36,903	4,891
Issuance of share-based compensation awards	2,210		2,210		2,210
Non-cash amortization of share-based compensation	8,817		8,817		8,817
Settlement of restricted stock units for shares of common stock (in shares)		393,240
Settlement of restricted stock units for shares of common stock	0	$ 4	(4)
Repurchase and cancellation of common stock, stock options, and restricted stock units (in shares)		(175,204)
Repurchase and cancellation of common stock, stock options, and restricted stock units	(12,130)	$ (1)	(12,129)		(12,130)
Exchange of common units of the Operating Partnership (in shares)		2,000
Exchange of common units of the Operating Partnership	0		78		78	(78)
Distributions to noncontrolling interests in consolidated property partnerships	(6,309)					(6,309)
Adjustment for noncontrolling interest	0		279		279	(279)
Dividends declared per common share and common unit	(49,315)			(48,394)	(48,394)	(921)
Ending balance (in shares) at Mar. 31, 2019		100,967,024
Ending balance at Mar. 31, 2019	$ 4,183,182	$ 1,010	3,976,204	(62,690)	3,914,524	268,658
Beginning balance (in shares) at Dec. 31, 2018	100,746,988	100,746,988
Beginning balance at Dec. 31, 2018	$ 4,201,261	$ 1,007	3,976,953	(48,053)	3,929,907	271,354
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 137,307
Ending balance (in shares) at Sep. 30, 2019	106,011,916	106,011,916
Ending balance at Sep. 30, 2019	$ 4,539,509	$ 1,060	4,342,296	(78,707)	4,264,649	274,860
Beginning balance (in shares) at Mar. 31, 2019		100,967,024
Beginning balance at Mar. 31, 2019	4,183,182	$ 1,010	3,976,204	(62,690)	3,914,524	268,658
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	47,215			42,194	42,194	5,021
Issuance of share-based compensation awards	820		820		820
Non-cash amortization of share-based compensation	8,732		8,732		8,732
Exercise of stock options (in shares)		1,500
Exercise of stock options	64		64		64
Settlement of restricted stock units for shares of common stock (in shares)		16,270
Settlement of restricted stock units for shares of common stock	0
Repurchase and cancellation of common stock, stock options, and restricted stock units (in shares)		(12,759)
Repurchase and cancellation of common stock, stock options, and restricted stock units	(793)		(793)		(793)
Distributions to noncontrolling interests in consolidated property partnerships	(1,487)					(1,487)
Adjustment for noncontrolling interest	0		(160)		(160)	160
Dividends declared per common share and common unit	(50,830)			(49,849)	(49,849)	(981)
Ending balance (in shares) at Jun. 30, 2019		100,972,035
Ending balance at Jun. 30, 2019	4,186,903	$ 1,010	3,984,867	(70,345)	3,915,532	271,371
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	48,298			43,846	43,846	4,452
Issuance of common stock (in shares)		5,000,000
Issuance of common stock	353,904	$ 50	353,854		353,904
Issuance of share-based compensation awards	839		839		839
Non-cash amortization of share-based compensation	6,808		6,808		6,808
Exercise of stock options (in shares)		15,000
Exercise of stock options	639		639		639
Settlement of restricted stock units for shares of common stock (in shares)		46,149
Settlement of restricted stock units for shares of common stock	0	$ 1	(1)
Repurchase and cancellation of common stock, stock options, and restricted stock units (in shares)		(21,268)
Repurchase and cancellation of common stock, stock options, and restricted stock units	(1,652)	$ (1)	(1,651)		(1,652)
Distributions to noncontrolling interests in consolidated property partnerships	(3,041)					(3,041)
Adjustment for noncontrolling interest	0		(3,059)		(3,059)	3,059
Dividends declared per common share and common unit	$ (53,189)			(52,208)	(52,208)	(981)
Ending balance (in shares) at Sep. 30, 2019	106,011,916	106,011,916
Ending balance at Sep. 30, 2019	$ 4,539,509	$ 1,060	$ 4,342,296	$ (78,707)	$ 4,264,649	$ 274,860

CONSOLIDATED STATEMENTS OF EQ_2

CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Statement of Stockholders' Equity [Abstract]
Dividends declared per common share and common unit (in dollars per share)	$ 0.485	$ 0.485	$ 0.455	$ 0.455	$ 0.455	$ 0.425

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 137,307	$ 111,036
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of real estate assets and leasing costs	199,967	186,242
Depreciation of non-real estate furniture, fixtures and equipment	3,650	3,179
(Recoveries of) provision for bad debts and write-offs (Note 1)	(3,685)	6,714
Non-cash amortization of share-based compensation awards	20,200	18,901
Non-cash amortization of deferred financing costs and debt discounts and premiums	911	816
Non-cash amortization of net below market rents	(6,241)	(7,647)
Gain on sale of depreciable operating properties (Note 3)	(7,169)	0
Non-cash amortization of deferred revenue related to tenant-funded tenant improvements	(14,947)	(13,680)
Straight-line rents	(48,725)	(16,293)
Amortization of right of use ground lease assets	453	0
Net change in other operating assets	(24,752)	(9,163)
Net change in other operating liabilities	44,421	37,110
Net cash provided by operating activities	301,390	317,215
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for development properties and undeveloped land	(554,951)	(311,347)
Expenditures for acquisition of undeveloped land (Note 2)	(40,027)	(311,299)
Expenditures for operating properties and other capital assets	(99,479)	(107,825)
Expenditures for acquisition of operating properties	0	(111,029)
Net proceeds received from dispositions (Note 3)	17,271	0
Net (increase) decrease in acquisition-related deposits (Note 4)	(49,998)
Net (increase) decrease in acquisition-related deposits (Note 4)		21,000
Proceeds received from repayment of note receivable	0	15,100
Net cash used in investing activities	(727,184)	(805,400)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of common stock	353,904	130,744
Proceeds from the issuance of unsecured debt (Note 5)	499,390	50,000
Borrowings on unsecured revolving credit facility (Note 5)	630,000	645,000
Repayments on unsecured revolving credit facility (Note 5)	(675,000)	(285,000)
Borrowings on unsecured debt	0	120,000
Principal payments and repayments of secured debt (Note 5)	(75,844)	(2,670)
Financing costs	(5,548)	(2,278)
Repurchase of common stock and restricted stock units	(14,269)	(16,553)
Proceeds from exercise of stock options	703	41
Distributions to noncontrolling interests in consolidated property partnerships	(10,844)	(7,014)
Contributions from noncontrolling interests in consolidated property partnerships	0	8,273
Dividends and distributions paid to common stockholders and common unitholders	(143,812)	(132,639)
Net cash provided by financing activities	558,680	507,904
Net increase in cash and cash equivalents and restricted cash	132,886	19,719
Cash and cash equivalents and restricted cash, beginning of period	171,034	66,798
Cash and cash equivalents and restricted cash, end of period	$ 303,920	$ 86,517

CONSOLIDATED BALANCE SHEETS (KI

CONSOLIDATED BALANCE SHEETS (KILROY REALTY, L.P.) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
REAL ESTATE ASSETS:
Land and improvements	$ 1,315,448	$ 1,160,138
Buildings and improvements	5,770,226	5,207,984
Undeveloped land and construction in progress	1,892,169	2,058,510
Total real estate assets held for investment	8,977,843	8,426,632
Accumulated depreciation and amortization	(1,505,785)	(1,391,368)
Total real estate assets held for investment, net	7,472,058	7,035,264
REAL ESTATE ASSETS AND OTHER ASSETS HELD FOR SALE, NET (Note 3)	77,751
CASH AND CASH EQUIVALENTS	297,620	51,604
RESTRICTED CASH	6,300	119,430
MARKETABLE SECURITIES (Note 12)	26,188	21,779
CURRENT RECEIVABLES, NET (Note 1)	34,116	20,176
DEFERRED RENT RECEIVABLES, NET (Note 1)	314,812	267,007
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET (Note 1)	202,063	197,574
RIGHT OF USE GROUND LEASE ASSETS (Notes 1 and 11)	83,200
PREPAID EXPENSES AND OTHER ASSETS, NET (Note 4)	109,707	52,873
TOTAL ASSETS	8,623,815	7,765,707
LIABILITIES:
Secured debt, net (Notes 5 and 12)	259,027	335,531
Unsecured debt, net (Notes 5 and 12)	3,048,209	2,552,070
Unsecured line of credit (Notes 5 and 12)	0	45,000
Accounts payable, accrued expenses and other liabilities	439,081	374,415
Ground lease liabilities (Notes 1 and 11)	87,617
Accrued distributions (Note 17)	53,205	47,559
Deferred revenue and acquisition-related intangible liabilities, net	134,828	149,646
Rents received in advance and tenant security deposits	57,428	60,225
Liabilities and deferred revenue of real estate assets held for sale (Note 3)	4,911	0
Total liabilities	4,084,306	3,564,446
COMMITMENTS AND CONTINGENCIES
CAPITAL:
TOTAL LIABILITIES AND EQUITY (CAPITAL)	8,623,815	7,765,707
Kilroy Realty L.P. [Member]
REAL ESTATE ASSETS:
Land and improvements	1,315,448	1,160,138
Buildings and improvements	5,770,226	5,207,984
Undeveloped land and construction in progress	1,892,169	2,058,510
Total real estate assets held for investment	8,977,843	8,426,632
Accumulated depreciation and amortization	(1,505,785)	(1,391,368)
Total real estate assets held for investment, net	7,472,058	7,035,264
REAL ESTATE ASSETS AND OTHER ASSETS HELD FOR SALE, NET (Note 3)	77,751
CASH AND CASH EQUIVALENTS	297,620	51,604
RESTRICTED CASH	6,300	119,430
MARKETABLE SECURITIES (Note 12)	26,188	21,779
CURRENT RECEIVABLES, NET (Note 1)	34,116	20,176
DEFERRED RENT RECEIVABLES, NET (Note 1)	314,812	267,007
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET (Note 1)	202,063	197,574
RIGHT OF USE GROUND LEASE ASSETS (Notes 1 and 11)	83,200
PREPAID EXPENSES AND OTHER ASSETS, NET (Note 4)	109,707	52,873
TOTAL ASSETS	8,623,815	7,765,707
LIABILITIES:
Secured debt, net (Notes 5 and 12)	259,027	335,531
Unsecured debt, net (Notes 5 and 12)	3,048,209	2,552,070
Unsecured line of credit (Notes 5 and 12)	0	45,000
Accounts payable, accrued expenses and other liabilities	439,081	374,415
Ground lease liabilities (Notes 1 and 11)	87,617
Accrued distributions (Note 17)	53,205	47,559
Deferred revenue and acquisition-related intangible liabilities, net	134,828	149,646
Rents received in advance and tenant security deposits	57,428	60,225
Liabilities and deferred revenue of real estate assets held for sale (Note 3)	4,911	0
Total liabilities	4,084,306	3,564,446
COMMITMENTS AND CONTINGENCIES
CAPITAL:
Common units, 106,011,916 and 100,746,988 held by the general partner and 2,023,287 and 2,025,287 held by common limited partners issued and outstanding, respectively (Note 7)	4,340,476	4,003,700
Noncontrolling interests in consolidated property partnerships and subsidiaries (Note 1)	199,033	197,561
Total capital	4,539,509	4,201,261
TOTAL LIABILITIES AND EQUITY (CAPITAL)	$ 8,623,815	$ 7,765,707

CONSOLIDATED BALANCE SHEETS (_2

CONSOLIDATED BALANCE SHEETS (KILROY REALTY, L.P.) (Parenthetical) - Common units [Member] - Kilroy Realty L.P. [Member] - shares	Sep. 30, 2019	Dec. 31, 2018
General partner, units issued	106,011,916	100,746,988
General partners, units outstanding	106,011,916	100,746,988
Limited partners, units issued	2,023,287	2,025,287
Noncontrolling common units of the Operating Partnership	2,023,287	2,025,287

CONSOLIDATED STATEMENTS OF OP_2

CONSOLIDATED STATEMENTS OF OPERATIONS (KILROY REALTY, L.P.) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
REVENUES (Note 1)
Revenue	$ 215,525	$ 186,562	$ 617,219	$ 556,456
EXPENSES
Real estate taxes	19,998	17,462	56,563	52,421
Provision for bad debts (Note 1)	0	1,338	0	6,714
Ground leases (Notes 1 and 11)	2,049		6,135
Ground leases (Note 1 and 11)		1,579		4,726
General and administrative expenses	22,576	19,277	65,774	56,599
Leasing costs (Note 1)	1,192	0	5,599	0
Depreciation and amortization	69,230	62,700	203,617	189,421
Total expenses	156,353	137,519	455,681	409,282
OTHER (EXPENSES) INCOME
Interest income and other net investment gain (Note 12)	761	342	3,205	1,147
Interest expense (Note 5)	(11,635)	(11,075)	(34,605)	(37,285)
Gains on sales of depreciable operating properties (Note 3)	0	0	7,169	0
Total other (expenses) income	(10,874)	(10,733)	(24,231)	(36,138)
NET INCOME	48,298	38,310	137,307	111,036
Net income attributable to noncontrolling interests in consolidated property partnerships and subsidiaries	(4,452)	(3,910)	(14,364)	(12,841)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS (UNITHOLDERS)	$ 43,846	$ 34,400	$ 122,943	$ 98,195
Net income available to common unitholders per unit – basic (in dollars per unit)	$ 0.41	$ 0.34	$ 1.19	$ 0.97
Net income available to common unitholders per unit – diluted (in dollars per unit)	$ 0.41	$ 0.33	$ 1.18	$ 0.97
Weighted average common shares outstanding – basic (in units)	104,841,176	100,676,778	102,252,739	99,711,312
Weighted average common units outstanding – diluted (in units)	105,359,904	101,228,334	102,872,436	100,208,645
Rental income [Member]
REVENUES (Note 1)
Revenue	$ 212,321	$ 162,288	$ 609,332	$ 489,674
Tenant reimbursements [Member]
REVENUES (Note 1)
Revenue	0	21,754	0	60,471
Other property income [Member]
REVENUES (Note 1)
Revenue	3,204	2,520	7,887	6,311
Property [Member]
EXPENSES
Property expenses	41,308	35,163	117,993	99,401
Kilroy Realty L.P. [Member]
REVENUES (Note 1)
Revenue	215,525	186,562	617,219	556,456
EXPENSES
Real estate taxes	19,998	17,462	56,563	52,421
Provision for bad debts (Note 1)	0	1,338	0	6,714
Ground leases (Notes 1 and 11)	2,049		6,135
Ground leases (Note 1 and 11)		1,579		4,726
General and administrative expenses	22,576	19,277	65,774	56,599
Leasing costs (Note 1)	1,192	0	5,599	0
Depreciation and amortization	69,230	62,700	203,617	189,421
Total expenses	156,353	137,519	455,681	409,282
OTHER (EXPENSES) INCOME
Interest income and other net investment gain (Note 12)	761	342	3,205	1,147
Interest expense (Note 5)	(11,635)	(11,075)	(34,605)	(37,285)
Gains on sales of depreciable operating properties (Note 3)	0	0	7,169	0
Total other (expenses) income	(10,874)	(10,733)	(24,231)	(36,138)
NET INCOME	48,298	38,310	137,307	111,036
Net income attributable to noncontrolling interests in consolidated property partnerships and subsidiaries	(3,709)	(3,317)	(12,309)	(11,135)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS (UNITHOLDERS)	$ 44,589	$ 34,993	$ 124,998	$ 99,901
Net income available to common unitholders per unit – basic (in dollars per unit)	$ 0.41	$ 0.34	$ 1.18	$ 0.97
Net income available to common unitholders per unit – diluted (in dollars per unit)	$ 0.41	$ 0.33	$ 1.18	$ 0.96
Weighted average common shares outstanding – basic (in units)	106,864,463	102,721,806	104,276,187	101,773,540
Weighted average common units outstanding – diluted (in units)	107,383,191	103,273,362	104,895,884	102,270,873
Kilroy Realty L.P. [Member] | Rental income [Member]
REVENUES (Note 1)
Revenue	$ 212,321	$ 162,288	$ 609,332	$ 489,674
Kilroy Realty L.P. [Member] | Tenant reimbursements [Member]
REVENUES (Note 1)
Revenue	0	21,754	0	60,471
Kilroy Realty L.P. [Member] | Other property income [Member]
REVENUES (Note 1)
Revenue	3,204	2,520	7,887	6,311
Kilroy Realty L.P. [Member] | Property [Member]
EXPENSES
Property expenses	$ 41,308	$ 35,163	$ 117,993	$ 99,401

