Kilroy Realty (KRC) 10-Q 29 Jul 21 2021 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2021	Jul. 23, 2021
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
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		116,454,210
Entity Central Index Key	0001025996
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
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	Jun. 30, 2021	Dec. 31, 2020
REAL ESTATE ASSETS (Notes 2 and 3):
Land and improvements	$ 1,551,653	$ 1,628,848
Buildings and improvements	6,682,208	6,783,092
Undeveloped land and construction in progress	2,318,215	1,778,106
Total real estate assets held for investment	10,552,076	10,190,046
Accumulated depreciation and amortization	(1,900,740)	(1,798,646)
Total real estate assets held for investment, net	8,651,336	8,391,400
CASH AND CASH EQUIVALENTS	519,307	731,991
RESTRICTED CASH (Note 3)	450,457	91,139
MARKETABLE SECURITIES (Note 12)	25,885	27,481
CURRENT RECEIVABLES, NET	9,773	12,007
DEFERRED RENT RECEIVABLES, NET	384,475	386,658
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET	184,510	210,949
RIGHT OF USE GROUND LEASE ASSETS (Notes 2 and 11)	141,529	95,523
PREPAID EXPENSES AND OTHER ASSETS, NET (Note 4)	67,494	53,560
TOTAL ASSETS	10,434,766	10,000,708
LIABILITIES:
Secured debt, net (Notes 5 and 12)	251,000	253,582
Unsecured debt, net (Notes 5 and 12)	3,672,152	3,670,099
Accounts payable, accrued expenses and other liabilities	429,168	445,100
Ground lease liabilities (Notes 2 and 11)	143,885	97,778
Accrued dividends and distributions (Note 17)	59,455	59,431
Deferred revenue and acquisition-related intangible liabilities, net	122,902	128,523
Rents received in advance and tenant security deposits	62,739	68,874
Total liabilities	4,741,301	4,723,387
COMMITMENTS AND CONTINGENCIES (Note 11)
Stockholders’ Equity (Note 6):
Common stock, $.01 par value, 280,000,000 shares authorized, 116,454,210 and 116,035,827 shares issued and outstanding, respectively	1,165	1,160
Additional paid-in capital	5,134,320	5,131,916
Retained earnings (distributions in excess of earnings)	311,458	(103,133)
Total stockholders’ equity	5,446,943	5,029,943
Noncontrolling Interests (Notes 1 and 7):
Common units of the Operating Partnership	53,810	49,875
Noncontrolling interests in consolidated property partnerships	192,712	197,503
Total noncontrolling interests	246,522	247,378
Total equity	5,693,465	5,277,321
TOTAL LIABILITIES AND EQUITY (CAPITAL)	10,434,766	10,000,708
Kilroy Realty L.P. [Member]
REAL ESTATE ASSETS (Notes 2 and 3):
Land and improvements	1,551,653	1,628,848
Buildings and improvements	6,682,208	6,783,092
Undeveloped land and construction in progress	2,318,215	1,778,106
Total real estate assets held for investment	10,552,076	10,190,046
Accumulated depreciation and amortization	(1,900,740)	(1,798,646)
Total real estate assets held for investment, net	8,651,336	8,391,400
CASH AND CASH EQUIVALENTS	519,307	731,991
RESTRICTED CASH (Note 3)	450,457	91,139
MARKETABLE SECURITIES (Note 12)	25,885	27,481
CURRENT RECEIVABLES, NET	9,773	12,007
DEFERRED RENT RECEIVABLES, NET	384,475	386,658
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET	184,510	210,949
RIGHT OF USE GROUND LEASE ASSETS (Notes 2 and 11)	141,529	95,523
PREPAID EXPENSES AND OTHER ASSETS, NET (Note 4)	67,494	53,560
TOTAL ASSETS	10,434,766	10,000,708
LIABILITIES:
Secured debt, net (Notes 5 and 12)	251,000	253,582
Unsecured debt, net (Notes 5 and 12)	3,672,152	3,670,099
Accounts payable, accrued expenses and other liabilities	429,168	445,100
Ground lease liabilities (Notes 2 and 11)	143,885	97,778
Accrued dividends and distributions (Note 17)	59,455	59,431
Deferred revenue and acquisition-related intangible liabilities, net	122,902	128,523
Rents received in advance and tenant security deposits	62,739	68,874
Total liabilities	4,741,301	4,723,387
COMMITMENTS AND CONTINGENCIES (Note 11)
Noncontrolling Interests (Notes 1 and 7):
Common units, 116,454,210 and 116,035,827 held by the general partner and 1,150,574 and 1,150,574 held by common limited partners issued and outstanding, respectively (Note 7)	5,500,753	5,079,818
Noncontrolling interests in consolidated property partnerships (Note 1)	192,712	197,503
Total capital	5,693,465	5,277,321
TOTAL LIABILITIES AND EQUITY (CAPITAL)	$ 10,434,766	$ 10,000,708