CONSOLIDATED STATEMENTS OF CAPI

CONSOLIDATED STATEMENTS OF CAPITAL (KILROY REALTY, L.P.) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	$ 48,298	$ 47,215	$ 41,794	$ 38,310	$ 31,755	$ 40,971	$ 137,307	$ 111,036
Non-cash amortization of share-based compensation	6,808	8,732	8,817	8,081	11,503	5,094
Settlement of restricted stock units	0	0	0	0		0
Contributions from noncontrolling interests in consolidated property partnerships				8,273
Distributions to noncontrolling interests in consolidated property partnerships	(3,041)	(1,487)	(6,309)	(541)	(4,288)	(2,177)
Accounting Standards Update 2016-02 [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Opening adjustment to Partners’ Capital upon adoption of ASC 842 (Note 1)									$ (3,146)
Noncontrolling Interests [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	4,452	5,021	4,891	3,910	4,206	4,725
Contributions from noncontrolling interests in consolidated property partnerships				8,273
Distributions to noncontrolling interests in consolidated property partnerships	(3,041)	(1,487)	(6,309)	(541)	(4,288)	(2,177)
Kilroy Realty L.P. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	4,186,903	4,183,182	4,201,261	4,063,873	3,947,472	3,960,316	4,201,261	3,960,316
Net income	48,298	47,215	41,794	38,310	31,755	40,971	137,307	111,036
Issuance of common units	353,904			6,597	124,147
Issuance of share-based compensation awards	839	820	2,210	845	589	1,864
Non-cash amortization of share-based compensation	6,808	8,732	8,817	8,081	11,503	5,094
Exercise of stock options	639	64			41
Settlement of restricted stock units	0	0	0	0		0
Repurchase and cancellation of common units, stock options, and restricted stock units	(1,652)	(793)	(12,130)	(2,911)		(13,642)
Contributions from noncontrolling interests in consolidated property partnerships				8,273
Distributions to noncontrolling interests in consolidated property partnerships	(3,041)	(1,487)	(6,309)	(541)	(4,288)	(2,177)
Dividends declared per common unit	(53,189)	(50,830)	(49,315)	(47,608)	(47,346)	(44,954)
Ending balance	$ 4,539,509	$ 4,186,903	$ 4,183,182	$ 4,074,919	$ 4,063,873	$ 3,947,472	$ 4,539,509	$ 4,074,919
Kilroy Realty L.P. [Member] | Accounting Standards Update 2016-02 [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Opening adjustment to Partners’ Capital upon adoption of ASC 842 (Note 1)									(3,146)
Kilroy Realty L.P. [Member] | Partners' Capital [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)	102,995,322	102,990,311	102,772,275	102,630,593	100,910,398	100,697,526	102,772,275	100,697,526
Beginning balance	$ 3,988,538	$ 3,987,644	$ 4,003,700	$ 3,876,145	$ 3,759,196	$ 3,773,941	$ 4,003,700	$ 3,773,941
Net income	$ 44,589	42,901	37,508	$ 34,993	$ 28,015	36,893
Issuance of common units (in units)	5,000,000			98,000	1,719,195
Issuance of common units	$ 353,904			$ 6,597	$ 124,147
Issuance of share-based compensation awards	839	820	2,210	845	589	1,864
Non-cash amortization of share-based compensation	$ 6,808	$ 8,732	$ 8,817	$ 8,081	$ 11,503	$ 5,094
Exercise of stock options (in units)	15,000	1,500			1,000
Exercise of stock options	$ 639	$ 64			$ 41
Settlement of restricted stock units (in units)	46,149	16,270	393,240	83,287		405,067
Repurchase and cancellation of common units, stock options, and restricted stock units (in units)	21,268	(12,759)	(175,204)	(39,605)		(192,195)
Repurchase and cancellation of common units, stock options, and restricted stock units	$ 1,652	$ (793)	$ (12,130)	$ (2,911)		$ (13,642)
Dividends declared per common unit	$ 53,189	$ (50,830)	$ (49,315)	$ (47,608)	$ (47,346)	$ (44,954)
Ending balance (in units)	108,035,203	102,995,322	102,990,311	102,772,275	102,630,593	100,910,398	108,035,203	102,772,275
Ending balance	$ 4,340,476	$ 3,988,538	$ 3,987,644	$ 3,876,142	$ 3,876,145	$ 3,759,196	$ 4,340,476	$ 3,876,142
Kilroy Realty L.P. [Member] | Partners' Capital [Member] | Accounting Standards Update 2016-02 [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Opening adjustment to Partners’ Capital upon adoption of ASC 842 (Note 1)									$ (3,146)
Kilroy Realty L.P. [Member] | Noncontrolling Interests [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	198,365	195,538	197,561	187,728	188,276	186,375	197,561	186,375
Net income	3,709	4,314	4,286	3,317	3,740	4,078
Contributions from noncontrolling interests in consolidated property partnerships				8,273
Distributions to noncontrolling interests in consolidated property partnerships	3,041	(1,487)	(6,309)	(541)	(4,288)	(2,177)
Ending balance	$ 199,033	$ 198,365	$ 195,538	$ 198,777	$ 187,728	$ 188,276	$ 199,033	$ 198,777

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CAPITAL (KILROY REALTY, L.P.) (Parenthetical) - $ / shares	3 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Kilroy Realty L.P. [Member]
Dividends declared per common unit (in dollars per unit)	$ 0.485	$ 0.485	$ 0.455	$ 0.455	$ 0.455	$ 0.425

CONSOLIDATED STATEMENTS OF CA_3

CONSOLIDATED STATEMENTS OF CASH FLOWS (KILROY REALTY, L.P.) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 137,307	$ 111,036
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of real estate assets and leasing costs	199,967	186,242
Depreciation of non-real estate furniture, fixtures and equipment	3,650	3,179
(Recoveries of) provision for bad debts and write-offs (Note 1)	(3,685)	6,714
Non-cash amortization of share-based compensation awards	20,200	18,901
Non-cash amortization of deferred financing costs and debt discounts and premiums	911	816
Non-cash amortization of net below market rents	(6,241)	(7,647)
Gain on sale of depreciable operating properties (Note 3)	(7,169)	0
Non-cash amortization of deferred revenue related to tenant-funded tenant improvements	(14,947)	(13,680)
Straight-line rents	(48,725)	(16,293)
Amortization of right of use ground lease assets	453	0
Net change in other operating assets	(24,752)	(9,163)
Net change in other operating liabilities	44,421	37,110
Net cash provided by operating activities	301,390	317,215
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for development properties and undeveloped land	(554,951)	(311,347)
Expenditures for acquisition of undeveloped land (Note 2)	(40,027)	(311,299)
Expenditures for operating properties and other capital assets	(99,479)	(107,825)
Expenditures for acquisition of operating properties	0	(111,029)
Net proceeds received from dispositions (Note 3)	17,271	0
Net decrease in acquisition-related deposits (Note 4)	(49,998)
Net decrease in acquisition-related deposits (Note 4)		21,000
Proceeds received from repayment of note receivable	0	15,100
Net cash used in investing activities	(727,184)	(805,400)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of common units	353,904	130,744
Proceeds from the issuance of unsecured debt (Note 5)	499,390	50,000
Borrowings on unsecured revolving credit facility (Note 5)	630,000	645,000
Repayments on unsecured revolving credit facility (Note 5)	(675,000)	(285,000)
Borrowings on unsecured debt	0	120,000
Principal payments and repayments of secured debt (Note 5)	(75,844)	(2,670)
Financing costs	(5,548)	(2,278)
Repurchase of common units and restricted stock units	(14,269)	(16,553)
Proceeds from exercise of stock options	703	41
Distributions to noncontrolling interests in consolidated property partnerships	(10,844)	(7,014)
Contributions from noncontrolling interests in consolidated property partnerships	0	8,273
Distributions paid to common unitholders	(143,812)	(132,639)
Net cash provided by financing activities	558,680	507,904
Net increase in cash and cash equivalents and restricted cash	132,886	19,719
Cash and cash equivalents and restricted cash, beginning of period	171,034	66,798
Cash and cash equivalents and restricted cash, end of period	303,920	86,517
Kilroy Realty L.P. [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	137,307	111,036
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of real estate assets and leasing costs	199,967	186,242
Depreciation of non-real estate furniture, fixtures and equipment	3,650	3,179
(Recoveries of) provision for bad debts and write-offs (Note 1)	(3,685)	6,714
Non-cash amortization of share-based compensation awards	20,200	18,901
Non-cash amortization of deferred financing costs and debt discounts and premiums	911	816
Non-cash amortization of net below market rents	(6,241)	(7,647)
Gain on sale of depreciable operating properties (Note 3)	(7,169)	0
Non-cash amortization of deferred revenue related to tenant-funded tenant improvements	(14,947)	(13,680)
Straight-line rents	(48,725)	(16,293)
Amortization of right of use ground lease assets	453	0
Net change in other operating assets	(24,752)	(9,163)
Net change in other operating liabilities	44,421	37,110
Net cash provided by operating activities	301,390	317,215
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for development properties and undeveloped land	(554,951)	(311,347)
Expenditures for acquisition of undeveloped land (Note 2)	(40,027)	(311,299)
Expenditures for operating properties and other capital assets	(99,479)	(107,825)
Expenditures for acquisition of operating properties	0	(111,029)
Net proceeds received from dispositions (Note 3)	17,271	0
Net decrease in acquisition-related deposits (Note 4)	(49,998)
Net decrease in acquisition-related deposits (Note 4)		21,000
Proceeds received from repayment of note receivable	0	15,100
Net cash used in investing activities	(727,184)	(805,400)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of common units	353,904	130,744
Proceeds from the issuance of unsecured debt (Note 5)	499,390	50,000
Borrowings on unsecured revolving credit facility (Note 5)	630,000	645,000
Repayments on unsecured revolving credit facility (Note 5)	(675,000)	(285,000)
Borrowings on unsecured debt	0	120,000
Principal payments and repayments of secured debt (Note 5)	(75,844)	(2,670)
Financing costs	(5,548)	(2,278)
Repurchase of common units and restricted stock units	(14,269)	(16,553)
Proceeds from exercise of stock options	703	41
Distributions to noncontrolling interests in consolidated property partnerships	(10,844)	(7,014)
Contributions from noncontrolling interests in consolidated property partnerships	0	8,273
Distributions paid to common unitholders	(143,812)	(132,639)
Net cash provided by financing activities	558,680	507,904
Net increase in cash and cash equivalents and restricted cash	132,886	19,719
Cash and cash equivalents and restricted cash, beginning of period	171,034	66,798
Cash and cash equivalents and restricted cash, end of period	$ 303,920	$ 86,517

Organization, Ownership and Bas

Organization, Ownership and Basis of Presentation	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Ownership and Basis of Presentation	Organization, Ownership and Basis of Presentation Organization and Ownership 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 Greater Los Angeles, 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, 2019 : Number of Buildings Rentable Square Feet Number of Tenants Percentage Occupied Percentage Leased Stabilized Office Properties 93 13,322,212 438 92.1 % 97.3 % Number of Number of Units 2019 Average Occupancy Stabilized Residential Property 1 200 78.5 % Our stabilized portfolio includes all of our properties with the exception of development and redevelopment properties currently committed for construction, under construction, or in the tenant improvement phase, undeveloped land, recently completed residential properties not yet stabilized and real estate assets held for sale. 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 properties in the tenant improvement phase as office and retail properties that we are developing or redeveloping where the project has reached cold shell condition and is ready for tenant improvements, which may require additional major base building construction before being placed in service. Projects in the tenant improvement phase are added to our stabilized portfolio once the project reaches the earlier of 95% occupancy or one year from the date of the cessation of major base building construction activities. Costs capitalized to construction in progress for development and redevelopment properties are transferred to land and improvements, buildings and improvements, and deferred leasing costs on our consolidated balance sheets at the historical cost of the property as the projects are placed in service. During the nine months ended September 30, 2019 , we added one development project to our stabilized office portfolio consisting of 394,340 square feet in San Francisco, California. As of September 30, 2019 , the following properties were excluded from our stabilized portfolio. We did not have any redevelopment properties at September 30, 2019 . Number of Properties/Projects Estimated Rentable Square Feet (1) / Units Properties held for sale (2) 1 271,556 Completed residential development project (3) 1 237 units In-process development projects - tenant improvement (4) 2 846,000 In-process development projects - under construction (5) 6 2,295,000 ________________________ (1) Estimated rentable square feet upon completion. (2) See Note 3 “Dispositions and Real Estate Held for Sale” for additional information. (3) Represents our recently completed residential units that are not yet stabilized. (4) Includes 96,000 square feet of retail space. (5) In addition to the estimated office rentable square feet noted above, development projects under construction also include 564 residential units. Our stabilized portfolio also excludes our future development pipeline, which as of September 30, 2019 was comprised of four potential development sites, representing approximately 60 gross acres of undeveloped land. As of September 30, 2019 , 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 eight 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 and a development project held through two consolidated variable interest entities for future transactions intended to qualify as like-kind exchanges pursuant to Section 1031 of the Code (“Section 1031 Exchanges”). 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, 2019 , 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, 2019 , 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, 303 Second LLC, 100 First 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, 303 Second LLC, 100 First LLC, Redwood LLC and all of our wholly-owned and controlled subsidiaries. All intercompany balances and transactions have been eliminated in the consolidated financial statements. As of September 30, 2019 , the Company owned an approximate 98.1% common general partnership interest in the Operating Partnership. The remaining approximate 1.9% common limited partnership interest in the Operating Partnership as of September 30, 2019 was owned by non-affiliated investors and certain of our executive officers and directors. 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. 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, 2019 . 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, 2018 . Variable Interest Entities The Operating Partnership is a variable interest entity (“VIE”) that is consolidated by the Company as the primary beneficiary 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, 2019 , the consolidated financial statements of the Company included five VIEs in addition to the Operating Partnership: 100 First LLC, 303 Second LLC and three entities established during the third quarter of 2019 to facilitate potential future Section 1031 Exchanges. At September 30, 2019 , the Operating Partnership was determined to be the primary beneficiary of these five VIEs since the Operating Partnership had the ability to control the activities that most significantly impact each of the VIE’s economic performance. As of September 30, 2019 , the five VIEs’ total assets, liabilities and noncontrolling interests included on our consolidated balance sheet were approximately $552.4 million (of which $434.5 million related to real estate held for investment), approximately $36.3 million and approximately $187.6 million , respectively. Revenues, income and net assets generated by 100 First LLC and 303 Second LLC may only be used to settle their contractual obligations, which primarily consist of operating expenses, capital expenditures and required distributions. At December 31, 2018 , 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 2018 to facilitate a transaction intended to qualify as a like-kind exchange pursuant to Section 1031 of the Code (“Section 1031 Exchange”). In January 2019, the Section 1031 Exchange was successfully completed and the related VIE was terminated. At December 31, 2018 , the impact of consolidating the VIEs increased the Company’s total assets, liabilities and noncontrolling interests on our consolidated balance sheet by approximately $615.4 million (of which $543.9 million related to real estate held for investment), approximately $45.1 million and approximately $186.4 million , respectively. Accounting Pronouncements Adopted January 1, 2019 Effective January 1, 2019, we adopted Financial Accounting Standards Board (“FASB”) ASU No. 2016-02 “Leases (Topic 842)” (“Topic 842”) and the related FASB ASU Nos. 2018-01, 2018-10, 2018-11, 2018-20 and 2019-01 which provide practical expedients, technical corrections and improvements for certain aspects of ASU 2016-02, on a modified retrospective basis. Topic 842 establishes a single comprehensive model for entities to use in accounting for leases and supersedes the existing leasing guidance. We evaluated each of the Company’s contracts to determine if the contract is or contains a lease and concluded that Topic 842 is applicable to the Company as a lessor in its tenant lease agreements and as a lessee in its ground leases. Lessor Accounting As a lessor, the Company’s leases with tenants for its real estate assets generally provide for the lease of space, as well as common area maintenance and parking. Under Topic 842, the lease of space is considered a lease component while the common area maintenance billings and tenant parking are considered nonlease components, which fall under revenue recognition guidance in Topic 606. However, upon adopting the guidance in Topic 842, the Company determined that its tenant leases met the criteria to apply the practical expedient provided by ASU 2018-11 to recognize the lease and non-lease components together as one single component. This conclusion was based on the consideration that 1) the timing and pattern of transfer of the nonlease components and associated lease component are the same, and 2) the lease component, if accounted for separately, would be classified as an operating lease. As the lease of space is the predominant component of the Company’s leasing arrangements, we accounted for all lease and non-lease components as one single component under Topic 842. As a result, the adoption of Topic 842 did not have any impact on the Company’s timing or pattern of recognition of rental revenues as compared to previous guidance. Transient daily parking revenue will be accounted for under the guidance in Topic 606 and included in other property income in our consolidated statements of operations. To reflect their recognition as one lease component, rental revenues, tenant reimbursements and other lease related property income related to leases that also meet the requirements of the practical expedient provided by ASU 2018-11 have been combined in one line item subsequent to the adoption of Topic 842 for the three and nine months ended September 30, 2019 in rental income on the Company’s consolidated statements of operations. In addition, under Topic 842, lessor costs for certain services directly reimbursed by tenants, which were previously presented on a net basis under previous guidance, are required to be presented on a gross basis in revenues and expenses. During the three and nine months ended September 30, 2019 , we incurred additional property expenses of $4.1 million and $10.1 million , respectively, for which we were reimbursed, that were not required to be grossed up under the previous guidance. We presented this amount on a gross basis within rental income and property expenses in the Company’s consolidated statements of operations as a result of the adoption, which had no impact on net income. Our rental income is mostly comprised of fixed contractual payments defined under the lease that, in most cases, escalate annually over the term of the lease at fixed rates. Additionally, rental income includes variable payments for tenant reimbursements of property-related expenses and payments based on a percentage of tenant’s sales. The table below sets forth the allocation of rental income between fixed and variable payments for the three and nine months ended September 30, 2019 : Three Months Ended Nine Months Ended September 30, 2019 September 30, 2019 (in thousands) Fixed lease payments $ 181,851 $ 526,678 Variable lease payments 30,470 82,654 Total rental income $ 212,321 $ 609,332 Leasing Costs Upon adoption of Topic 842, the Company elected to apply the package of practical expedients provided and did not reassess the following as of January 1, 2019: 1) whether any expired or existing contracts are or contain leases; 2) the lease classification for any expired or existing leases; and 3) initial direct costs for any existing leases. Under Topic 842, initial direct costs for both lessees and lessors would include only those costs that are incremental to the arrangement and would not have been incurred if the lease had not been obtained. As a result, beginning January 1, 2019, the Company will no longer capitalize internal leasing costs and third-party legal leasing costs and instead will expense these costs as incurred. These expenses are included in leasing costs and general and administrative expenses on our consolidated statements of operations in 2019. During the three and nine months ended September 30, 2019 , the Company expensed approximately $2.4 million and $8.4 million , respectively, of indirect leasing costs which would have been capitalized prior to the adoption of Topic 842. The election of the package of practical expedients described above permits us to continue to account for our leases that commenced before January 1, 2019 under the previously existing lease accounting guidance for the remainder of their lease terms, and to apply the new lease accounting guidance to leases commencing or modified after January 1, 2019. On January 1, 2019, we recognized a $3.1 million cumulative-effect adjustment, primarily related to internal leasing costs and legal leasing costs for tenant leases that had not commenced prior to that date, to increase distributions in excess of earnings for the Company and partners’ capital for the Operating Partnership in connection with our adoption of Topic 842. Allowances for Tenant and Deferred Rent Receivables Upon the adoption of Topic 842 on January 1, 2019, our determination of the adequacy of the Company’s allowances for tenant receivables includes a binary assessment of whether or not the amounts due under a tenant’s lease agreement are probable of collection. For such amounts that are deemed probable of collection, revenue continues to be recorded on a straight-line basis over the lease term. For such amounts that are deemed not probable of collection, revenue is recorded as the lesser of (i) the amount which would be recognized on a straight-line basis or (ii) cash that has been received from the tenant, with any tenant and deferred rent receivable balances charged as a direct write-off against rental income in the period of the change in the collectability determination. In addition, for tenant and deferred rent receivables deemed probable of collection we also may record an allowance under other authoritative GAAP depending upon our evaluation of the individual receivables, specific credit enhancements, current economic conditions, and other relevant factors. Such allowances are recorded as increases or decreases through rental income on our consolidated statements of operations. Lessee Accounting The Company’s ground leases are the primary contracts in which we are the lessee. Upon adoption of Topic 842 on January 1, 2019, the Company had four existing ground leases which were classified as operating leases. We elected to apply the practical expedient to use hindsight in determining the lease term of our existing ground leases. As discussed above, the Company also elected to apply the package of practical expedients provided by Topic 842 and therefore did not reassess the classification of these ground leases. Existing ground leases that commenced before the January 1, 2019 adoption date continued to be accounted for as operating leases, and the new guidance did not have a material impact on our recognition of ground lease expense or our results of operations. However, for periods beginning after January 1, 2019, we are now required to recognize a lease liability on our consolidated balance sheets equal to the present value of the minimum future lease payments required in accordance with each ground lease, as well as a right of use asset equal to the lease liability adjusted for above and below market intangibles and deferred leasing costs. The adoption of Topic 842 resulted in the recognition of right of use ground lease assets totaling $82.9 million and ground lease liabilities totaling $87.4 million on January 1, 2019. There was no material impact to our consolidated statements of operations or consolidated statements of cash flows as a result of adoption of this new guidance. For further information, refer to Note 11. For leases with a term of 12 months or less where we are the lessee, we made an accounting policy election by class of underlying asset not to recognize right of use lease assets and lease liabilities. We recognize lease expense for such leases generally on a straight-line basis over the lease term. The following are our updated significant accounting policies that have been affected by the adoption of Topic 842. Significant Accounting Policies Revenue Recognition and Allowances for Tenant and Deferred Rent Receivables We recognize revenue from rent, tenant reimbursements, parking and other lease-related revenue once all of the following criteria are met: (i) the agreement has been fully executed and delivered, (ii) services have been rendered, (iii) the amount is fixed or determinable and (iv) payment has been received or the collectability of the amount due is probable. Lease termination fees are amortized over the remaining lease term, if applicable. If there is no remaining lease term, they are recognized when received and realized. Minimum annual rental revenues are recognized in rental revenues on a straight-line basis over the non-cancellable term of the related lease. We carry our current and deferred rent receivables net of allowances for amounts that may not be collected. Prior to the adoption of Topic 842 on January 1, 2019, the allowances are increased or decreased through provision for bad debts on our consolidated statements of operations. Upon the adoption of Topic 842 on January 1, 2019, our determination of the adequacy of the Company's allowances for tenant receivables includes a binary assessment of whether or not the amounts due under a tenant’s lease agreement are probable of collection. For such amounts that are deemed probable of collection, revenue continues to be recorded on a straight-line basis over the lease term. For such amounts that are deemed not probable of collection, revenue is recorded as the lesser of (i) the amount which would be recognized on a straight-line basis or (ii) cash that has been received from the tenant, with any tenant and deferred rent receivable balances charged as a direct write-off against rental income in the period of the change in the collectability determination. In addition, for tenant and deferred rent receivables deemed probable of collection we also may record an allowance under other authoritative GAAP depending upon our evaluation of the individual receivables, specific credit enhancements, current economic conditions, and other relevant factors. Such allowances are recorded as increases or decreases through rental income on our consolidated statements of operations. For the three months ended September 30, 2019 , we recorded a provision for bad debts of $0.1 million . For the nine months ended September 30, 2019 , we recorded a net reversal of allowance for tenant and deferred rent receivables of $3.2 million primarily due to the improved credit quality of a tenant that we previously recorded a provision against during the nine months ended September 30, 2018 . For the three and nine months ended September 30, 2018 , we recorded a provision for bad debts of $1.3 million and $6.7 million , respectively, primarily related to this tenant. Rental revenue recognition commences when the tenant takes possession or controls the physical use of the leased space. In order for the tenant to take possession, the leased space must be substantially complete and ready for its intended use. In order to determine whether the leased space is substantially complete and ready for its intended use, we begin by determining whether the Company or the tenant owns the tenant improvements. When we conclude that the Company is the owner of tenant improvements, rental revenue recognition begins when the tenant takes possession of the finished space, which is generally when Company-owned tenant improvements are substantially complete. In certain instances, when we conclude that the Company is not the owner (the tenant is the owner) of tenant improvements, rental revenue recognition begins when the tenant takes possession or controls the physical use of the leased space. When we conclude that the Company is the owner of tenant improvements, we record the cost to construct the tenant improvements, including costs paid for or reimbursed by the tenants, as a capital asset. For these tenant improvements, we record the amount funded by or reimbursed by the tenants as deferred revenue, which is amortized on a straight-line basis as additional rental income over the term of the related lease. When we conclude that the tenant is the owner of tenant improvements for accounting purposes, we record our contribution towards those improvements as a lease incentive, which is included in deferred leasing costs and acquisition-related intangible assets, net on our consolidated balance sheets and amortized as a reduction to rental income on a straight-line basis over the term of the related lease. For residential properties, we commence revenue recognition upon lease commencement. Residential rental revenue is recognized on a straight-line basis over the term of the related lease, net of any concessions. Tenant Reimbursements Reimbursements from tenants, consisting of amounts due from tenants for common area maintenance, real estate taxes and other recoverable costs, are recognized in rental income subsequent to the adoption of Topic 842 in the period the recoverable costs are incurred. Tenant reimbursements where we pay the associated costs directly to third-party vendors and are reimbursed by our tenants are recognized and recorded on a gross basis. Other Property Income Other property income primarily includes amounts recorded in connection with transient daily parking, tenant bankruptcy settlement payments, broken deal income and property damage settlement related payments. Other property income also includes miscellaneous income from tenants, restoration fees and fees for late rental payments. Amounts recorded within other property income fall within the scope of Topic 606 and are accounted for at the point in time when control of the goods or services transfers to the customer and our performance obligation is satisfied. Accounting Pronouncements Effective in 2020 and Beyond ASU No. 2016-13 “Financial Instruments - Credit Losses (Topic 326)” 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. In November 2018, the FASB released ASU No. 2018-19 “Codification Improvements to Topic 326, Financial Instrument - Credit Losses.” This ASU clarifies that receivables arising from operating leases are not within the scope of Subtopic 326-20 “Financial Instruments – Credit Losses.” Instead, impairment of receivables arising from operating leases should be accounted for under Subtopic 842-30 “Leases – Lessor.” 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 anticipate that the guidance will have a material impact on its consolidated financial statements or notes to its consolidated financial statements. ASU No. 2018-13 “Fair Value Measurement (Topic 820)” On August 28, 2018, the FASB issued ASU No. 2018-13 (“ASU 2018-13”) to amend the disclosure requirements for fair value measurements. The amendments in ASU 2018-13 include new, modified and eliminated disclosure requirements and are the result of a broader disclosure project called FASB Concepts Statement, Conceptual Framework for Financial Reporting - Chapter 8: Notes to Financial Statements (the “Concepts Statement”), which the FASB finalized on August 28, 2018. The FASB used the guidance in the Concepts Statement to improve the effectiveness of Topic 820’s disclosure requirements. ASU 2018-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted for any eliminated or modified disclosures. The Company does not anticipate that the guidance will have a material impact on its consolidated financial statements or notes to its consolidated financial statements. ASU No. 2018-15 “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40)” On August 29, 2018, the FASB issued ASU No. 2018-15 (“ASU 2018-15”) to amend a customer’s accounting for implementation costs incurred in a cloud computing arrangement that is a service contract. ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). ASU 2018-15 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted, including adoption in any interim period. ASU 2018-15 can be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. The Company does not anticipate that the guidance will have a material impact on its consolidated financial statements or notes to its consolidated financial statements.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2019
Asset Acquisitions [Abstract]
Acquisitions	Acquisitions Development Property Acquisitions During the nine months ended September 30, 2019 , we acquired the following development properties listed below from an unrelated third party. The acquisition was funded with proceeds from the Company’s unsecured revolving credit facility. Property Date of Acquisition Submarket Type Purchase Price (in millions) (1) 1335 Broadway & 901 Park Boulevard, San Diego, CA August 19, 2019 East Village Land $ 40.0 ________________________ (1)

Dispositions and Real Estate He

Dispositions and Real Estate Held for Sale	9 Months Ended
	Sep. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Dispositions and Real Estate Held for Sale	Dispositions and Real Estate Held for Sale Operating Property Dispositions The following table summarizes the operating property sold during the nine months ended September 30, 2019 : Property Month of Disposition Number of Buildings Rentable Square Feet Sales Price (in millions) (1) 2829 Townsgate Road, Thousand Oaks, CA May 1 84,098 $ 18.3 __________________ (1) Represents gross sales price before the impact of broker commissions and closing costs. The total gain on the sale of the operating property sold during the nine months ended September 30, 2019 was $7.2 million . Real Estate Assets Held for Sale As of September 30, 2019 , the following property was classified as held for sale: Property Submarket Property Type Number of Buildings Rentable Square Feet 2211 Michelson Drive, Irvine, CA Orange County Office 1 271,556 The major classes of assets and liabilities of the property held for sale as of September 30, 2019 were as follows: Real estate assets and other assets held for sale (in thousands) Land and improvements $ 9,319 Buildings and improvements 90,147 Total real estate held for sale 99,466 Accumulated depreciation and amortization (29,420 ) Total real estate held for sale, net 70,046 Current receivables, net 79 Deferred rent receivables, net 1,288 Deferred leasing costs and acquisition-related intangibles, net 1,733 Prepaid expenses and other assets, net 4,605 Total real estate held for sale, net $ 77,751 Liabilities and deferred revenue of real estate assets held for sale Accounts payable and accrued expenses and other $ 3,658 Deferred revenue and acquisition-related intangible liabilities, net 122 Rents received in advance and tenant security deposits 1,131 Liabilities and deferred revenue of real estate assets held for sale $ 4,911

Prepaid Expenses and Other Asse

Prepaid Expenses and Other Assets, Net	9 Months Ended
	Sep. 30, 2019
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, 2019 and December 31, 2018 : September 30, 2019 December 31, 2018 (in thousands) Furniture, fixtures and other long-lived assets, net (1) $ 36,192 $ 36,833 Notes receivable, net (2) 1,598 2,113 Prepaid expenses & acquisition deposits (1)(3) 71,917 13,927 Total prepaid expenses and other assets, net $ 109,707 $ 52,873 ________________________ (1) Excludes amounts related to properties held for sale as of September 30, 2019 . (2) Notes receivable are shown net of a valuation allowance of approximately $3.6 million and $2.9 million as of September 30, 2019 and December 31, 2018 , respectively. (3) Includes $50.0 million

Secured and Unsecured Debt of t

Secured and Unsecured Debt of the Operating Partnership	9 Months Ended
	Sep. 30, 2019
Kilroy Realty L.P. [Member]
Debt Instrument [Line Items]
Secured and Unsecured Debt of the Operating Partnership	Secured and Unsecured Debt of the Operating Partnership Secured Debt On February 11, 2019, the Company repaid at par a secured mortgage note payable for $74.3 million that was due in June 2019. Unsecured Debt The Company generally guarantees all of the Operating Partnership’s unsecured debt obligations including the unsecured revolving credit facility, the unsecured term loan facility and all of the unsecured senior notes. Unsecured Senior Notes In September 2019, the Operating Partnership issued $500.0 million of aggregate principal amount of unsecured senior notes in a registered public offering. The outstanding balance of the unsecured senior notes is included in unsecured debt, net of an initial issuance discount of $0.6 million , on our consolidated balance sheets. The unsecured senior notes, which are scheduled to mature on February 15, 2030 , require semi-annual interest payments each February and August based on a stated annual interest rate of 3.050% . The Operating Partnership may redeem the notes at any time prior to February 15, 2030 , either in whole or in part, subject to the payment of an early redemption premium prior to a par call option period commencing three months prior to maturity. Unsecured Revolving Credit Facility and Term Loan Facility The following table summarizes the balance and terms of our unsecured revolving credit facility as of September 30, 2019 and December 31, 2018 : September 30, 2019 December 31, 2018 (in thousands) Outstanding borrowings $ — $ 45,000 Remaining borrowing capacity 750,000 705,000 Total borrowing capacity (1) $ 750,000 $ 750,000 Interest rate (2) 3.02 % 3.48 % Facility fee-annual rate (3) 0.200% Maturity date July 2022 ________________________ (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 the contractual rate of LIBOR plus 1.000% as of September 30, 2019 and December 31, 2018 . (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, 2019 and December 31, 2018 , $3.7 million and $4.7 million of unamortized deferred financing costs, respectively, which are included in prepaid expenses and other assets, net on our consolidated balance sheets, remained to be amortized through the maturity date of our unsecured revolving credit facility. 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, 2019 and December 31, 2018 : September 30, 2019 December 31, 2018 (in thousands) Outstanding borrowings $ 150,000 $ 150,000 Remaining borrowing capacity — — Total borrowing capacity (1) $ 150,000 $ 150,000 Interest rate (2) 3.13 % 3.49 % Undrawn facility fee-annual rate (3) 0.200% Maturity date July 2022 ________________________ (1) As of September 30, 2019 and December 31, 2018 , $0.7 million and $0.9 million of unamortized deferred financing costs, respectively, remained to be amortized through the maturity date of our unsecured term loan facility. (2) Our unsecured term loan facility interest rate was calculated based on the contractual rate of LIBOR plus 1.100% as of September 30, 2019 and December 31, 2018 . (3) Prior to borrowing the full capacity of our unsecured term loan facility, the undrawn facility fee was calculated based on any unused borrowing capacity and was paid on a quarterly basis. Debt Covenants and Restrictions The unsecured revolving credit facility, the unsecured term loan facility, the unsecured senior notes, the Series A and B Notes due 2026 and Series A and B Notes due 2027 and 2029 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, 2019 . Debt Maturities The following table summarizes the stated debt maturities and scheduled amortization payments of our issued and outstanding debt as of September 30, 2019 : Year (in thousands) Remaining 2019 $ 465 2020 5,137 2021 5,342 2022 155,554 2023 305,775 2024 431,006 Thereafter 2,431,688 Total aggregate principal value (1) $ 3,334,967 ________________________ (1) Includes gross principal balance of outstanding debt before the effect of the following at September 30, 2019 : $21.1 million of unamortized deferred financing costs for the unsecured term loan facility, unsecured senior notes and secured debt and $6.7 million of unamortized discounts for the unsecured senior notes. 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, 2019 and 2018 . 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, 2019 2018 2019 2018 (in thousands) Gross interest expense $ 32,220 $ 30,231 $ 95,507 $ 85,834 Capitalized interest and deferred financing costs (20,585 ) (19,156 ) (60,902 ) (48,549 ) Interest expense $ 11,635 $ 11,075 $ 34,605 $ 37,285

Stockholders' Equity of the Com

Stockholders' Equity of the Company	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Stockholders' Equity of the Company	Stockholders’ Equity of the Company At-The-Market Stock Offering Program Under our at-the-market stock offering program, which commenced in June 2018, we may offer and sell shares of our common stock having an aggregate gross sales price up to $500.0 million from time to time in “at-the-market” offerings. In connection with the at-the-market program, the Company may enter into forward equity sale agreements with certain financial institutions acting as forward purchasers whereby, at our discretion, the forward purchasers may borrow and sell shares of our common stock under our at-the-market program. The use of a forward equity sale agreement allows the Company to lock in a share price on the sale of shares of our common stock at the time the agreement is executed but defer settling the forward equity sale agreements and receiving the proceeds from the sale of shares until a later date. During the nine months ended September 30, 2019 , we executed 12-month forward equity sale agreements with financial institutions acting as forward purchasers under our at-the-market stock offering program to sell 1,201,204 shares of common stock at a weighted average sales price of $75.92 per share before underwriting discounts, commissions and offering expenses. The Company did not receive any proceeds from the sale of its common shares by the forward purchasers. The Company currently expects to fully physically settle the forward equity sale agreements and receive cash proceeds upon one or more settlement dates, at the Company’s discretion, prior to the final settlement dates under the forward equity sale agreements in March and April 2020, in which case we expect to receive aggregate net cash proceeds at settlement equal to the number of shares specified in such forward equity sale agreement multiplied by the relevant forward price per share. The weighted average forward sale price that we expect to receive upon physical settlement of the agreements will be subject to adjustment for (i) a floating interest rate factor equal to a specified daily rate less a spread, (ii) the forward purchasers’ stock borrowing costs and (iii) scheduled dividends during the term of the agreements. We have not settled any portion of these forward equity sale agreements as of the date of this filing. Upon physical settlement, the Company will contribute the net proceeds from the issuance of shares of our common stock to the Operating Partnership in exchange for an equal number of units in the Operating Partnership. Since commencement of the program, we have completed sales of 447,466 shares of common stock through September 30, 2019 and 1,201,204 shares have been sold by forward purchasers under forward equity sale agreements, which have not been settled as of the date of this filing. We did not settle any forward sales of common stock under our at-the-market program during the nine months ended September 30, 2019 and as of September 30, 2019 approximately $375.0 million remains 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. 2018 Common Stock Forward Equity Sale Agreements In July 2019, the Company physically settled the forward equity sale agreements entered into in August 2018 with certain financial institutions acting as forward purchasers in connection with an offering of 5,000,000 shares of common stock at an initial gross offering price of $360.5 million , or $72.10 per share, before underwriting discounts, commissions and offering expenses. Upon settlement, the Company issued 5,000,000 shares of common stock for net proceeds of $354.3 million