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	280,000,000	280,000,000
Common stock, shares issued (in shares)	116,454,210	116,035,827
Common stock, shares outstanding (in shares)	116,454,210	116,035,827
Common units [Member] | Kilroy Realty L.P. [Member]
General partner, units issued	116,454,210	116,035,827
General partners, units outstanding	116,454,210	116,035,827
Limited partners, units issued	1,150,574	1,150,574
Limited partners, units outstanding	1,150,574	1,150,574

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue, Product and Service [Extensible List]	us-gaap:ServiceMember	us-gaap:ServiceMember
REVENUES
Rental income (Note 10)	$ 224,473	$ 218,356	$ 459,129	$ 436,989
Other property income	1,510	1,067	2,500	3,762
Total revenues	225,983	219,423	461,629	440,751
EXPENSES
Property expenses	40,482	37,829	79,341	76,812
Real estate taxes	22,109	21,854	47,375	44,056
Ground leases (Note 11)	2,023	2,330	3,851	4,647
General and administrative expenses (Note 9)	24,507	38,597	46,492	57,607
Leasing costs	883	1,330	1,575	2,786
Depreciation and amortization	73,589	80,085	149,521	154,455
Total expenses	163,593	182,025	328,155	340,363
OTHER INCOME (EXPENSES)
Interest income and other net investment gain (loss) (Note 12)	1,337	2,838	2,710	(290)
Interest expense (Note 5)	(21,390)	(15,884)	(43,724)	(30,328)
Gain on sale of depreciable operating property (Note 3)	543	0	457,831	0
Total other (expenses) income	(19,510)	(13,046)	416,817	(30,618)
NET INCOME	42,880	24,352	550,291	69,770
Net income attributable to noncontrolling common units of the Operating Partnership	(354)	(367)	(5,240)	(1,072)
Net income attributable to noncontrolling interests in consolidated property partnerships	(6,687)	(4,367)	(11,581)	(9,263)
Total income attributable to noncontrolling interests	(7,041)	(4,734)	(16,821)	(10,335)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS (UNITHOLDERS)	$ 35,839	$ 19,618	$ 533,470	$ 59,435
Net income available to common stockholders per share – basic (in dollars per share)	$ 0.30	$ 0.17	$ 4.58	$ 0.53
Net income available to common stockholders per share – diluted (in dollars per share)	$ 0.30	$ 0.17	$ 4.56	$ 0.52
Weighted average common shares outstanding – basic (in shares)	116,451,931	115,084,897	116,398,450	110,980,066
Weighted average common shares outstanding – diluted (in shares)	116,917,463	115,539,725	116,859,745	111,464,647
Kilroy Realty L.P. [Member]
Revenue, Product and Service [Extensible List]	us-gaap:ServiceMember	us-gaap:ServiceMember
REVENUES
Rental income (Note 10)	$ 224,473	$ 218,356	$ 459,129	$ 436,989
Other property income	1,510	1,067	2,500	3,762
Total revenues	225,983	219,423	461,629	440,751
EXPENSES
Property expenses	40,482	37,829	79,341	76,812
Real estate taxes	22,109	21,854	47,375	44,056
Ground leases (Note 11)	2,023	2,330	3,851	4,647
General and administrative expenses (Note 9)	24,507	38,597	46,492	57,607
Leasing costs	883	1,330	1,575	2,786
Depreciation and amortization	73,589	80,085	149,521	154,455
Total expenses	163,593	182,025	328,155	340,363
OTHER INCOME (EXPENSES)
Interest income and other net investment gain (loss) (Note 12)	1,337	2,838	2,710	(290)
Interest expense (Note 5)	(21,390)	(15,884)	(43,724)	(30,328)
Gain on sale of depreciable operating property (Note 3)	543	0	457,831	0
Total other (expenses) income	(19,510)	(13,046)	416,817	(30,618)
NET INCOME	42,880	24,352	550,291	69,770
Total income attributable to noncontrolling interests	(6,687)	(4,514)	(11,581)	(9,543)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS (UNITHOLDERS)	$ 36,193	$ 19,838	$ 538,710	$ 60,227
Net income available to common stockholders per share – basic (in dollars per share)	$ 0.30	$ 0.16	$ 4.58	$ 0.52
Net income available to common stockholders per share – diluted (in dollars per share)	$ 0.30	$ 0.16	$ 4.56	$ 0.52
Weighted average common shares outstanding – basic (in shares)	117,602,505	117,098,562	117,549,024	112,997,795
Weighted average common shares outstanding – diluted (in shares)	118,068,037	117,553,390	118,010,319	113,482,376