Noncontrolling Interests on the

Noncontrolling Interests on the Company's Consolidated Financial Statements	9 Months Ended
	Sep. 30, 2019
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 98.1% , 98.0% , and 98.0% common general partnership interest in the Operating Partnership as of September 30, 2019 , December 31, 2018 and September 30, 2018 , respectively. The remaining approximate 1.9% , 2.0% , and 2.0% common limited partnership interest as of September 30, 2019 , December 31, 2018 and September 30, 2018 , respectively, was owned by non-affiliated investors and certain of our executive officers and directors in the form of noncontrolling common units. There were 2,023,287 , 2,025,287 and 2,025,287 common units outstanding held by these investors, executive officers and directors as of September 30, 2019 , December 31, 2018 and September 30, 2018 , 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 $158.0 million and $126.4 million as of September 30, 2019 and December 31, 2018

Partners' Capital of the Operat

Partners' Capital of the Operating Partnership	9 Months Ended
	Sep. 30, 2019
Partners' Capital Notes [Abstract]
Partners’ Capital of the Operating Partnership	Partners’ Capital of the Operating Partnership Common Units Outstanding The following table sets forth the number of common units held by the Company and the number of common units held by non-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, 2019 December 31, 2018 September 30, 2018 Company owned common units in the Operating Partnership 106,011,916 100,746,988 100,746,988 Company owned general partnership interest 98.1 % 98.0 % 98.0 % Noncontrolling common units of the Operating Partnership 2,023,287 2,025,287 2,025,287 Ownership interest of noncontrolling interest 1.9 % 2.0 % 2.0 % For further discussion of the noncontrolling common units as of September 30, 2019 and December 31, 2018 , refer to Note 7.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation Stockholder Approved Equity Compensation Plans As of September 30, 2019 , we maintained one share-based incentive compensation plan, the Kilroy Realty 2006 Incentive Award Plan, as amended (the “2006 Plan”). The Company has a currently effective registration statement registering 9.2 million shares of our common stock for possible issuance under the 2006 Plan. As of September 30, 2019 , approximately 0.4 million 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 maximum levels for the performance and market conditions (as defined below) for awards still in a performance period. 2019 Share-Based Compensation Grants In February 2019 , the Executive Compensation Committee of the Company’s Board of Directors awarded 288,378 restricted stock units (“RSUs”) to certain officers of the Company under the 2006 Plan, which included 143,396 RSUs (at the target level of performance) that are subject to market and/or performance-based vesting requirements (the “2019 Performance-Based RSUs”) and 144,982 RSUs that are subject to time-based vesting requirements (the “2019 Time-Based RSUs”). During the three months ended September 30, 2019 , 10,733 2019 Time-Based RSUs, 16,235 2019 Performance-Based RSUs and 98,569 time vest and performance RSUs that were granted in prior years were forfeited. 2019 Performance-Based RSU Grant The 2019 Performance-Based RSUs are scheduled to vest at the end of a three year period (consisting of calendar years 2019-2021). A target number of 2019 Performance-Based RSUs were awarded, and the final number of 2019 Performance-Based RSUs that vest (which may be more or less than the target number) will be based upon (1) the achievement of pre-set FFO per share goals for the year ending December 31, 2019 that applies to 100% of the Performance-Based RSUs awarded (the “FFO performance condition”) and (2) a performance measure that applies to 50% of the award based upon a measure of the Company’s average debt to EBITDA ratio for the three year performance period (the “debt to EBITDA ratio performance condition”) and a market measure that applies to the other 50% of the award based upon the relative ranking of the Company’s total stockholder return for the three year performance period compared to the total stockholder returns of an established comparison group of companies over the same period (the “market condition”). The 2019 Performance-Based RSUs are also subject to a three year service vesting provision (the “service vesting condition”) and are scheduled to cliff vest on the date the final vesting percentage is determined following the end of the three year performance period under the awards. The number of 2019 Performance-Based RSUs ultimately earned could fluctuate from the target number of 2019 Performance-Based RSUs granted based upon the levels of achievement for the FFO performance condition, the debt to EBITDA ratio performance condition, the market condition, and the extent to which the service vesting condition is satisfied. The estimate of the number of 2019 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, 2019 , the number of 2019 Performance-Based RSUs estimated to be earned based on the Company’s estimate of the performance conditions measured against the applicable goals was 207,138 , and the compensation cost recorded to date for this program was based on that estimate. Compensation expense for the 2019 Performance-Based RSU grant is recognized on a straight-line basis over the requisite service period for each participant, which is generally the three year service period. Each 2019 Performance-Based RSU represents the right, subject to the applicable vesting conditions, to receive one share of our common stock in the future. The determination of the grant date fair value of the portion of the 2019 Performance-Based RSU grants covered by the debt to EBITDA ratio performance condition was based on the $69.89 share price on the February 1, 2019 grant date. The determination of the grant date fair value of the portion of the 2019 Performance-Based RSU grants covered by the market condition was calculated using a Monte Carlo simulation pricing model based on the assumptions in the table below, which resulted in a $72.57 grant date fair value per share. Fair Value Assumptions Valuation date February 1, 2019 Expected share price volatility 19.0% Risk-free interest rate 2.48% Fair value per share on valuation date 72.57 The computation of expected volatility is based on a blend of the historical volatility of our shares of common stock over approximately 5.8 years, as that is expected to be most consistent with future volatility and equates to a time period twice as long as the approximate 2.9 -year 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 1, 2019 . The total grant date fair value of the 2019 Performance-Based RSU awards was $10.2 million on the February 1, 2019 grant date of the awards. For the three months ended September 30, 2019 , we recorded compensation expense based upon the grant date fair value per share for each component multiplied by the estimated number of RSUs to be earned as discussed above. 2019 Time-Based RSU Grant The 2019 Time-Based RSUs are scheduled to vest in three equal annual installments beginning on January 5, 2020 through January 5, 2022. Compensation expense for the 2019 Time-Based RSUs is recognized on a straight-line basis over the requisite service period for each participant, which is generally the three year service vesting period. Each 2019 Time-Based RSU represents the right to receive one share of our common stock in the future. The total grant date fair value of the 2019 Time-Based RSU awards was $10.1 million , which was based on the $69.89 closing share price of the Company’s common stock on the NYSE on the February 1, 2019 grant date of the awards. Share-Based Compensation Cost Recorded During the Period The total compensation cost for all share-based compensation programs was $6.8 million and $8.1 million for the three months ended September 30, 2019 and 2018 , respectively, and $24.4 million and $24.7 million for the nine months ended September 30, 2019 and 2018 , respectively. Of the total share-based compensation costs, $0.7 million and $4.2 million was capitalized as part of real estate assets for the three and nine months ended September 30, 2019 , and $1.5 million and $5.8 million was capitalized as part of real estate assets and deferred leasing costs for the three and nine months ended September 30, 2018 . As of September 30, 2019 , there was approximately $57.4 million of total unrecognized compensation cost related to nonvested incentive awards granted under share-based compensation arrangements that is expected to be recognized over a weighted-average period of 2.4 years. The remaining compensation cost related to these nonvested incentive awards had been recognized in periods prior to September 30, 2019 .

Future Minimum Rent

Future Minimum Rent	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Future Minimum Rent	Future Minimum Rent We have operating leases with tenants that expire at various dates through 2043 that are generally subject to scheduled fixed increases with certain leases containing adjustments in rent based on the Consumer Price Index. Generally, the leases grant tenants renewal options. Leases also provide for additional rents based on certain operating expenses. Future contractual minimum rent under operating leases as of September 30, 2019 (under Topic 842) for future periods is summarized as follows: Year Ending (in thousands) Remaining 2019 $ 145,027 2020 665,314 2021 703,649 2022 735,969 2023 717,898 2024 681,026 Thereafter 3,607,437 Total (1) $ 7,256,320 ______________ (1) Excludes residential leases and leases with a term of one year or less. Future contractual minimum rent under operating leases as of December 31, 2018 for future periods is summarized as follows: Year Ending (in thousands) 2019 $ 566,783 2020 632,875 2021 631,835 2022 620,684 2023 586,371 Thereafter 3,240,143 Total (1) $ 6,278,691 ______________ (1) Excludes residential leases and leases with a term of one year or less.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies General As of September 30, 2019 , we had commitments of approximately $1.2 billion , excluding our ground lease commitments, for contracts and executed leases directly related to our development projects and operating properties. Ground Leases The following table summarizes our properties that are held subject to long-term noncancellable ground lease obligations and the respective contractual expiration dates: Property Contractual Expiration Date (1) 601 108th Ave NE, Bellevue, WA November 2093 701, 801 and 837 N. 34th Street, Seattle, WA (2) December 2041 1701 Page Mill Road and 3150 Porter Drive, Palo Alto, CA December 2067 Kilroy Airport Center Phases I, II, and III, Long Beach, CA July 2084 ____________________ (1) Reflects the contractual expiration date prior to the impact of any extension or purchase options held by the Company. (2) The Company has three 10 -year and one 45 -year extension options for this ground lease, which if exercised would extend the expiration date to December 2116. These extensions options are not assumed to be exercised in our calculation of the present value of the future minimum lease payments for this lease. On January 1, 2019, we adopted Topic 842 and recognized ground lease liabilities on our consolidated balance sheets equal to the present value of the minimum lease payments required in accordance with each ground lease. We also recognized right of use ground lease assets equal to the ground lease liabilities adjusted for above and below market ground lease intangibles and deferred leasing costs. To determine the discount rates used to calculate the present value of the lease payments, we used a hypothetical curve derived from unsecured corporate borrowing rates over the lease terms. The weighted average discount rate for our ground leases was 5.15% . On January 1, 2019, we recognized right of use ground lease assets totaling $82.9 million and ground lease liabilities totaling $87.4 million . As of September 30, 2019 , the weighted average remaining lease term of our ground leases is 51 years. For the three and nine months ended September 30, 2019 , variable lease costs totaling $0.7 million and $2.3 million , respectively, were recorded to ground leases expense on our consolidated statements of operations. The minimum commitment under our ground leases as of September 30, 2019 (under Topic 842) for future periods is summarized as follows: Year Ending (in thousands) Remaining 2019 $ 1,301 2020 5,205 2021 5,205 2022 5,205 2023 5,205 2024 5,205 Thereafter 229,339 Total undiscounted cash flows (1)(2)(3)(4)(5) 256,665 Present value discount (169,048 ) Ground lease liabilities $ 87,617 ________________________ (1) Excludes contingent future rent payments based on gross income or adjusted gross income and reflects the minimum ground lease obligations before the impact of ground lease extension options. (2) One of our ground lease obligations is subject to a fair market value adjustment every five years ; however, the lease includes ground rent subprotection and infrastructure rent credits which currently limit our annual rental obligations to $1.0 million . The contractual obligations for that ground lease included above assumes the lesser of $1.0 million or annual lease rental obligation in effect as of September 30, 2019 . (3) One of our ground lease obligations includes a component which is based on the percentage of gross income that exceeds the minimum ground rent. The minimum rent is subject to increases every five years based on 50% of the average annual percentage rent for the previous five years. The contractual obligations for that lease included above assume the current annual ground lease obligation in effect at September 30, 2019 for the remainder of the lease term since we cannot predict future adjustments. (4) One of our ground lease obligations is subject to a fair market value adjustment every five years based on a combination of CPI adjustments and third-party appraisals limited to maximum increases annually. The contractual obligations for that lease included above assume the current annual ground lease obligation in effect at September 30, 2019 for the remainder of the lease term since we cannot predict future adjustments. (5) One of our ground lease obligations includes a component which is based on the percentage of adjusted gross income that exceeds the minimum ground rent. The minimum rent is subject to increases every ten years by an amount equal to 60% of the average annual percentage rent for the previous three years. The contractual obligations for this lease included above assume the current annual ground lease obligation in effect at September 30, 2019 for the remainder of the lease term since we cannot predict future adjustments. The minimum commitment under our ground leases as of December 31, 2018 for future periods is summarized as follows: Year Ending (in thousands) 2019 $ 5,154 2020 5,154 2021 5,154 2022 5,154 2023 5,154 Thereafter 233,619 Total (1)(2)(3)(4)(5) $ 259,389 ________________________ (1) Excludes contingent future rent payments based on gross income or adjusted gross income and reflects the minimum ground lease obligations before the impact of ground lease extension options. (2) One of our ground lease obligations is subject to a fair market value adjustment every five years ; however, the lease includes ground rent subprotection and infrastructure rent credits which currently limit our annual rental obligations to $1.0 million . The contractual obligations for that ground lease included above assumes the lesser of $1.0 million or annual lease rental obligation in effect as of December 31, 2018. (3) One of our ground lease obligations includes a component which is based on the percentage of gross income that exceeds the minimum ground rent. The minimum rent is subject to increases every five years based on 50% of the average annual percentage rent for the previous five years. The contractual obligations for that lease included above assume the current annual ground lease obligation in effect at December 31, 2018 for the remainder of the lease term since we cannot predict future adjustments. (4) One of our ground lease obligations is subject to a fair market value adjustment every five years based on a combination of CPI adjustments and third-party appraisals limited to maximum increases annually. The contractual obligations for that lease included above assume the current annual ground lease obligation in effect at December 31, 2018 for the remainder of the lease term since we cannot predict future adjustments. (5) One of our ground lease obligations includes a component which is based on the percentage of adjusted gross income that exceeds the minimum ground rent. The minimum rent is subject to increases every ten years by an amount equal to 60% of the average annual percentage rent for the previous three years. The contractual obligations for this lease included above assume the current annual ground lease obligation in effect at December 31, 2018 for the remainder of the lease term since we cannot predict future adjustments. Environmental Matters We follow the policy of monitoring all of our properties, including acquisition, development 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, 2019 , we had accrued environmental remediation liabilities of approximately $75.1 million recorded on our consolidated balance sheets in connection with certain of our in-process and future development projects. The accrued environmental remediation liabilities represent the remaining costs we estimate we will incur prior to and during the development process at various development acquisition sites. These estimates, which we developed with the assistance of third party experts, consist primarily of the removal of contaminated soil, performing environmental closure activities, constructing remedial systems and other related costs since we are required to dispose of any existing contaminated soil and sometimes perform other environmental closure or remedial activities when we develop new buildings at these sites. We record estimated environmental remediation obligations for acquired properties at the acquisition date when we are aware of such costs and when such costs are probable of being incurred and can be reasonably estimated. Estimated costs related to development environmental remediation liabilities are recorded as an increase to the cost of the development project. Actual costs are recorded as a decrease to the liability when incurred. These accruals are adjusted as an increase or decrease to the development project costs and as an increase or decrease to the accrued environmental remediation liability if we obtain further information or circumstances change. The environmental remediation obligations recorded at September 30, 2019 were not discounted to their present values since the amount and timing of cash payments are not fixed. It is possible that we could incur additional environmental remediation costs in connection with these development projects. However, potential additional environmental costs for these development projects cannot be reasonably estimated 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, 2019
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, 2019 and December 31, 2018 : Fair Value (Level 1) (1) September 30, 2019 December 31, 2018 Description (in thousands) Marketable securities (2) $ 26,188 $ 21,779 ________________________ (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 gain/loss 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 (loss) on marketable securities recorded during the three and nine months ended September 30, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Description (in thousands) (in thousands) Net gain on marketable securities $ 673 $ 271 $ 2,898 $ 289 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, 2019 and December 31, 2018 : September 30, 2019 December 31, 2018 Carrying Fair (1) Carrying Fair (1) (in thousands) Liabilities Secured debt, net $ 259,027 $ 271,224 $ 335,531 $ 335,885 Unsecured debt, net $ 3,048,209 $ 3,245,743 $ 2,552,070 $ 2,546,386 Unsecured line of credit $ — $ — $ 45,000 $ 45,058 ________________________ (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, 2019
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, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands, except share and per share amounts) Numerator: Net income attributable to Kilroy Realty Corporation $ 43,846 $ 34,400 $ 122,943 $ 98,195 Allocation to participating securities (1) (530 ) (507 ) (1,582 ) (1,492 ) Numerator for basic and diluted net income available to common stockholders $ 43,316 $ 33,893 $ 121,361 $ 96,703 Denominator: Basic weighted average vested shares outstanding 104,841,176 100,676,778 102,252,739 99,711,312 Effect of dilutive securities 518,728 551,556 619,697 497,333 Diluted weighted average vested shares and common share equivalents outstanding 105,359,904 101,228,334 102,872,436 100,208,645 Basic earnings per share: Net income available to common stockholders per share $ 0.41 $ 0.34 $ 1.19 $ 0.97 Diluted earnings per share: Net income available to common stockholders per share $ 0.41 $ 0.33 $ 1.18 $ 0.97 ________________________ (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, shares issuable under forward equity sale agreements and other securities are considered in our diluted earnings per share calculation for the three and nine months ended September 30, 2019 and 2018 . Certain market measure-based RSUs are not included in dilutive securities for the three and nine months ended September 30, 2019 and 2018 , 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 Commo_2