CONSOLIDATED STATEMENTS OF EQUI

CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Distributions in Excess of Earnings) [Member]	Total Stockholders' Equity [Member]	Noncontrolling Interests [Member]
Beginning balance (in shares) at Dec. 31, 2019		106,016,287
Beginning balance at Dec. 31, 2019	$ 4,570,858	$ 1,060	$ 4,350,917	$ (58,467)	$ 4,293,510	$ 277,348
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	45,418			39,817	39,817	5,601
Issuance of common stock (in shares)		8,897,110
Issuance of common stock	721,794	$ 89	721,705		721,794
Issuance of share-based compensation awards	1,720		1,720		1,720
Non-cash amortization of share-based compensation (Note 9)	8,653		8,653		8,653
Settlement of restricted stock units for shares of common stock (in shares)		269,972
Settlement of restricted stock units for shares of common stock	0	$ 3	(3)
Repurchase of common stock, stock options and restricted stock units (in shares)		(117,445)
Repurchase of common stock, stock options and restricted stock units	(9,799)	$ (1)	(9,798)		(9,799)
Exchange of common units of the Operating Partnership (in shares)		2,000
Exchange of common units of the Operating Partnership	0		81		81	(81)
Distributions to noncontrolling interests in consolidated property partnerships	(2,617)					(2,617)
Adjustment for noncontrolling interest	0		(6,094)		(6,094)	6,094
Dividends declared per common share and common unit	(58,512)			(57,532)	(57,532)	(980)
Ending balance (in shares) at Mar. 31, 2020		115,067,924
Ending balance at Mar. 31, 2020	$ 5,277,515	$ 1,151	5,067,181	(76,182)	4,992,150	285,365
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share and common unit (in dollars per share)	$ 0.485
Beginning balance (in shares) at Dec. 31, 2019		106,016,287
Beginning balance at Dec. 31, 2019	$ 4,570,858	$ 1,060	4,350,917	(58,467)	4,293,510	277,348
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	69,770
Ending balance (in shares) at Jun. 30, 2020		115,176,538
Ending balance at Jun. 30, 2020	5,253,589	$ 1,152	5,084,362	(113,223)	4,972,291	281,298
Beginning balance (in shares) at Mar. 31, 2020		115,067,924
Beginning balance at Mar. 31, 2020	5,277,515	$ 1,151	5,067,181	(76,182)	4,992,150	285,365
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	24,352			19,618	19,618	4,734
Issuance of common stock	(45)		(45)		(45)
Issuance of share-based compensation awards	805		805		805
Non-cash amortization of share-based compensation (Note 9)	13,576		13,576		13,576
Settlement of restricted stock units for shares of common stock (in shares)		33,581
Settlement of restricted stock units for shares of common stock	0
Repurchase of common stock, stock options and restricted stock units (in shares)		(11,668)
Repurchase of common stock, stock options and restricted stock units	(735)		(735)		(735)
Exchange of common units of the Operating Partnership (in shares)		86,701
Exchange of common units of the Operating Partnership	0	$ 1	3,761		3,762	(3,762)
Distributions to noncontrolling interests in consolidated property partnerships	(4,281)					(4,281)
Adjustment for noncontrolling interest	0		(181)		(181)	181
Dividends declared per common share and common unit	(57,598)			(56,659)	(56,659)	(939)
Ending balance (in shares) at Jun. 30, 2020		115,176,538
Ending balance at Jun. 30, 2020	$ 5,253,589	$ 1,152	5,084,362	(113,223)	4,972,291	281,298
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share and common unit (in dollars per share)	$ 0.485
Beginning balance (in shares) at Dec. 31, 2020	116,035,827	116,035,827
Beginning balance at Dec. 31, 2020	$ 5,277,321	$ 1,160	5,131,916	(103,133)	5,029,943	247,378
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	507,411			497,631	497,631	9,780
Issuance of share-based compensation awards	1,950		1,950		1,950
Non-cash amortization of share-based compensation (Note 9)	9,604		9,604		9,604
Settlement of restricted stock units for shares of common stock (in shares)		769,701
Settlement of restricted stock units for shares of common stock	0	$ 8	(8)
Repurchase of common stock, stock options and restricted stock units (in shares)		(355,158)
Repurchase of common stock, stock options and restricted stock units	(21,137)	$ (3)	(21,134)		(21,137)
Distributions to noncontrolling interests in consolidated property partnerships	(11,680)					(11,680)
Adjustment for noncontrolling interest	0		256		256	(256)
Dividends declared per common share and common unit	(60,577)			(60,002)	(60,002)	(575)
Ending balance (in shares) at Mar. 31, 2021		116,450,370
Ending balance at Mar. 31, 2021	$ 5,702,892	$ 1,165	5,122,584	334,496	5,458,245	244,647
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share and common unit (in dollars per share)	$ 0.500
Beginning balance (in shares) at Dec. 31, 2020	116,035,827	116,035,827
Beginning balance at Dec. 31, 2020	$ 5,277,321	$ 1,160	5,131,916	(103,133)	5,029,943	247,378
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 550,291
Ending balance (in shares) at Jun. 30, 2021	116,454,210	116,454,210
Ending balance at Jun. 30, 2021	$ 5,693,465	$ 1,165	5,134,320	311,458	5,446,943	246,522
Beginning balance (in shares) at Mar. 31, 2021		116,450,370
Beginning balance at Mar. 31, 2021	5,702,892	$ 1,165	5,122,584	334,496	5,458,245	244,647
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	42,880			35,839	35,839	7,041
Issuance of share-based compensation awards	645		645		645
Non-cash amortization of share-based compensation (Note 9)	11,193		11,193		11,193
Settlement of restricted stock units for shares of common stock (in shares)		3,840
Settlement of restricted stock units for shares of common stock	0
Distributions to noncontrolling interests in consolidated property partnerships	(4,692)					(4,692)
Adjustment for noncontrolling interest	0		(102)		(102)	102
Dividends declared per common share and common unit	$ (59,453)			(58,877)	(58,877)	(576)
Ending balance (in shares) at Jun. 30, 2021	116,454,210	116,454,210
Ending balance at Jun. 30, 2021	$ 5,693,465	$ 1,165	$ 5,134,320	$ 311,458	$ 5,446,943	$ 246,522
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per common share and common unit (in dollars per share)	$ 0.500