Net Income Available to Common Unitholders Per Unit of the Operating Partnership	9 Months Ended
	Sep. 30, 2019
Net Income Available To Common Unitholders [Line Items]
Net Income Available to Common Unitholders Per Unit of the Operating Partnership	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, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands, except share and per share amounts) Numerator: Net income attributable to Kilroy Realty Corporation $ 43,846 $ 34,400 $ 122,943 $ 98,195 Allocation to participating securities (1) (530 ) (507 ) (1,582 ) (1,492 ) Numerator for basic and diluted net income available to common stockholders $ 43,316 $ 33,893 $ 121,361 $ 96,703 Denominator: Basic weighted average vested shares outstanding 104,841,176 100,676,778 102,252,739 99,711,312 Effect of dilutive securities 518,728 551,556 619,697 497,333 Diluted weighted average vested shares and common share equivalents outstanding 105,359,904 101,228,334 102,872,436 100,208,645 Basic earnings per share: Net income available to common stockholders per share $ 0.41 $ 0.34 $ 1.19 $ 0.97 Diluted earnings per share: Net income available to common stockholders per share $ 0.41 $ 0.33 $ 1.18 $ 0.97 ________________________ (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, shares issuable under forward equity sale agreements and other securities are considered in our diluted earnings per share calculation for the three and nine months ended September 30, 2019 and 2018 . Certain market measure-based RSUs are not included in dilutive securities for the three and nine months ended September 30, 2019 and 2018 , 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.
Kilroy Realty L.P. [Member]
Net Income Available To Common Unitholders [Line Items]
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, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands, except unit and per unit amounts) Numerator: Net income attributable to Kilroy Realty, L.P. $ 44,589 $ 34,993 $ 124,998 $ 99,901 Allocation to participating securities (1) (530 ) (507 ) (1,582 ) (1,492 ) Numerator for basic and diluted net income available to common unitholders $ 44,059 $ 34,486 $ 123,416 $ 98,409 Denominator: Basic weighted average vested units outstanding 106,864,463 102,721,806 104,276,187 101,773,540 Effect of dilutive securities 518,728 551,556 619,697 497,333 Diluted weighted average vested units and common unit equivalents outstanding 107,383,191 103,273,362 104,895,884 102,270,873 Basic earnings per unit: Net income available to common unitholders per unit $ 0.41 $ 0.34 $ 1.18 $ 0.97 Diluted earnings per unit: Net income available to common unitholders per unit $ 0.41 $ 0.33 $ 1.18 $ 0.96 ________________________ (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, shares issuable under forward equity sale agreements and other securities are considered in our diluted earnings per share calculation for the three and nine months ended September 30, 2019 and 2018 . Certain market measure-based RSUs are not included in dilutive securities for the three and nine months ended September 30, 2019 and 2018 , 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, 2019
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, 2019 2018 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $58,337 and $46,761 as of September 30, 2019 and 2018, respectively $ 28,139 $ 32,175 Cash paid for amounts included in the measurement of ground lease liabilities $ 3,917 $ 3,598 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 148,468 $ 142,133 Assumption of accrued liabilities in connection with acquisitions $ 3,967 $ 40,624 Tenant improvements funded directly by tenants $ 10,254 $ 7,211 Initial measurement of operating right of use ground lease assets $ 82,938 $ — Initial measurement of operating ground lease liabilities $ 87,409 $ — NON-CASH FINANCING TRANSACTIONS: Accrual of dividends and distributions payable to common stockholders and common unitholders $ 53,205 $ 47,411 Exchange of common units of the Operating Partnership into shares of the Company’s common stock $ 78 $ 1,962 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, 2019 and 2018 . Nine Months Ended September 30, 2019 2018 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 51,604 $ 57,649 Restricted cash at beginning of period 119,430 9,149 Cash and cash equivalents and restricted cash at beginning of period $ 171,034 $ 66,798 Cash and cash equivalents at end of period $ 297,620 $ 86,517 Restricted cash at end of period 6,300 — Cash and cash equivalents and restricted cash at end of period $ 303,920 $ 86,517

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information of the Operating Partnership	9 Months Ended
	Sep. 30, 2019
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, 2019 2018 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $58,337 and $46,761 as of September 30, 2019 and 2018, respectively $ 28,139 $ 32,175 Cash paid for amounts included in the measurement of ground lease liabilities $ 3,917 $ 3,598 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 148,468 $ 142,133 Assumption of accrued liabilities in connection with acquisitions $ 3,967 $ 40,624 Tenant improvements funded directly by tenants $ 10,254 $ 7,211 Initial measurement of operating right of use ground lease assets $ 82,938 $ — Initial measurement of operating ground lease liabilities $ 87,409 $ — NON-CASH FINANCING TRANSACTIONS: Accrual of dividends and distributions payable to common stockholders and common unitholders $ 53,205 $ 47,411 Exchange of common units of the Operating Partnership into shares of the Company’s common stock $ 78 $ 1,962 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, 2019 and 2018 . Nine Months Ended September 30, 2019 2018 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 51,604 $ 57,649 Restricted cash at beginning of period 119,430 9,149 Cash and cash equivalents and restricted cash at beginning of period $ 171,034 $ 66,798 Cash and cash equivalents at end of period $ 297,620 $ 86,517 Restricted cash at end of period 6,300 — Cash and cash equivalents and restricted cash at end of period $ 303,920 $ 86,517
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, 2019 2018 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $58,337 and $46,761 as of September 30, 2019 and 2018, respectively $ 28,139 $ 32,175 Cash paid for amounts included in the measurement of ground lease liabilities $ 3,917 $ 3,598 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 148,468 $ 142,133 Assumption of accrued liabilities in connection with acquisitions $ 3,967 $ 40,624 Tenant improvements funded directly by tenants $ 10,254 $ 7,211 Initial measurement of operating right of use ground lease assets $ 82,938 $ — Initial measurement of operating ground lease liabilities $ 87,409 $ — NON-CASH FINANCING TRANSACTIONS: Accrual of distributions payable to common unitholders $ 53,205 $ 47,411 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, 2019 and 2018 . Nine Months Ended September 30, 2019 2018 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 51,604 $ 57,649 Restricted cash at beginning of period 119,430 9,149 Cash and cash equivalents and restricted cash at beginning of period $ 171,034 $ 66,798 Cash and cash equivalents at end of period $ 297,620 $ 86,517 Restricted cash at end of period 6,300 — Cash and cash equivalents and restricted cash at end of period $ 303,920 $ 86,517

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On October 15, 2019 , the Company completed the acquisition of a 100% leased, 158,000 square foot creative office campus for $186.0 million . The campus includes 19 buildings situated across 6.9 acres, located at 3101-3243 La Cienega Boulevard in the Culver City submarket of Los Angeles. On October 16, 2019 , aggregate dividends, distributions and dividend equivalents of $53.2 million were paid to common stockholders, common unitholders and RSU holders of record on September 30, 2019 .

Organization, Ownership and B_2

Organization, Ownership and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2019
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, 303 Second LLC, 100 First 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, 303 Second LLC, 100 First LLC, Redwood LLC and all of our wholly-owned and controlled subsidiaries. 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, 2019 . 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, 2018 .
New accounting pronouncements	Accounting Pronouncements Adopted January 1, 2019 Effective January 1, 2019, we adopted Financial Accounting Standards Board (“FASB”) ASU No. 2016-02 “Leases (Topic 842)” (“Topic 842”) and the related FASB ASU Nos. 2018-01, 2018-10, 2018-11, 2018-20 and 2019-01 which provide practical expedients, technical corrections and improvements for certain aspects of ASU 2016-02, on a modified retrospective basis. Topic 842 establishes a single comprehensive model for entities to use in accounting for leases and supersedes the existing leasing guidance. We evaluated each of the Company’s contracts to determine if the contract is or contains a lease and concluded that Topic 842 is applicable to the Company as a lessor in its tenant lease agreements and as a lessee in its ground leases. Lessor Accounting As a lessor, the Company’s leases with tenants for its real estate assets generally provide for the lease of space, as well as common area maintenance and parking. Under Topic 842, the lease of space is considered a lease component while the common area maintenance billings and tenant parking are considered nonlease components, which fall under revenue recognition guidance in Topic 606. However, upon adopting the guidance in Topic 842, the Company determined that its tenant leases met the criteria to apply the practical expedient provided by ASU 2018-11 to recognize the lease and non-lease components together as one single component. This conclusion was based on the consideration that 1) the timing and pattern of transfer of the nonlease components and associated lease component are the same, and 2) the lease component, if accounted for separately, would be classified as an operating lease. As the lease of space is the predominant component of the Company’s leasing arrangements, we accounted for all lease and non-lease components as one single component under Topic 842. As a result, the adoption of Topic 842 did not have any impact on the Company’s timing or pattern of recognition of rental revenues as compared to previous guidance. Transient daily parking revenue will be accounted for under the guidance in Topic 606 and included in other property income in our consolidated statements of operations. To reflect their recognition as one lease component, rental revenues, tenant reimbursements and other lease related property income related to leases that also meet the requirements of the practical expedient provided by ASU 2018-11 have been combined in one line item subsequent to the adoption of Topic 842 for the three and nine months ended September 30, 2019 in rental income on the Company’s consolidated statements of operations. In addition, under Topic 842, lessor costs for certain services directly reimbursed by tenants, which were previously presented on a net basis under previous guidance, are required to be presented on a gross basis in revenues and expenses. During the three and nine months ended September 30, 2019 , we incurred additional property expenses of $4.1 million and $10.1 million , respectively, for which we were reimbursed, that were not required to be grossed up under the previous guidance. We presented this amount on a gross basis within rental income and property expenses in the Company’s consolidated statements of operations as a result of the adoption, which had no impact on net income. Our rental income is mostly comprised of fixed contractual payments defined under the lease that, in most cases, escalate annually over the term of the lease at fixed rates. Additionally, rental income includes variable payments for tenant reimbursements of property-related expenses and payments based on a percentage of tenant’s sales. The table below sets forth the allocation of rental income between fixed and variable payments for the three and nine months ended September 30, 2019 : Three Months Ended Nine Months Ended September 30, 2019 September 30, 2019 (in thousands) Fixed lease payments $ 181,851 $ 526,678 Variable lease payments 30,470 82,654 Total rental income $ 212,321 $ 609,332 Leasing Costs Upon adoption of Topic 842, the Company elected to apply the package of practical expedients provided and did not reassess the following as of January 1, 2019: 1) whether any expired or existing contracts are or contain leases; 2) the lease classification for any expired or existing leases; and 3) initial direct costs for any existing leases. Under Topic 842, initial direct costs for both lessees and lessors would include only those costs that are incremental to the arrangement and would not have been incurred if the lease had not been obtained. As a result, beginning January 1, 2019, the Company will no longer capitalize internal leasing costs and third-party legal leasing costs and instead will expense these costs as incurred. These expenses are included in leasing costs and general and administrative expenses on our consolidated statements of operations in 2019. During the three and nine months ended September 30, 2019 , the Company expensed approximately $2.4 million and $8.4 million , respectively, of indirect leasing costs which would have been capitalized prior to the adoption of Topic 842. The election of the package of practical expedients described above permits us to continue to account for our leases that commenced before January 1, 2019 under the previously existing lease accounting guidance for the remainder of their lease terms, and to apply the new lease accounting guidance to leases commencing or modified after January 1, 2019. On January 1, 2019, we recognized a $3.1 million cumulative-effect adjustment, primarily related to internal leasing costs and legal leasing costs for tenant leases that had not commenced prior to that date, to increase distributions in excess of earnings for the Company and partners’ capital for the Operating Partnership in connection with our adoption of Topic 842. Allowances for Tenant and Deferred Rent Receivables Upon the adoption of Topic 842 on January 1, 2019, our determination of the adequacy of the Company’s allowances for tenant receivables includes a binary assessment of whether or not the amounts due under a tenant’s lease agreement are probable of collection. For such amounts that are deemed probable of collection, revenue continues to be recorded on a straight-line basis over the lease term. For such amounts that are deemed not probable of collection, revenue is recorded as the lesser of (i) the amount which would be recognized on a straight-line basis or (ii) cash that has been received from the tenant, with any tenant and deferred rent receivable balances charged as a direct write-off against rental income in the period of the change in the collectability determination. In addition, for tenant and deferred rent receivables deemed probable of collection we also may record an allowance under other authoritative GAAP depending upon our evaluation of the individual receivables, specific credit enhancements, current economic conditions, and other relevant factors. Such allowances are recorded as increases or decreases through rental income on our consolidated statements of operations. Lessee Accounting The Company’s ground leases are the primary contracts in which we are the lessee. Upon adoption of Topic 842 on January 1, 2019, the Company had four existing ground leases which were classified as operating leases. We elected to apply the practical expedient to use hindsight in determining the lease term of our existing ground leases. As discussed above, the Company also elected to apply the package of practical expedients provided by Topic 842 and therefore did not reassess the classification of these ground leases. Existing ground leases that commenced before the January 1, 2019 adoption date continued to be accounted for as operating leases, and the new guidance did not have a material impact on our recognition of ground lease expense or our results of operations. However, for periods beginning after January 1, 2019, we are now required to recognize a lease liability on our consolidated balance sheets equal to the present value of the minimum future lease payments required in accordance with each ground lease, as well as a right of use asset equal to the lease liability adjusted for above and below market intangibles and deferred leasing costs. The adoption of Topic 842 resulted in the recognition of right of use ground lease assets totaling $82.9 million and ground lease liabilities totaling $87.4 million on January 1, 2019. There was no material impact to our consolidated statements of operations or consolidated statements of cash flows as a result of adoption of this new guidance. For further information, refer to Note 11. For leases with a term of 12 months or less where we are the lessee, we made an accounting policy election by class of underlying asset not to recognize right of use lease assets and lease liabilities. We recognize lease expense for such leases generally on a straight-line basis over the lease term. The following are our updated significant accounting policies that have been affected by the adoption of Topic 842. Significant Accounting Policies Revenue Recognition and Allowances for Tenant and Deferred Rent Receivables We recognize revenue from rent, tenant reimbursements, parking and other lease-related revenue once all of the following criteria are met: (i) the agreement has been fully executed and delivered, (ii) services have been rendered, (iii) the amount is fixed or determinable and (iv) payment has been received or the collectability of the amount due is probable. Lease termination fees are amortized over the remaining lease term, if applicable. If there is no remaining lease term, they are recognized when received and realized. Minimum annual rental revenues are recognized in rental revenues on a straight-line basis over the non-cancellable term of the related lease. We carry our current and deferred rent receivables net of allowances for amounts that may not be collected. Prior to the adoption of Topic 842 on January 1, 2019, the allowances are increased or decreased through provision for bad debts on our consolidated statements of operations. Upon the adoption of Topic 842 on January 1, 2019, our determination of the adequacy of the Company's allowances for tenant receivables includes a binary assessment of whether or not the amounts due under a tenant’s lease agreement are probable of collection. For such amounts that are deemed probable of collection, revenue continues to be recorded on a straight-line basis over the lease term. For such amounts that are deemed not probable of collection, revenue is recorded as the lesser of (i) the amount which would be recognized on a straight-line basis or (ii) cash that has been received from the tenant, with any tenant and deferred rent receivable balances charged as a direct write-off against rental income in the period of the change in the collectability determination. In addition, for tenant and deferred rent receivables deemed probable of collection we also may record an allowance under other authoritative GAAP depending upon our evaluation of the individual receivables, specific credit enhancements, current economic conditions, and other relevant factors. Such allowances are recorded as increases or decreases through rental income on our consolidated statements of operations. For the three months ended September 30, 2019 , we recorded a provision for bad debts of $0.1 million . For the nine months ended September 30, 2019 , we recorded a net reversal of allowance for tenant and deferred rent receivables of $3.2 million primarily due to the improved credit quality of a tenant that we previously recorded a provision against during the nine months ended September 30, 2018 . For the three and nine months ended September 30, 2018 , we recorded a provision for bad debts of $1.3 million and $6.7 million , respectively, primarily related to this tenant. Rental revenue recognition commences when the tenant takes possession or controls the physical use of the leased space. In order for the tenant to take possession, the leased space must be substantially complete and ready for its intended use. In order to determine whether the leased space is substantially complete and ready for its intended use, we begin by determining whether the Company or the tenant owns the tenant improvements. When we conclude that the Company is the owner of tenant improvements, rental revenue recognition begins when the tenant takes possession of the finished space, which is generally when Company-owned tenant improvements are substantially complete. In certain instances, when we conclude that the Company is not the owner (the tenant is the owner) of tenant improvements, rental revenue recognition begins when the tenant takes possession or controls the physical use of the leased space. When we conclude that the Company is the owner of tenant improvements, we record the cost to construct the tenant improvements, including costs paid for or reimbursed by the tenants, as a capital asset. For these tenant improvements, we record the amount funded by or reimbursed by the tenants as deferred revenue, which is amortized on a straight-line basis as additional rental income over the term of the related lease. When we conclude that the tenant is the owner of tenant improvements for accounting purposes, we record our contribution towards those improvements as a lease incentive, which is included in deferred leasing costs and acquisition-related intangible assets, net on our consolidated balance sheets and amortized as a reduction to rental income on a straight-line basis over the term of the related lease. For residential properties, we commence revenue recognition upon lease commencement. Residential rental revenue is recognized on a straight-line basis over the term of the related lease, net of any concessions. Tenant Reimbursements Reimbursements from tenants, consisting of amounts due from tenants for common area maintenance, real estate taxes and other recoverable costs, are recognized in rental income subsequent to the adoption of Topic 842 in the period the recoverable costs are incurred. Tenant reimbursements where we pay the associated costs directly to third-party vendors and are reimbursed by our tenants are recognized and recorded on a gross basis. Other Property Income Other property income primarily includes amounts recorded in connection with transient daily parking, tenant bankruptcy settlement payments, broken deal income and property damage settlement related payments. Other property income also includes miscellaneous income from tenants, restoration fees and fees for late rental payments. Amounts recorded within other property income fall within the scope of Topic 606 and are accounted for at the point in time when control of the goods or services transfers to the customer and our performance obligation is satisfied. Accounting Pronouncements Effective in 2020 and Beyond ASU No. 2016-13 “Financial Instruments - Credit Losses (Topic 326)” 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. In November 2018, the FASB released ASU No. 2018-19 “Codification Improvements to Topic 326, Financial Instrument - Credit Losses.” This ASU clarifies that receivables arising from operating leases are not within the scope of Subtopic 326-20 “Financial Instruments – Credit Losses.” Instead, impairment of receivables arising from operating leases should be accounted for under Subtopic 842-30 “Leases – Lessor.” 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 anticipate that the guidance will have a material impact on its consolidated financial statements or notes to its consolidated financial statements. ASU No. 2018-13 “Fair Value Measurement (Topic 820)” On August 28, 2018, the FASB issued ASU No. 2018-13 (“ASU 2018-13”) to amend the disclosure requirements for fair value measurements. The amendments in ASU 2018-13 include new, modified and eliminated disclosure requirements and are the result of a broader disclosure project called FASB Concepts Statement, Conceptual Framework for Financial Reporting - Chapter 8: Notes to Financial Statements (the “Concepts Statement”), which the FASB finalized on August 28, 2018. The FASB used the guidance in the Concepts Statement to improve the effectiveness of Topic 820’s disclosure requirements. ASU 2018-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted for any eliminated or modified disclosures. The Company does not anticipate that the guidance will have a material impact on its consolidated financial statements or notes to its consolidated financial statements. ASU No. 2018-15 “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40)” On August 29, 2018, the FASB issued ASU No. 2018-15 (“ASU 2018-15”) to amend a customer’s accounting for implementation costs incurred in a cloud computing arrangement that is a service contract. ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). ASU 2018-15 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted, including adoption in any interim period. ASU 2018-15 can be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. The Company does not anticipate that the guidance will have a material impact on its consolidated financial statements or notes to its consolidated financial statements.

Organization, Ownership and B_3

Organization, Ownership and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of real estate properties	As of September 30, 2019 , the following properties were excluded from our stabilized portfolio. We did not have any redevelopment properties at September 30, 2019 . Number of Properties/Projects Estimated Rentable Square Feet (1) / Units Properties held for sale (2) 1 271,556 Completed residential development project (3) 1 237 units In-process development projects - tenant improvement (4) 2 846,000 In-process development projects - under construction (5) 6 2,295,000 ________________________ (1) Estimated rentable square feet upon completion. (2) See Note 3 “Dispositions and Real Estate Held for Sale” for additional information. (3) Represents our recently completed residential units that are not yet stabilized. (4) Includes 96,000 square feet of retail space. (5) In addition to the estimated office rentable square feet noted above, development projects under construction also include 564 residential units. Our stabilized portfolio of operating properties was comprised of the following properties at September 30, 2019 : Number of Buildings Rentable Square Feet Number of Tenants Percentage Occupied Percentage Leased Stabilized Office Properties 93 13,322,212 438 92.1 % 97.3 % Number of Number of Units 2019 Average Occupancy Stabilized Residential Property 1 200 78.5 %
Schedule of allocation of rental income between fixed and variable payments	The table below sets forth the allocation of rental income between fixed and variable payments for the three and nine months ended September 30, 2019 : Three Months Ended Nine Months Ended September 30, 2019 September 30, 2019 (in thousands) Fixed lease payments $ 181,851 $ 526,678 Variable lease payments 30,470 82,654 Total rental income $ 212,321 $ 609,332

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2019
Asset Acquisitions [Abstract]
Schedule of acquisitions	During the nine months ended September 30, 2019 , we acquired the following development properties listed below from an unrelated third party. The acquisition was funded with proceeds from the Company’s unsecured revolving credit facility. Property Date of Acquisition Submarket Type Purchase Price (in millions) (1) 1335 Broadway & 901 Park Boulevard, San Diego, CA August 19, 2019 East Village Land $ 40.0 ________________________ (1) Excludes acquisition-related costs.

Dispositions and Real Estate _2

Dispositions and Real Estate Held for Sale (Tables)	9 Months Ended
	Sep. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Schedule of operating property dispositions	The following table summarizes the operating property sold during the nine months ended September 30, 2019 : Property Month of Disposition Number of Buildings Rentable Square Feet Sales Price (in millions) (1) 2829 Townsgate Road, Thousand Oaks, CA May 1 84,098 $ 18.3 __________________ (1) Represents gross sales price before the impact of broker commissions and closing costs. The major classes of assets and liabilities of the property held for sale as of September 30, 2019 were as follows: Real estate assets and other assets held for sale (in thousands) Land and improvements $ 9,319 Buildings and improvements 90,147 Total real estate held for sale 99,466 Accumulated depreciation and amortization (29,420 ) Total real estate held for sale, net 70,046 Current receivables, net 79 Deferred rent receivables, net 1,288 Deferred leasing costs and acquisition-related intangibles, net 1,733 Prepaid expenses and other assets, net 4,605 Total real estate held for sale, net $ 77,751 Liabilities and deferred revenue of real estate assets held for sale Accounts payable and accrued expenses and other $ 3,658 Deferred revenue and acquisition-related intangible liabilities, net 122 Rents received in advance and tenant security deposits 1,131 Liabilities and deferred revenue of real estate assets held for sale $ 4,911
Schedule of real estate assets held for sale	As of September 30, 2019 , the following property was classified as held for sale: Property Submarket Property Type Number of Buildings Rentable Square Feet 2211 Michelson Drive, Irvine, CA Orange County Office 1 271,556

Prepaid Expenses and Other As_2

Prepaid Expenses and Other Assets, Net (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 and December 31, 2018 : September 30, 2019 December 31, 2018 (in thousands) Furniture, fixtures and other long-lived assets, net (1) $ 36,192 $ 36,833 Notes receivable, net (2) 1,598 2,113 Prepaid expenses & acquisition deposits (1)(3) 71,917 13,927 Total prepaid expenses and other assets, net $ 109,707 $ 52,873 ________________________ (1) Excludes amounts related to properties held for sale as of September 30, 2019 . (2) Notes receivable are shown net of a valuation allowance of approximately $3.6 million and $2.9 million as of September 30, 2019 and December 31, 2018 , respectively. (3) Includes $50.0 million of non-refundable acquisition deposits related to an acquisition which closed on October 15, 2019. Refer to Note 17 “Subsequent Events” for additional information.

Secured and Unsecured Debt of_2

Secured and Unsecured Debt of the Operating Partnership (Tables) - Kilroy Realty L.P. [Member]	9 Months Ended
	Sep. 30, 2019
Debt Instrument [Line Items]
Unsecured revolving credit facility	The following table summarizes the balance and terms of our unsecured revolving credit facility as of September 30, 2019 and December 31, 2018 : September 30, 2019 December 31, 2018 (in thousands) Outstanding borrowings $ — $ 45,000 Remaining borrowing capacity 750,000 705,000 Total borrowing capacity (1) $ 750,000 $ 750,000 Interest rate (2) 3.02 % 3.48 % Facility fee-annual rate (3) 0.200% Maturity date July 2022 ________________________ (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 the contractual rate of LIBOR plus 1.000% as of September 30, 2019 and December 31, 2018 . (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, 2019 and December 31, 2018 , $3.7 million and $4.7 million of unamortized deferred financing costs, respectively, which are included in prepaid expenses and other assets, net on our consolidated balance sheets, remained to be amortized through the maturity date of our unsecured revolving credit facility. The following table summarizes the balance and terms of our unsecured term loan facility as of September 30, 2019 and December 31, 2018 : September 30, 2019 December 31, 2018 (in thousands) Outstanding borrowings $ 150,000 $ 150,000 Remaining borrowing capacity — — Total borrowing capacity (1) $ 150,000 $ 150,000 Interest rate (2) 3.13 % 3.49 % Undrawn facility fee-annual rate (3) 0.200% Maturity date July 2022 ________________________ (1) As of September 30, 2019 and December 31, 2018 , $0.7 million and $0.9 million of unamortized deferred financing costs, respectively, remained to be amortized through the maturity date of our unsecured term loan facility. (2) Our unsecured term loan facility interest rate was calculated based on the contractual rate of LIBOR plus 1.100% as of September 30, 2019 and December 31, 2018 . (3) Prior to borrowing the full capacity of our unsecured term loan facility, the undrawn facility fee was calculated based on any unused borrowing capacity and was paid on a quarterly basis.
Schedule of debt maturities	The following table summarizes the stated debt maturities and scheduled amortization payments of our issued and outstanding debt as of September 30, 2019 : Year (in thousands) Remaining 2019 $ 465 2020 5,137 2021 5,342 2022 155,554 2023 305,775 2024 431,006 Thereafter 2,431,688 Total aggregate principal value (1) $ 3,334,967 ________________________ (1) Includes gross principal balance of outstanding debt before the effect of the following at September 30, 2019 : $21.1 million of unamortized deferred financing costs for the unsecured term loan facility, unsecured senior notes and secured debt and $6.7 million of unamortized discounts for the unsecured senior notes.
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, 2019 and 2018 . 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, 2019 2018 2019 2018 (in thousands) Gross interest expense $ 32,220 $ 30,231 $ 95,507 $ 85,834 Capitalized interest and deferred financing costs (20,585 ) (19,156 ) (60,902 ) (48,549 ) Interest expense $ 11,635 $ 11,075 $ 34,605 $ 37,285

Partners' Capital of the Oper_2

Partners' Capital of the Operating Partnership (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 December 31, 2018 September 30, 2018 Company owned common units in the Operating Partnership 106,011,916 100,746,988 100,746,988 Company owned general partnership interest 98.1 % 98.0 % 98.0 % Noncontrolling common units of the Operating Partnership 2,023,287 2,025,287 2,025,287 Ownership interest of noncontrolling interest 1.9 % 2.0 % 2.0 %

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Schedule of share-based payment award, restricted stock units, valuation assumptions	The determination of the grant date fair value of the portion of the 2019 Performance-Based RSU grants covered by the market condition was calculated using a Monte Carlo simulation pricing model based on the assumptions in the table below, which resulted in a $72.57 grant date fair value per share. Fair Value Assumptions Valuation date February 1, 2019 Expected share price volatility 19.0% Risk-free interest rate 2.48% Fair value per share on valuation date 72.57

Future Minimum Rent (Tables)

Future Minimum Rent (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Future contractual minimum rent under operating leases	Future contractual minimum rent under operating leases as of September 30, 2019 (under Topic 842) for future periods is summarized as follows: Year Ending (in thousands) Remaining 2019 $ 145,027 2020 665,314 2021 703,649 2022 735,969 2023 717,898 2024 681,026 Thereafter 3,607,437 Total (1) $ 7,256,320 ______________ (1) Excludes residential leases and leases with a term of one year or less. Future contractual minimum rent under operating leases as of December 31, 2018 for future periods is summarized as follows: Year Ending (in thousands) 2019 $ 566,783 2020 632,875 2021 631,835 2022 620,684 2023 586,371 Thereafter 3,240,143 Total (1) $ 6,278,691 ______________ (1) Excludes residential leases and leases with a term of one year or less.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Schedule of contractual expiration dates for ground leases	The following table summarizes our properties that are held subject to long-term noncancellable ground lease obligations and the respective contractual expiration dates: Property Contractual Expiration Date (1) 601 108th Ave NE, Bellevue, WA November 2093 701, 801 and 837 N. 34th Street, Seattle, WA (2) December 2041 1701 Page Mill Road and 3150 Porter Drive, Palo Alto, CA December 2067 Kilroy Airport Center Phases I, II, and III, Long Beach, CA July 2084 ____________________ (1) Reflects the contractual expiration date prior to the impact of any extension or purchase options held by the Company. (2) The Company has three 10 -year and one 45 -year extension options for this ground lease, which if exercised would extend the expiration date to December 2116. These extensions options are not assumed to be exercised in our calculation of the present value of the future minimum lease payments for this lease.
Schedule of future minimum rental repayments for ground leases	The minimum commitment under our ground leases as of September 30, 2019 (under Topic 842) for future periods is summarized as follows: Year Ending (in thousands) Remaining 2019 $ 1,301 2020 5,205 2021 5,205 2022 5,205 2023 5,205 2024 5,205 Thereafter 229,339 Total undiscounted cash flows (1)(2)(3)(4)(5) 256,665 Present value discount (169,048 ) Ground lease liabilities $ 87,617 ________________________ (1) Excludes contingent future rent payments based on gross income or adjusted gross income and reflects the minimum ground lease obligations before the impact of ground lease extension options. (2) One of our ground lease obligations is subject to a fair market value adjustment every five years ; however, the lease includes ground rent subprotection and infrastructure rent credits which currently limit our annual rental obligations to $1.0 million . The contractual obligations for that ground lease included above assumes the lesser of $1.0 million or annual lease rental obligation in effect as of September 30, 2019 . (3) One of our ground lease obligations includes a component which is based on the percentage of gross income that exceeds the minimum ground rent. The minimum rent is subject to increases every five years based on 50% of the average annual percentage rent for the previous five years. The contractual obligations for that lease included above assume the current annual ground lease obligation in effect at September 30, 2019 for the remainder of the lease term since we cannot predict future adjustments. (4) One of our ground lease obligations is subject to a fair market value adjustment every five years based on a combination of CPI adjustments and third-party appraisals limited to maximum increases annually. The contractual obligations for that lease included above assume the current annual ground lease obligation in effect at September 30, 2019 for the remainder of the lease term since we cannot predict future adjustments. (5) One of our ground lease obligations includes a component which is based on the percentage of adjusted gross income that exceeds the minimum ground rent. The minimum rent is subject to increases every ten years by an amount equal to 60% of the average annual percentage rent for the previous three years. The contractual obligations for this lease included above assume the current annual ground lease obligation in effect at September 30, 2019 for the remainder of the lease term since we cannot predict future adjustments. The minimum commitment under our ground leases as of December 31, 2018 for future periods is summarized as follows: Year Ending (in thousands) 2019 $ 5,154 2020 5,154 2021 5,154 2022 5,154 2023 5,154 Thereafter 233,619 Total (1)(2)(3)(4)(5) $ 259,389 ________________________ (1) Excludes contingent future rent payments based on gross income or adjusted gross income and reflects the minimum ground lease obligations before the impact of ground lease extension options. (2) One of our ground lease obligations is subject to a fair market value adjustment every five years ; however, the lease includes ground rent subprotection and infrastructure rent credits which currently limit our annual rental obligations to $1.0 million . The contractual obligations for that ground lease included above assumes the lesser of $1.0 million or annual lease rental obligation in effect as of December 31, 2018. (3) One of our ground lease obligations includes a component which is based on the percentage of gross income that exceeds the minimum ground rent. The minimum rent is subject to increases every five years based on 50% of the average annual percentage rent for the previous five years. The contractual obligations for that lease included above assume the current annual ground lease obligation in effect at December 31, 2018 for the remainder of the lease term since we cannot predict future adjustments. (4) One of our ground lease obligations is subject to a fair market value adjustment every five years based on a combination of CPI adjustments and third-party appraisals limited to maximum increases annually. The contractual obligations for that lease included above assume the current annual ground lease obligation in effect at December 31, 2018 for the remainder of the lease term since we cannot predict future adjustments. (5) One of our ground lease obligations includes a component which is based on the percentage of adjusted gross income that exceeds the minimum ground rent. The minimum rent is subject to increases every ten years by an amount equal to 60% of the average annual percentage rent for the previous three years. The contractual obligations for this lease included above assume the current annual ground lease obligation in effect at December 31, 2018 for the remainder of the lease term since we cannot predict future adjustments.