CONSOLIDATED STATEMENTS OF EQ_2

CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020
Statement of Stockholders' Equity [Abstract]
Dividends declared per common share and common unit (in dollars per share)	$ 0.500	$ 0.500	$ 0.485	$ 0.485

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 550,291	$ 69,770
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of real estate assets and leasing costs	146,468	148,419
Depreciation of non-real estate furniture, fixtures and equipment	3,053	6,036
Revenue reversals for doubtful accounts, net (Note 10)	746	12,381
Non-cash amortization of share-based compensation awards	17,415	18,311
Non-cash amortization of deferred financing costs and debt discounts	1,590	1,076
Non-cash amortization of net below market rents	(2,194)	(4,500)
Gain on sale of depreciable operating property (Note 3)	(457,831)	0
Non-cash amortization of deferred revenue related to tenant-funded tenant improvements	(8,915)	(8,793)
Straight-line rents	(31,029)	(33,514)
Amortization of right of use ground lease assets	424	408
Net change in other operating assets	(3,622)	13,991
Net change in other operating liabilities	70	437
Net cash provided by operating activities	216,466	224,022
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for development properties and undeveloped land	(263,227)	(293,711)
Expenditures for operating properties and other capital assets	(63,903)	(80,630)
Expenditures for acquisition of development properties and undeveloped land (Note 2)	(586,927)	0
Net proceeds received from dispositions (Note 3)	1,013,359	0
Net increase in acquisition-related deposits	(4,000)	0
Net cash provided by (used in) investing activities	95,302	(374,341)
CASH FLOWS FROM FINANCING ACTIVITIES:
Principal payments and repayments of secured debt	(2,645)	(2,543)
Financing costs (Note 5)	(7,569)	(2,283)
Repurchase of common stock and restricted stock units	(21,137)	(10,534)
Distributions to noncontrolling interests in consolidated property partnerships	(16,389)	(6,915)
Dividends and distributions paid to common stockholders and common unitholders	(117,394)	(109,187)
Net proceeds from issuance of common stock	0	721,749
Proceeds from the issuance of unsecured debt (Note 5)	0	350,000
Borrowings on unsecured revolving credit facility	0	190,000
Repayments on unsecured revolving credit facility	0	(435,000)
Net cash (used in) provided by financing activities	(165,134)	695,287
Net increase in cash and cash equivalents and restricted cash	146,634	544,968
Cash and cash equivalents and restricted cash, beginning of period	823,130	76,344
Cash and cash equivalents and restricted cash, end of period	969,764	621,312
Kilroy Realty L.P. [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	550,291	69,770
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of real estate assets and leasing costs	146,468	148,419
Depreciation of non-real estate furniture, fixtures and equipment	3,053	6,036
Revenue reversals for doubtful accounts, net (Note 10)	746	12,381
Non-cash amortization of share-based compensation awards	17,415	18,311
Non-cash amortization of deferred financing costs and debt discounts	1,590	1,076
Non-cash amortization of net below market rents	(2,194)	(4,500)
Gain on sale of depreciable operating property (Note 3)	(457,831)	0
Non-cash amortization of deferred revenue related to tenant-funded tenant improvements	(8,915)	(8,793)
Straight-line rents	(31,029)	(33,514)
Amortization of right of use ground lease assets	424	408
Net change in other operating assets	(3,622)	13,991
Net change in other operating liabilities	70	437
Net cash provided by operating activities	216,466	224,022
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for development properties and undeveloped land	(263,227)	(293,711)
Expenditures for operating properties and other capital assets	(63,903)	(80,630)
Expenditures for acquisition of development properties and undeveloped land (Note 2)	(586,927)	0
Net proceeds received from dispositions (Note 3)	1,013,359	0
Net increase in acquisition-related deposits	(4,000)	0
Net cash provided by (used in) investing activities	95,302	(374,341)
CASH FLOWS FROM FINANCING ACTIVITIES:
Principal payments and repayments of secured debt	(2,645)	(2,543)
Financing costs (Note 5)	(7,569)	(2,283)
Repurchase of common stock and restricted stock units	(21,137)	(10,534)
Distributions to noncontrolling interests in consolidated property partnerships	(16,389)	(6,915)
Dividends and distributions paid to common stockholders and common unitholders	(117,394)	(109,187)
Net proceeds from issuance of common stock	0	721,749
Proceeds from the issuance of unsecured debt (Note 5)	0	350,000
Borrowings on unsecured revolving credit facility	0	190,000
Repayments on unsecured revolving credit facility	0	(435,000)
Net cash (used in) provided by financing activities	(165,134)	695,287
Net increase in cash and cash equivalents and restricted cash	146,634	544,968
Cash and cash equivalents and restricted cash, beginning of period	823,130	76,344
Cash and cash equivalents and restricted cash, end of period	$ 969,764	$ 621,312

CONSOLIDATED STATEMENTS OF CAPI

CONSOLIDATED STATEMENTS OF CAPITAL (KILROY REALTY, L.P.) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	$ 42,880	$ 507,411	$ 24,352	$ 45,418	$ 550,291	$ 69,770
Non-cash amortization of share-based compensation (Note 9)	11,193	9,604	13,576	8,653
Settlement of restricted stock units	0	0	0	0
Distributions to noncontrolling interests in consolidated property partnerships	(4,692)	(11,680)	(4,281)	(2,617)
Kilroy Realty L.P. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	5,702,892	5,277,321	5,277,515	4,570,858	5,277,321	4,570,858
Net income	42,880	507,411	24,352	45,418	550,291	69,770
Issuance of common units			(45)	721,794
Issuance of share-based compensation awards	645	1,950	805	1,720
Non-cash amortization of share-based compensation (Note 9)	11,193	9,604	13,576	8,653
Settlement of restricted stock units	0	0	0	0
Repurchase of common units, stock options and restricted stock units		(21,137)	(735)	(9,799)
Distributions to noncontrolling interests in consolidated property partnerships	(4,692)	(11,680)	(4,281)	(2,617)
Distributions declared per common unit	(59,453)	(60,577)	(57,598)	(58,512)
Ending balance	$ 5,693,465	$ 5,702,892	$ 5,253,589	$ 5,277,515	$ 5,693,465	$ 5,253,589
Partners' Capital [Member] | Kilroy Realty L.P. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)	117,600,944	117,186,401	117,089,211	108,039,574	117,186,401	108,039,574
Beginning balance	$ 5,512,175	$ 5,079,818	$ 5,074,003	$ 4,369,758	$ 5,079,818	$ 4,369,758
Net income	36,193	502,517	$ 19,838	$ 40,389
Issuance of common units (in units)			0	8,897,110
Issuance of common units			$ (45)	$ 721,794
Issuance of share-based compensation awards	645	1,950	805	1,720
Non-cash amortization of share-based compensation (Note 9)	$ 11,193	$ 9,604	$ 13,576	$ 8,653
Settlement of restricted stock units (in units)	3,840	769,701	33,581	269,972
Repurchase of common units, stock options and restricted stock units (in units)		(355,158)	(11,668)	(117,445)
Repurchase of common units, stock options and restricted stock units		$ (21,137)	$ (735)	$ (9,799)
Distributions declared per common unit	$ (59,453)	$ (60,577)	$ (57,598)	$ (58,512)
Ending balance (in units)	117,604,784	117,600,944	117,111,124	117,089,211	117,604,784	117,111,124
Ending balance	$ 5,500,753	$ 5,512,175	$ 5,049,844	$ 5,074,003	$ 5,500,753	$ 5,049,844
Noncontrolling Interests [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	7,041	9,780	4,734	5,601
Distributions to noncontrolling interests in consolidated property partnerships	(4,692)	(11,680)	(4,281)	(2,617)
Noncontrolling Interests [Member] | Kilroy Realty L.P. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	190,717	197,503	203,512	201,100	197,503	201,100
Net income	6,687	4,894	4,514	5,029
Distributions to noncontrolling interests in consolidated property partnerships	(4,692)	(11,680)	(4,281)	(2,617)
Ending balance	$ 192,712	$ 190,717	$ 203,745	$ 203,512	$ 192,712	$ 203,745

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CAPITAL (KILROY REALTY, L.P.) (Parenthetical) - $ / shares	3 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020
Kilroy Realty L.P. [Member]
Dividends declared per common unit (in dollars per unit)	$ 0.500	$ 0.500	$ 0.485	$ 0.485