Fair Value Measurements and D_2

Fair Value Measurements and Disclosures (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 and December 31, 2018 : Fair Value (Level 1) (1) September 30, 2019 December 31, 2018 Description (in thousands) Marketable securities (2) $ 26,188 $ 21,779 ________________________ (1) Based on quoted prices in active markets for identical securities. (2) The marketable securities are held in a limited rabbi trust.
Net gain (loss) on marketable securities	The following table sets forth the net gain (loss) on marketable securities recorded during the three and nine months ended September 30, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Description (in thousands) (in thousands) Net gain on marketable securities $ 673 $ 271 $ 2,898 $ 289
Carrying value and fair value of company's remaining financial instruments	The following table sets forth the carrying value and the fair value of our other financial instruments as of September 30, 2019 and December 31, 2018 : September 30, 2019 December 31, 2018 Carrying Fair (1) Carrying Fair (1) (in thousands) Liabilities Secured debt, net $ 259,027 $ 271,224 $ 335,531 $ 335,885 Unsecured debt, net $ 3,048,209 $ 3,245,743 $ 2,552,070 $ 2,546,386 Unsecured line of credit $ — $ — $ 45,000 $ 45,058 ________________________ (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 Commo_3

Net Income Available to Common Stockholders Per Share of the Company (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands, except share and per share amounts) Numerator: Net income attributable to Kilroy Realty Corporation $ 43,846 $ 34,400 $ 122,943 $ 98,195 Allocation to participating securities (1) (530 ) (507 ) (1,582 ) (1,492 ) Numerator for basic and diluted net income available to common stockholders $ 43,316 $ 33,893 $ 121,361 $ 96,703 Denominator: Basic weighted average vested shares outstanding 104,841,176 100,676,778 102,252,739 99,711,312 Effect of dilutive securities 518,728 551,556 619,697 497,333 Diluted weighted average vested shares and common share equivalents outstanding 105,359,904 101,228,334 102,872,436 100,208,645 Basic earnings per share: Net income available to common stockholders per share $ 0.41 $ 0.34 $ 1.19 $ 0.97 Diluted earnings per share: Net income available to common stockholders per share $ 0.41 $ 0.33 $ 1.18 $ 0.97 ________________________ (1)

Net Income Available to Commo_4

Net Income Available to Common Unitholders Per Unit of the Operating Partnership (Tables)	9 Months Ended
	Sep. 30, 2019
Net Income Available To Common Unitholders [Line Items]
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, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands, except share and per share amounts) Numerator: Net income attributable to Kilroy Realty Corporation $ 43,846 $ 34,400 $ 122,943 $ 98,195 Allocation to participating securities (1) (530 ) (507 ) (1,582 ) (1,492 ) Numerator for basic and diluted net income available to common stockholders $ 43,316 $ 33,893 $ 121,361 $ 96,703 Denominator: Basic weighted average vested shares outstanding 104,841,176 100,676,778 102,252,739 99,711,312 Effect of dilutive securities 518,728 551,556 619,697 497,333 Diluted weighted average vested shares and common share equivalents outstanding 105,359,904 101,228,334 102,872,436 100,208,645 Basic earnings per share: Net income available to common stockholders per share $ 0.41 $ 0.34 $ 1.19 $ 0.97 Diluted earnings per share: Net income available to common stockholders per share $ 0.41 $ 0.33 $ 1.18 $ 0.97 ________________________ (1)
Kilroy Realty L.P. [Member]
Net Income Available To Common Unitholders [Line Items]
Net income available to common stockholders	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, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands, except unit and per unit amounts) Numerator: Net income attributable to Kilroy Realty, L.P. $ 44,589 $ 34,993 $ 124,998 $ 99,901 Allocation to participating securities (1) (530 ) (507 ) (1,582 ) (1,492 ) Numerator for basic and diluted net income available to common unitholders $ 44,059 $ 34,486 $ 123,416 $ 98,409 Denominator: Basic weighted average vested units outstanding 106,864,463 102,721,806 104,276,187 101,773,540 Effect of dilutive securities 518,728 551,556 619,697 497,333 Diluted weighted average vested units and common unit equivalents outstanding 107,383,191 103,273,362 104,895,884 102,270,873 Basic earnings per unit: Net income available to common unitholders per unit $ 0.41 $ 0.34 $ 1.18 $ 0.97 Diluted earnings per unit: Net income available to common unitholders per unit $ 0.41 $ 0.33 $ 1.18 $ 0.96 ________________________ (1)

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information of the Company (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 2018 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $58,337 and $46,761 as of September 30, 2019 and 2018, respectively $ 28,139 $ 32,175 Cash paid for amounts included in the measurement of ground lease liabilities $ 3,917 $ 3,598 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 148,468 $ 142,133 Assumption of accrued liabilities in connection with acquisitions $ 3,967 $ 40,624 Tenant improvements funded directly by tenants $ 10,254 $ 7,211 Initial measurement of operating right of use ground lease assets $ 82,938 $ — Initial measurement of operating ground lease liabilities $ 87,409 $ — NON-CASH FINANCING TRANSACTIONS: Accrual of dividends and distributions payable to common stockholders and common unitholders $ 53,205 $ 47,411 Exchange of common units of the Operating Partnership into shares of the Company’s common stock $ 78 $ 1,962
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, 2019 and 2018 . Nine Months Ended September 30, 2019 2018 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 51,604 $ 57,649 Restricted cash at beginning of period 119,430 9,149 Cash and cash equivalents and restricted cash at beginning of period $ 171,034 $ 66,798 Cash and cash equivalents at end of period $ 297,620 $ 86,517 Restricted cash at end of period 6,300 — Cash and cash equivalents and restricted cash at end of period $ 303,920 $ 86,517
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, 2019 and 2018 . Nine Months Ended September 30, 2019 2018 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 51,604 $ 57,649 Restricted cash at beginning of period 119,430 9,149 Cash and cash equivalents and restricted cash at beginning of period $ 171,034 $ 66,798 Cash and cash equivalents at end of period $ 297,620 $ 86,517 Restricted cash at end of period 6,300 — Cash and cash equivalents and restricted cash at end of period $ 303,920 $ 86,517

Supplemental Cash Flow Inform_4

Supplemental Cash Flow Information of the Operating Partnership (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 2018 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $58,337 and $46,761 as of September 30, 2019 and 2018, respectively $ 28,139 $ 32,175 Cash paid for amounts included in the measurement of ground lease liabilities $ 3,917 $ 3,598 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 148,468 $ 142,133 Assumption of accrued liabilities in connection with acquisitions $ 3,967 $ 40,624 Tenant improvements funded directly by tenants $ 10,254 $ 7,211 Initial measurement of operating right of use ground lease assets $ 82,938 $ — Initial measurement of operating ground lease liabilities $ 87,409 $ — NON-CASH FINANCING TRANSACTIONS: Accrual of dividends and distributions payable to common stockholders and common unitholders $ 53,205 $ 47,411 Exchange of common units of the Operating Partnership into shares of the Company’s common stock $ 78 $ 1,962
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, 2019 and 2018 . Nine Months Ended September 30, 2019 2018 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 51,604 $ 57,649 Restricted cash at beginning of period 119,430 9,149 Cash and cash equivalents and restricted cash at beginning of period $ 171,034 $ 66,798 Cash and cash equivalents at end of period $ 297,620 $ 86,517 Restricted cash at end of period 6,300 — Cash and cash equivalents and restricted cash at end of period $ 303,920 $ 86,517
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, 2019 and 2018 . Nine Months Ended September 30, 2019 2018 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 51,604 $ 57,649 Restricted cash at beginning of period 119,430 9,149 Cash and cash equivalents and restricted cash at beginning of period $ 171,034 $ 66,798 Cash and cash equivalents at end of period $ 297,620 $ 86,517 Restricted cash at end of period 6,300 — Cash and cash equivalents and restricted cash at end of period $ 303,920 $ 86,517
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, 2019 2018 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $58,337 and $46,761 as of September 30, 2019 and 2018, respectively $ 28,139 $ 32,175 Cash paid for amounts included in the measurement of ground lease liabilities $ 3,917 $ 3,598 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 148,468 $ 142,133 Assumption of accrued liabilities in connection with acquisitions $ 3,967 $ 40,624 Tenant improvements funded directly by tenants $ 10,254 $ 7,211 Initial measurement of operating right of use ground lease assets $ 82,938 $ — Initial measurement of operating ground lease liabilities $ 87,409 $ — NON-CASH FINANCING TRANSACTIONS: Accrual of distributions payable to common unitholders $ 53,205 $ 47,411
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, 2019 and 2018 . Nine Months Ended September 30, 2019 2018 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 51,604 $ 57,649 Restricted cash at beginning of period 119,430 9,149 Cash and cash equivalents and restricted cash at beginning of period $ 171,034 $ 66,798 Cash and cash equivalents at end of period $ 297,620 $ 86,517 Restricted cash at end of period 6,300 — Cash and cash equivalents and restricted cash at end of period $ 303,920 $ 86,517
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, 2019 and 2018 . Nine Months Ended September 30, 2019 2018 RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 51,604 $ 57,649 Restricted cash at beginning of period 119,430 9,149 Cash and cash equivalents and restricted cash at beginning of period $ 171,034 $ 66,798 Cash and cash equivalents at end of period $ 297,620 $ 86,517 Restricted cash at end of period 6,300 — Cash and cash equivalents and restricted cash at end of period $ 303,920 $ 86,517

Organization, Ownership and B_4

Organization, Ownership and Basis of Presentation - Operating Properties (Details) - Sep. 30, 2019	building	property	ft²	tenant	project	residential_unit	Total
Stabilized office properties [Member]
Real Estate Properties [Line Items]
Number of Buildings	93	4
Rentable Square Feet | ft²			13,322,212
Number of Tenants | tenant				438
Percentage Occupied							92.10%
Percentage Leased							97.30%
Stabilized residential properties [Member]
Real Estate Properties [Line Items]
Number of Buildings | building	1
Percentage Occupied							78.50%
Number of Units | building	200
Properties held for sale [Member]
Real Estate Properties [Line Items]
Number of Buildings | project					1
Completed residential development project [Member]
Real Estate Properties [Line Items]
Number of Buildings | project					1
Rentable units | residential_unit						237
In-process development projects - tenant improvement [Member]
Real Estate Properties [Line Items]
Number of Buildings | project					2
Rentable Square Feet | ft²			846,000
In-process development projects - under construction [Member]
Real Estate Properties [Line Items]
Number of Buildings | project					6
Rentable Square Feet | ft²			2,295,000
In-process development projects - under construction [Member] | Retail site [Member]
Real Estate Properties [Line Items]
Rentable Square Feet | ft²			96,000
Number of residential units | residential_unit						564

Organization, Ownership and B_5

Organization, Ownership and Basis of Presentation - Narrative (Details) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2019USD ($)	Dec. 31, 2018USD ($)VIE	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019VIE	Sep. 30, 2019building	Sep. 30, 2019property	Sep. 30, 2019ft²	Sep. 30, 2019a	Sep. 30, 2019entity	Sep. 30, 2019property_partnership	Sep. 30, 2019project	Sep. 30, 2019	Jan. 01, 2019USD ($)ground_lease
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Lease-up properties occupancy percentage				95.00%
Lease-up properties occupancy duration				1 year
Number of VIEs | VIE		3				5
Number of entities established | entity											3
VIE assets	$ 552,400	$ 615,400		$ 552,400
VIE liabilities	36,300	45,100		36,300
Noncontrolling interest in VIE	193,467	192,363		193,467
Lease income	212,321			609,332
Leasing costs	1,192		$ 0	5,599	$ 0
Number of ground leases | ground_lease															4
Initial measurement of operating right of use ground lease assets	83,200			83,200											$ 82,938
Initial measurement of operating ground lease liabilities	87,617			87,617											87,409
Provision for bad debts	0		1,338	0	6,714
Accounting Standards Update 2016-02 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Leasing costs	2,400			8,400
Cumulative adjustment															3,146
Provision for bad debts	100		$ 1,300	(3,200)	$ 6,700
Accounting Standards Update 2016-02 [Member] | Property expense reimbursement [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Lease income	4,100			$ 10,100
San Francisco, California [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties | building							1
Stabilized office properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties							93	4
Area of undeveloped land | a										60
Stabilized office properties [Member] | Washington [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties | property								8
Stabilized office properties [Member] | Development project in San Francisco [Member] | San Francisco, California [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Area of real estate property | ft²									394,340
Development properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of property partnerships | property_partnership												3
Number of VIEs | VIE						2
Development properties [Member] | Washington [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties | property								1
Development properties [Member] | Development project in San Francisco [Member] | San Francisco, California [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties | property								1
Development sites [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties | project													4
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	434,500	543,900		$ 434,500
101 First LLC and 303 Second LLC [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Company owned general partnership interest														56.00%
Noncontrolling interest in VIE	$ 187,600	$ 186,400		$ 187,600
101 First LLC and 303 Second LLC [Member] | Development properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of property partnerships | property_partnership												2
Redwood LLC [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties | property								2
Company owned general partnership interest														93.00%
Operating Partnership [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Ownership interest		98.00%	98.00%	98.10%
Distributions in Excess of Earnings [Member] | Accounting Standards Update 2016-02 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Cumulative adjustment															$ 3,146
Non-affiliated investors and certain of our executive officers and directors [Member] | Operating Partnership [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Ownership interest		2.00%	2.00%	1.90%
Kilroy Realty Finance, Inc. [Member] | Finance Partnership [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%
Operating Partnership [Member] | Finance Partnership [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Ownership interest				99.00%

Organization, Ownership and B_6

Organization, Ownership and Basis of Presentation - Allocation of Rental Income (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Operating Lease, Lease Income [Abstract]
Fixed lease payments	$ 181,851	$ 526,678
Variable lease payments	30,470	82,654
Total rental income	$ 212,321	$ 609,332

Acquisitions (Details)

Acquisitions (Details) $ in Millions	Aug. 19, 2019USD ($)
1335 Broadway & 901 Park Boulevard, San Diego, CA [Member]
Schedule of Asset Acquisitions, by Acquisition [Line Items]
Purchase Price (in millions)	$ 40

Dispositions and Real Estate _3

Dispositions and Real Estate Held for Sale - Operating Property Dispositions (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)ft²building	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)ft²building	Sep. 30, 2018USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gains on sales of operating properties	$ 0	$ 0	$ 7,169	$ 0
Operating Properties [Member] | 2829 Townsgate Road, Thousand Oaks, CA [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties | building	1		1
Rentable square feet | ft²	84,098		84,098
Sales price			$ 18,300

Dispositions and Real Estate _4

Dispositions and Real Estate Held for Sale - Real Estate Assets Held for Sale (Details) - Real Estate Assets Held for Sale [Member]	Sep. 30, 2019ft²buildingproject
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings | project	1
2211 Michelson Drive, Irvine, CA [Member] | Held for sale [Member] | Office [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings | building	1
Rentable square feet | ft²	271,556

Dispositions and Real Estate _5

Dispositions and Real Estate Held for Sale - Major Classes of Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Real estate assets and other assets held for sale
Total real estate held for sale, net	$ 77,751
Liabilities and deferred revenue of real estate assets held for sale
Deferred revenue and acquisition-related intangible liabilities, net	134,828	$ 149,646
Rents received in advance and tenant security deposits	57,428	60,225
Liabilities and deferred revenue of real estate assets held for sale	4,911	$ 0
Held for sale [Member]
Real estate assets and other assets held for sale
Real estate held for sale	99,466
Accumulated depreciation and amortization	(29,420)
Total real estate held for sale, net	70,046
Current receivables, net	79
Deferred rent receivables, net	1,288
Deferred leasing costs and acquisition-related intangibles, net	1,733
Prepaid expenses and other assets, net	4,605
Total real estate held for sale, net	77,751
Liabilities and deferred revenue of real estate assets held for sale
Accounts payable and accrued expenses and other	3,658
Deferred revenue and acquisition-related intangible liabilities, net	122
Rents received in advance and tenant security deposits	1,131
Liabilities and deferred revenue of real estate assets held for sale	4,911
Land and improvements [Member] | Held for sale [Member]
Real estate assets and other assets held for sale
Real estate held for sale	9,319
Buildings and improvements [Member] | Held for sale [Member]
Real estate assets and other assets held for sale
Real estate held for sale	$ 90,147

Prepaid Expenses and Other As_3

Prepaid Expenses and Other Assets, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Prepaid Expense and Other Assets [Abstract]
Furniture, fixtures and other long-lived assets, net	$ 36,192	$ 36,833
Note receivable	1,598	2,113
Prepaid expenses & acquisition deposits	71,917	13,927
Total prepaid expenses and other assets, net	109,707	52,873
Non-refundable acquisition deposit	3,600	$ 2,900
Non-refundable acquisition deposit	$ 50,000

Secured and Unsecured Debt of_3

Secured and Unsecured Debt of the Operating Partnership - Narrative (Details) - Kilroy Realty L.P. [Member] - USD ($)	Feb. 11, 2019	Sep. 30, 2019
Secured debt [Member] | Mortgage payable [Member]
Debt Instrument [Line Items]
Repayments of notes payable	$ 74,300,000
Unsecured debt [Member] | Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt, principal		$ 500,000,000
Debt issuance discount		$ (600,000)
Maturity date		Feb. 15, 2030
Stated interest rate		3.05%

Secured and Unsecured Debt of_4

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, 2019	Dec. 31, 2018
Terms of the Credit Facility
Outstanding borrowings	$ 0	$ 45,000,000
Kilroy Realty L.P. [Member]
Terms of the Credit Facility
Outstanding borrowings	0	45,000,000
Unamortized deferred financing costs	21,100,000
Kilroy Realty L.P. [Member] | Revolving credit facility [Member]
Terms of the Credit Facility
Outstanding borrowings	0	45,000,000
Remaining borrowing capacity	750,000,000	705,000,000
Total borrowing capacity	$ 750,000,000	$ 750,000,000
Interest rate (percent)	3.02%	3.48%
Facility fee-annual rate (percent)	0.20%	0.20%
Contingent additional borrowings	$ 600,000,000
Unamortized deferred financing costs	$ 3,700,000	$ 4,700,000
Kilroy Realty L.P. [Member] | Revolving credit facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Terms of the Credit Facility
Variable rate (percent)	1.00%	1.00%
Kilroy Realty L.P. [Member] | Line of credit [Member] | $150 Million Term Loan Facility [Member]
Terms of the Credit Facility
Outstanding borrowings	$ 150,000,000	$ 150,000,000
Remaining borrowing capacity	0	0
Total borrowing capacity	$ 150,000,000	$ 150,000,000
Interest rate (percent)	3.13%	3.49%
Undrawn facility fee-annual rate (percent)	0.20%	0.20%
Unamortized deferred financing costs	$ 700,000	$ 900,000
Kilroy Realty L.P. [Member] | Line of credit [Member] | $150 Million Term Loan Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Terms of the Credit Facility
Variable rate (percent)	1.10%	1.10%

Secured and Unsecured Debt of_5

Secured and Unsecured Debt of the Operating Partnership - Debt Maturities (Details) - Kilroy Realty L.P. [Member] $ in Thousands	Sep. 30, 2019USD ($)
Stated debt maturities and scheduled amortization payments, excluding debt discounts
Remaining 2019	$ 465
2020	5,137
2021	5,342
2022	155,554
2023	305,775
2024	431,006
Thereafter	2,431,688
Total debt	3,334,967
Unamortized deferred financing costs	(21,100)
Unsecured senior notes [Member]
Stated debt maturities and scheduled amortization payments, excluding debt discounts
Unamortized discount	$ (6,700)