Organization, Ownership and Bas

Organization, Ownership and Basis of Presentation	6 Months Ended
	Jun. 30, 2021
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 in the United States. We own, develop, acquire and manage real estate assets, consisting primarily of Class A properties in Greater Los Angeles, San Diego County, the San Francisco Bay Area, the Pacific Northwest and Austin, Texas, 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”). 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 June 30, 2021: Number of Rentable Number of Percentage Occupied (1) Percentage Leased Stabilized Office Properties (2) 118 14,151,674 427 91.8 % 93.6 % ________________________ (1) Represents physical and economic occupancy. (2) Includes stabilized life science and retail space. Number of Number of 2021 Average Occupancy Stabilized Residential Properties 3 1,001 70.6 % 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 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 life science 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 or phases of projects are placed in service. During the six months ended June 30, 2021, we added three development projects to our stabilized portfolio consisting of two buildings totaling 252,486 square feet of office space in San Diego, California and 193 residential units in Hollywood, California. As of June 30, 2021, the following properties were excluded from our stabilized portfolio. We did not have any redevelopment properties or properties held for sale at June 30, 2021. Number of Estimated Rentable Square Feet (1) In-process development projects - tenant improvement (2) 4 2,220,000 In-process development projects - under construction 2 1,110,000 ________________________ (1) Estimated rentable square feet upon completion. (2) Includes the development property acquired in Austin, Texas during the three months ended June 30, 2021. Refer to Note 2 “Acquisitions” for additional information. Our stabilized portfolio also excludes our future development pipeline, which as of June 30, 2021 was comprised of six future development sites, representing approximately 59 gross acres of undeveloped land. As of June 30, 2021, 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 stabilized office properties, one development project in the tenant improvement phase and one future development project located in the state of Washington, and one recently acquired development project in the tenant improvement phase located in Austin, Texas. All of our properties and development projects are 100% owned, excluding four office properties owned by three consolidated property partnerships. Two of the three consolidated 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 June 30, 2021, the Company owned a 56% common equity interest in both 100 First LLC and 303 Second LLC. The third consolidated property partnership, Redwood City Partners, LLC (“Redwood LLC”) owned two office properties in Redwood City, California. As of June 30, 2021, 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, 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, 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 June 30, 2021, the Company owned an approximate 99.0% common general partnership interest in the Operating Partnership. The remaining approximate 1.0% common limited partnership interest in the Operating Partnership as of June 30, 2021 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”. 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, 2021. 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, 2020. 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 June 30, 2021, the consolidated financial statements of the Company included three VIEs in addition to the Operating Partnership: two of the consolidated property partnerships, 100 First LLC, 303 Second LLC and one entity established during the second quarter of 2021 to facilitate potential future Section 1031 Exchanges. At June 30, 2021, the Company and the Operating Partnership were determined to be the primary beneficiaries of these three VIEs since we had the ability to control the activities that most significantly impact each of the VIEs’ economic performance. As of June 30, 2021, the three VIEs’ total assets, liabilities and noncontrolling interests included on our consolidated balance sheet were approximately $461.7 million (of which $393.6 million related to real estate held for investment), approximately $28.1 million and approximately $187.2 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, 2020, the consolidated financial statements of the Company included two VIEs in addition to the Operating Partnership: 100 First LLC and 303 Second LLC. At December 31, 2020, the Company and the Operating Partnership were determined to be the primary beneficiaries of these two VIEs since we had the ability to control the activities that most significantly impact each of the VIEs’ economic performance. At December 31, 2020, the impact of consolidating the VIEs increased the Company’s total assets, liabilities and noncontrolling interests on our consolidated balance sheet by approximately $469.3 million (of which $394.6 million related to real estate held for investment), approximately $33.9 million and approximately $191.9 million, respectively.

Acquisitions

Acquisitions	6 Months Ended
	Jun. 30, 2021
Asset Acquisition [Abstract]
Acquisitions	Acquisitions Development Property Acquisitions During the six months ended June 30, 2021, we acquired the following development properties in two transactions from unrelated third parties. The acquisitions were funded with the proceeds from the operating property disposition completed during the three months ended March 31, 2021 that were temporarily being held by a qualified intermediary, at our discretion, for the purpose of facilitating a Section 1031 Exchange. Property Date of Acquisition Submarket Purchase Price (in millions) (1) 2045 Pacific Highway, San Diego, CA (2) June 22, 2021 Little Italy $ 42.0 200 W. 6th Street, Austin, TX (3) June 23, 2021 Austin CBD 580.2 Total $ 622.2 ________________________ (1) Excludes acquisition-related costs. (2) This property was added to our future development pipeline. In connection with this acquisition, we also recorded $5.2 million of environmental remediation liabilities as of the date of acquisition, which is not included in the purchase price above.