Secured and Unsecured Debt of_6

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Capitalized Interest and Loan Fees [Line Items]
Interest expense	$ 11,635	$ 11,075	$ 34,605	$ 37,285
Kilroy Realty L.P. [Member]
Capitalized Interest and Loan Fees [Line Items]
Gross interest expense	32,220	30,231	95,507	85,834
Capitalized interest and deferred financing costs	(20,585)	(19,156)	(60,902)	(48,549)
Interest expense	$ 11,635	$ 11,075	$ 34,605	$ 37,285

Stockholders' Equity of the C_2

Stockholders' Equity of the Company (Details) - USD ($)	1 Months Ended	9 Months Ended
	Aug. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Jun. 30, 2018
Class of Stock [Line Items]
Common stock, shares issued (in shares)		106,011,916		100,746,988
Shares issued, value		$ 1,060,000		$ 1,007,000
Proceeds from issuance of stock		$ 353,904,000	$ 130,744,000
Forward equity sale [Member]
Class of Stock [Line Items]
Price per share (in dollars per share)	$ 72.10
Shares issued, value	$ 360,500,000
Proceeds from issuance of stock	$ 354,300,000
Common Stock [Member] | Forward equity sale [Member]
Class of Stock [Line Items]
Number of shares issued (in shares)	5,000,000
At-The-Market Program [Member]
Class of Stock [Line Items]
At the market stock offering aggregate gross sales price of common stock					$ 500,000,000
At-The-Market Program [Member] | Common Stock [Member] | Forward equity sale [Member]
Class of Stock [Line Items]
Shares available for sale (in shares)		1,201,204
Price per share (in dollars per share)		$ 75.92
Common stock, shares issued (in shares)		447,466
At the market stock offering remaining amount available for issuance		$ 375,000,000

Noncontrolling Interests on t_2

Noncontrolling Interests on the Company's Consolidated Financial Statements - Common Units of the Operating Partnership (Details) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2018USD ($)$ / sharesshares	Sep. 30, 2018shares	Sep. 30, 2019USD ($)trading_day$ / sharesshares
Noncontrolling Interest [Line Items]
Common stock, par value (in dollars per share) | $ / shares	$ 0.01		$ 0.01
Number of trading days | trading_day			10
Aggregate value upon redemption of outstanding noncontrolling common units | $	$ 126.4		$ 158
Non-affiliated investors and certain of our executive officers and directors [Member] | Common units [Member]
Noncontrolling Interest [Line Items]
Common units outstanding held by common limited partners (in units)	2,025,287	2,025,287	2,023,287
Kilroy Realty L.P. [Member] | Common units [Member]
Noncontrolling Interest [Line Items]
Common units outstanding held by common limited partners (in units)	2,025,287		2,023,287
Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Ownership interest	98.00%	98.00%	98.10%
Operating Partnership [Member] | Non-affiliated investors and certain of our executive officers and directors [Member]
Noncontrolling Interest [Line Items]
Ownership interest	2.00%	2.00%	1.90%

Partners' Capital of the Oper_3

Partners' Capital of the Operating Partnership (Details) - shares	3 Months Ended		9 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2019
Operating Partnership [Member]
General Partners' Capital Account [Abstract]
Ownership interest	98.00%	98.00%	98.10%
Kilroy Realty L.P. [Member] | Common units [Member]
General Partners' Capital Account [Abstract]
Company owned common units in the Operating Partnership	100,746,988	100,746,988	106,011,916
Noncontrolling common units of the Operating Partnership	2,025,287		2,023,287
Non-affiliated investors and certain of our executive officers and directors [Member] | Operating Partnership [Member]
General Partners' Capital Account [Abstract]
Ownership interest	2.00%	2.00%	1.90%
Non-affiliated investors and certain of our executive officers and directors [Member] | Common units [Member]
General Partners' Capital Account [Abstract]
Noncontrolling common units of the Operating Partnership	2,025,287	2,025,287	2,023,287

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions	Feb. 01, 2019USD ($)$ / sharesshares	Feb. 28, 2019installmentshares	Sep. 30, 2019USD ($)compensation_planshares	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)compensation_planshares	Sep. 30, 2018USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share-based incentive compensation plans | compensation_plan			1		1
Share-based compensation expense | $			$ 6.8	$ 8.1	$ 24.4	$ 24.7
Share-based compensation expense capitalized | $			0.7	$ 1.5	4.2	$ 5.8
Share-based compensation not yet recognized | $			$ 57.4		$ 57.4
Share-based compensation not yet recognized period of recognition					2 years 4 months 24 days
2019 Time-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Number of installments | installment		3
Right to receive number of shares (in shares)	1
Time-Based Restricted Stock Units (RSUs), 2019 Time-Based RSU Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value RSUs granted | $	$ 10.1
2019 Performance-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years			3 years
Vesting, achievement of pre-set FFO per share goals, percentage of RSUs			100.00%		100.00%
Vesting, Average debt to EBIDTA ratio, percentage of RSUs			50.00%		50.00%
Vesting, Market measure, percentage of RSUs			50.00%		50.00%
Number of shares issuable per RSU		1
Share price | $ / shares	$ 69.89
Fair value per share on valuation date | $ / shares	$ 72.57
Remaining expected life, including future volatility		5 years 9 months 18 days
Fair value per share on valuation date		2 years 10 months 24 days
Fair value RSUs granted | $	$ 10.2
Kilroy Realty 2006 Incentive Award Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Effective registration shares (in shares)			9,200,000		9,200,000
Number of shares available for grant (in shares)			400,000		400,000
Executive Officer share-based compensation programs [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted in period (in shares)		288,378
Executive Officer share-based compensation programs [Member] | Market Measure-Based Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted in period (in shares)		143,396
Executive Officer share-based compensation programs [Member] | Time-Based Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted in period (in shares)		144,982
Executive Officer share-based compensation programs [Member] | 2019 Time-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares forfeited (in shares)			10,733
Executive Officer share-based compensation programs [Member] | 2019 Performance-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares forfeited (in shares)			16,235
Executive Officer share-based compensation programs [Member] | Time-Based RSUs and Performance-Based RSUs, granted in prior years [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares forfeited (in shares)			98,569
Market measure-based RSU estimate of probable [Member] | Market Measure-Based Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Capital shares reserved for future issuance (in shares)			207,138		207,138

Share-Based Compensation - Fair

Share-Based Compensation - Fair Value Assumptions (Details) - 2018 Performance-Based RSUs [Member]	Feb. 01, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected share price volatility	19.00%
Risk-free interest rate	2.48%

Future Minimum Rent - Future Co

Future Minimum Rent - Future Contractual Minimum Rent (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Future contractual minimum rent under operating lease
Remaining 2019	$ 145,027
2020	665,314
2021	703,649
2022	735,969
2023	717,898
2024	681,026
Thereafter	3,607,437
Total	$ 7,256,320
Future contractual minimum rent under operating lease
2019		$ 566,783
2020		632,875
2021		631,835
2022		620,684
2023		586,371
Thereafter		3,240,143
Total		$ 6,278,691

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)ground_lease	Dec. 31, 2018USD ($)	Jan. 01, 2019USD ($)
Long-term Purchase Commitment [Line Items]
Commitments for contracts and executed leases, operating and redevelopment and development properties	$ 1,200,000	$ 1,200,000
Weighted average discount rate, ground leases	5.15%	5.15%
Initial measurement of operating right of use ground lease assets	$ 83,200	$ 83,200		$ 82,938
Initial measurement of operating ground lease liabilities	$ 87,617	$ 87,617		$ 87,409
Weighted average remaining lease term	51 years	51 years
Variable lease, cost	$ 700	$ 2,300
Period after which ground lease rentals are adjusted based on fair market value and the Consumer Price Index		5 years	5 years
Annual ground lease rental obligations limit		$ 1,000	$ 1,000
Average annual percentage rent for previous five years (percent)		50.00%	50.00%
Duration of ground lease prior to increase ten years		10 years
Average annual percentage rent for previous ten years (percent)		60.00%	60.00%
Environmental matters [Member]
Long-term Purchase Commitment [Line Items]
Accrued environmental remediation liabilities	$ 75,100	$ 75,100
Ten year ground lease extension option [Member]
Long-term Purchase Commitment [Line Items]
Number of extension options | ground_lease		3
Ground lease extension option term			10 years
Forty-five year ground lease extension option [Member]
Long-term Purchase Commitment [Line Items]
Number of extension options | ground_lease		1
Ground lease extension option term		45 years

Commitments and Contingencies_2

Commitments and Contingencies - Minimum Commitment Under Ground Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Minimum commitment under our ground leases
Remaining 2019	$ 1,301
2020	5,205
2021	5,205
2022	5,205
2023	5,205
2024	5,205
Thereafter	229,339
Total undiscounted cash flows	256,665
Present value discount	(169,048)
Initial measurement of operating ground lease liabilities	$ 87,617	$ 87,409
Minimum commitment under our ground leases
2019			$ 5,154
2020			5,154
2021			5,154
2022			5,154
2023			5,154
Thereafter			233,619
Total			$ 259,389

Fair Value Measurements and D_3

Fair Value Measurements and Disclosures - Assets and Liabilities Reported at Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Fair value adjustment of marketable securities and deferred compensation plan liability
Net gain on marketable securities	$ 673	$ 271	$ 2,898	$ 289
Fair value, measurements, recurring [Member] | Fair value (Level 1) [Member]
Assets and Liabilities Reported at Fair Value
Marketable securities	$ 26,188		$ 26,188		$ 21,779

Fair Value Measurements and D_4

Fair Value Measurements and Disclosures - Financial Instruments Disclosed at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Carrying value [Member] | Secured debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt, net	$ 259,027	$ 335,531
Carrying value [Member] | Unsecured debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt, net	3,048,209	2,552,070
Carrying value [Member] | Line of credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt, net	0	45,000
Fair value [Member] | Secured debt [Member] | Fair value (level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt, net	271,224	335,885
Fair value [Member] | Unsecured debt [Member] | Fair value (level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt, net	3,245,743	2,546,386
Fair value [Member] | Line of credit [Member] | Fair value (level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt, net	$ 0	$ 45,058

Net Income Available to Commo_5

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator:
Net income attributable to Kilroy Realty Corporation	$ 43,846	$ 34,400	$ 122,943	$ 98,195
Allocation to participating securities	(530)	(507)	(1,582)	(1,492)
Numerator for basic and diluted net income available to common stockholders	$ 43,316	$ 33,893	$ 121,361	$ 96,703
Denominator:
Basic weighted average vested shares outstanding (in shares)	104,841,176	100,676,778	102,252,739	99,711,312
Effect of dilutive securities (in shares)	518,728	551,556	619,697	497,333
Diluted weighted average vested shares and common share equivalents outstanding (in shares)	105,359,904	101,228,334	102,872,436	100,208,645
Basic earnings per share:
Net income available to common stockholders per share (in dollars per share)	$ 0.41	$ 0.34	$ 1.19	$ 0.97
Diluted earnings per share:
Net income available to common stockholders per share (in dollars per share)	$ 0.41	$ 0.33	$ 1.18	$ 0.97

Net Income Available to Commo_6

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator:
Net income attributable to Kilroy Realty, L.P.	$ 43,846	$ 34,400	$ 122,943	$ 98,195
Allocation to participating securities	(530)	(507)	(1,582)	(1,492)
Numerator for basic and diluted net income available to common stockholders	$ 43,316	$ 33,893	$ 121,361	$ 96,703
Denominator:
Basic weighted average vested shares outstanding (in shares)	104,841,176	100,676,778	102,252,739	99,711,312
Effect of dilutive securities (in units)	518,728	551,556	619,697	497,333
Diluted weighted average vested shares and common share equivalents outstanding (in shares)	105,359,904	101,228,334	102,872,436	100,208,645
Basic earnings per unit:
Net income available to common stockholders per share (in dollars per share)	$ 0.41	$ 0.34	$ 1.19	$ 0.97
Diluted earnings per unit:
Net income available to common stockholders per share (in dollars per share)	$ 0.41	$ 0.33	$ 1.18	$ 0.97
Kilroy Realty L.P. [Member]
Numerator:
Net income attributable to Kilroy Realty, L.P.	$ 44,589	$ 34,993	$ 124,998	$ 99,901
Allocation to participating securities	(530)	(507)	(1,582)	(1,492)
Numerator for basic and diluted net income available to common stockholders	$ 44,059	$ 34,486	$ 123,416	$ 98,409
Denominator:
Basic weighted average vested shares outstanding (in shares)	106,864,463	102,721,806	104,276,187	101,773,540
Effect of dilutive securities (in units)	518,728	551,556	619,697	497,333
Diluted weighted average vested shares and common share equivalents outstanding (in shares)	107,383,191	103,273,362	104,895,884	102,270,873
Basic earnings per unit:
Net income available to common stockholders per share (in dollars per share)	$ 0.41	$ 0.34	$ 1.18	$ 0.97
Diluted earnings per unit:
Net income available to common stockholders per share (in dollars per share)	$ 0.41	$ 0.33	$ 1.18	$ 0.96

Supplemental Cash Flow Inform_5

Supplemental Cash Flow Information of the Company - Supplemental Cash Flow (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019
SUPPLEMENTAL CASH FLOWS INFORMATION:
Cash paid for interest, net of capitalized interest of $58,337 and $46,761 as of September 30, 2019 and 2018, respectively	$ 28,139	$ 32,175
Capitalized interest	58,337	46,761
Cash paid for amounts included in the measurement of ground lease liabilities	3,917	3,598
NON-CASH INVESTING TRANSACTIONS:
Accrual for expenditures for operating properties and development properties	148,468	142,133
Assumption of accrued liabilities in connection with acquisitions	3,967	40,624
Tenant improvements funded directly by tenants	10,254	7,211
Initial measurement of operating right of use ground lease assets	83,200		$ 82,938
Initial measurement of operating ground lease liabilities	87,617		$ 87,409
NON-CASH FINANCING TRANSACTIONS:
Accrual of dividends and distributions payable to common stockholders and common unitholders	53,205	47,411
Exchange of common units of the Operating Partnership into shares of the Company’s common stock	$ 78	$ 1,962

Supplemental Cash Flow Inform_6

Supplemental Cash Flow Information of the Company - Reconciliation of Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH:
Cash and cash equivalents	$ 297,620	$ 51,604	$ 86,517	$ 57,649
Restricted cash	6,300	119,430	0	9,149
Cash and cash equivalents and restricted cash	$ 303,920	$ 171,034	$ 86,517	$ 66,798

Supplemental Cash Flow Inform_7

Supplemental Cash Flow Information of the Operating Partnership - Supplemental Cash Flow (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019
SUPPLEMENTAL CASH FLOWS INFORMATION:
Cash paid for interest, net of capitalized interest of $58,337 and $46,761 as of September 30, 2019 and 2018, respectively	$ 28,139	$ 32,175
Capitalized interest	58,337	46,761
Cash paid for amounts included in the measurement of ground lease liabilities	3,917	3,598
NON-CASH INVESTING TRANSACTIONS:
Accrual for expenditures for operating properties and development properties	148,468	142,133
Assumption of accrued liabilities in connection with acquisitions	3,967	40,624
Tenant improvements funded directly by tenants	10,254	7,211
Initial measurement of operating right of use ground lease assets	83,200		$ 82,938
Initial measurement of operating ground lease liabilities	87,617		87,409
NON-CASH FINANCING TRANSACTIONS:
Accrual of distributions payable to common unitholders	53,205	47,411
Kilroy Realty L.P. [Member]
SUPPLEMENTAL CASH FLOWS INFORMATION:
Cash paid for interest, net of capitalized interest of $58,337 and $46,761 as of September 30, 2019 and 2018, respectively	28,139	32,175
Capitalized interest	58,337	46,761
Cash paid for amounts included in the measurement of ground lease liabilities	3,917	3,598
NON-CASH INVESTING TRANSACTIONS:
Accrual for expenditures for operating properties and development properties	148,468	142,133
Assumption of accrued liabilities in connection with acquisitions	3,967	40,624
Tenant improvements funded directly by tenants	10,254	7,211
Initial measurement of operating right of use ground lease assets	83,200		82,938
Initial measurement of operating ground lease liabilities	87,617		$ 87,409
NON-CASH FINANCING TRANSACTIONS:
Accrual of distributions payable to common unitholders	$ 53,205	$ 47,411

Supplemental Cash Flow Inform_8

Supplemental Cash Flow Information of the Operating Partnership - Reconciliation of Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH:
Cash and cash equivalents	$ 297,620	$ 51,604	$ 86,517	$ 57,649
Restricted cash	6,300	119,430	0	9,149
Cash and cash equivalents and restricted cash	303,920	171,034	86,517	66,798
Kilroy Realty L.P. [Member]
RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH:
Cash and cash equivalents	297,620	51,604	86,517	57,649
Restricted cash	6,300	119,430	0	9,149
Cash and cash equivalents and restricted cash	$ 303,920	$ 171,034	$ 86,517	$ 66,798

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent event [Member] ft² in Thousands, $ in Millions	Oct. 16, 2019USD ($)	Oct. 15, 2019USD ($)ft²abuilding
Subsequent Event [Line Items]
Payment of dividends	$ 53.2
3101-3243 La Cienega Boulevard [Member]
Subsequent Event [Line Items]
Percent leased		1
Rentable square feet | ft²		158
Purchase price		$ 186
Number of Buildings | building		19
Area of land | a		6.9

Uncategorized Items - a93019krc

Label	Element	Value
Accounting Standards Update 2016-02 [Member] | Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (3,146,000)