Dispositions

Dispositions	6 Months Ended
	Jun. 30, 2021
Discontinued Operations and Disposal Groups [Abstract]
Dispositions	Dispositions Operating Property Dispositions The following table summarizes the one operating property sold during the six months ended June 30, 2021: Property Month of Disposition Number of Buildings Rentable Square Feet Sales Price (in billions) (1) 1800 Owens Street, San Francisco, CA (The Exchange on 16th) March 1 750,370 $ 1.08 ___________________________ (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 six months ended June 30, 2021 was $457.8 million, including $0.5 million recognized during the three months ended June 30, 2021 related to trailing post-closing items. Restricted Cash Related to Dispositions

Prepaid Expenses and Other Asse

Prepaid Expenses and Other Assets, Net	6 Months Ended
	Jun. 30, 2021
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 June 30, 2021 and December 31, 2020: June 30, 2021 December 31, 2020 (in thousands) Furniture, fixtures and other long-lived assets, net $ 40,679 $ 43,367 Prepaid expenses, acquisition deposits and other assets, net (1) 26,815 10,193 Total prepaid expenses and other assets, net $ 67,494 $ 53,560 ___________________________ (1) Includes $5.0 million of non-refundable acquisition deposits related to an acquisition which closed on July 8, 2021. Refer to Note 17 “Subsequent Events” for additional information.

Secured and Unsecured Debt of t

Secured and Unsecured Debt of the Operating Partnership	6 Months Ended
	Jun. 30, 2021
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 The Company generally guarantees all of the Operating Partnership’s unsecured debt obligations including the unsecured revolving credit facility and all of the unsecured senior notes. Unsecured Revolving Credit Facility In April 2021, the Operating Partnership amended and restated the terms of its unsecured revolving credit facility. The amendment and restatement increased the size of the unsecured revolving credit facility from $750.0 million to $1.1 billion, reduced the borrowing costs, extended the maturity date of the unsecured revolving credit facility to July 2025, with two six-month extension options, and added a sustainability-linked pricing component whereby the interest rate is lowered by 0.01% if certain sustainability performance targets are met. The LIBOR replacement provisions of the unsecured revolving credit facility permit the use of rates based on the secured overnight financing rate (“SOFR”) administered by the Federal Reserve Bank of New York. The following table summarizes the balance and terms of our unsecured revolving credit facility as of June 30, 2021 and December 31, 2020: June 30, 2021 December 31, 2020 (in thousands) Outstanding borrowings $ — $ — Remaining borrowing capacity 1,100,000 750,000 Total borrowing capacity (1) $ 1,100,000 $ 750,000 Interest rate (2) 1.00 % 1.14 % Facility fee-annual rate (3) 0.200% Maturity date July 2025 July 2022 ________________________ (1) We may elect to borrow, subject to bank approval and obtaining commitments for any additional borrowing capacity, up to an additional $500.0 million and $600.0 million as of June 30, 2021 and December 31, 2020, respectively, under an accordion feature under the terms of the unsecured revolving credit facility. (2) Our unsecured revolving credit facility interest rate was calculated based on the contractual rate of LIBOR plus 0.900% and LIBOR plus 1.000% as of June 30, 2021 and December 31, 2020, respectively. (3) Our facility fee is paid on a quarterly basis and is calculated based on the total borrowing capacity. In addition to the facility fee, we incurred debt origination and legal costs. As of June 30, 2021 and December 31, 2020, $8.3 million and $2.1 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 respective maturity dates presented 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 and to supplement cash balances given uncertainties and volatility in market conditions. Debt Covenants and Restrictions The unsecured revolving credit facility, the unsecured senior notes, the Series A and B Notes due 2026, Series A and B Notes due 2027 and 2029, Notes due 2031 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 June 30, 2021. Debt Maturities The following table summarizes the stated debt maturities and scheduled amortization payments as of June 30, 2021: Year (in thousands) Remaining 2021 $ 2,698 2022 5,554 2023 305,775 2024 431,006 2025 406,246 2026 401,316 Thereafter 2,399,125 Total aggregate principal value (1) $ 3,951,720 ________________________ (1) Includes gross principal balance of outstanding debt before the effect of the following at June 30, 2021: $20.8 million of unamortized deferred financing costs for the unsecured senior notes and secured debt and $7.7 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 and deferred financing cost amortization, net of capitalized interest, for the three and six months ended June 30, 2021 and 2020. 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 June 30, Six Months Ended June 30, 2021 2020 2021 2020 (in thousands) Gross interest expense $ 39,463 $ 36,400 $ 78,705 $ 72,262 Capitalized interest and deferred financing costs (18,073) (20,516) (34,981) (41,934) Interest expense $ 21,390 $ 15,884 $ 43,724 $ 30,328

Stockholders' Equity of the Com

Stockholders' Equity of the Company	6 Months Ended
	Jun. 30, 2021
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 our 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. The Company did not have any outstanding forward equity sale agreements to be settled at June 30, 2021. Since commencement of our current at-the-market program, we have completed sales of 3,594,576 shares of common stock through June 30, 2021. As of June 30, 2021, we may offer and sell shares of our common stock having an aggregate gross sales price up to approximately $214.2 million under our current at-the-market program. The Company did not complete any sales of common stock under the program during the six months ended June 30, 2021.

Noncontrolling Interests on the

Noncontrolling Interests on the Company's Consolidated Financial Statements	6 Months Ended
	Jun. 30, 2021
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 99.0%, 99.0%, and 98.3% common general partnership interest in the Operating Partnership as of June 30, 2021, December 31, 2020 and June 30, 2020, respectively. The remaining approximate 1.0%, 1.0%, and 1.7% common limited partnership interest as of June 30, 2021, December 31, 2020 and June 30, 2020, respectively, was owned by non-affiliated investors and certain of our executive officers and directors in the form of noncontrolling common units. There were 1,150,574, 1,150,574 and 1,934,586 common units outstanding held by these investors, executive officers and directors as of June 30, 2021, December 31, 2020 and June 30, 2020, 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 $81.7 million

Partners' Capital of the Operat

Partners' Capital of the Operating Partnership	6 Months Ended
	Jun. 30, 2021
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: June 30, 2021 December 31, 2020 June 30, 2020 Company owned common units in the Operating Partnership 116,454,210 116,035,827 115,176,538 Company owned general partnership interest 99.0 % 99.0 % 98.3 % Noncontrolling common units of the Operating Partnership 1,150,574 1,150,574 1,934,586 Ownership interest of noncontrolling interest 1.0 % 1.0 % 1.7 % For further discussion of the noncontrolling common units as of June 30, 2021 and December 31, 2020, refer to Note 7 “Noncontrolling Interests on the Company’s Consolidated Financial Statements.”

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2021
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation Stockholder Approved Share-Based Incentive Compensation Plan As of June 30, 2021, 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 10.7 million shares of our common stock for possible issuance under our 2006 Plan. As of June 30, 2021, approximately 1.4 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 other performance and market conditions (as defined below) for awards still in a performance period. 2021 Share-Based Compensation Grants In January and February 2021, the Executive Compensation Committee of the Company’s Board of Directors awarded 332,707 restricted stock units (“RSUs”) to certain officers of the Company under the 2006 Plan, which included 172,430 RSUs (at the target level of performance) that are subject to market and/or performance-based vesting requirements (the “2021 Performance-Based RSUs”) and 160,277 RSUs that are subject to time-based vesting requirements (the “2021 Time-Based RSUs”). 2021 Performance-Based RSU Grant The 2021 Performance-Based RSUs are scheduled to vest at the end of a three year period (consisting of calendar years 2021-2023). A target number of 2021 Performance-Based RSUs were awarded, and the final number of 2021 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, 2021 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 2021 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 2021 Performance-Based RSUs ultimately earned could fluctuate from the target number of 2021 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 2021 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. During the six months ended June 30, 2021, we recognized $2.8 million of compensation expense for the 2021 Performance-Based RSU grant. In the event we achieve a lower level of performance or fail to meet the FFO performance condition, we would reverse a portion or all of the $2.8 million of compensation expense. Compensation expense for the 2021 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 vesting period, except for one participant whose compensation expense is recognized on a rolling twelve-month basis. Each 2021 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 2021 Performance-Based RSU grants covered by the debt to EBITDA ratio performance condition was based on the $57.85 share price on the February 18, 2021 grant date. The determination of the grant date fair value of the portion of the 2021 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 the following grant date fair value per share. Fair Value Assumptions Valuation date February 18, 2021 Expected share price volatility 35.0% Risk-free interest rate 0.20% Fair value per share on valuation date (1) $63.93 ________________________ (1) Using the same Monte Carlo methodology and assumptions, the grant date fair value of one participant’s 2021 Performance-Based RSU grants was calculated as $66.95 per share. The computation of expected volatility is based on a blend of the historical volatility of our shares of common stock over approximately 2.9 years, as that is expected to be most consistent with future volatility and equates to 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 18, 2021. The total grant date fair value of the 2021 Performance-Based RSU awards was $10.6 million on the February 18, 2021 grant date of the awards. For the three and six months ended June 30, 2021, 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. 2021 Time-Based RSU Grant The 2021 Time-Based RSUs are scheduled to vest in three equal annual installments beginning on January 5, 2022 through January 5, 2024. Compensation expense for the 2021 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, except for one participant whose compensation expense is recognized on a rolling twelve-month basis. Each 2021 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 2021 Time-Based RSU awards was $9.1 million, which was based on the $56.63 and $57.85 closing share prices of the Company’s common stock on the NYSE on the January 29, 2021 and February 18, 2021 grant dates, respectively. 2020 and 2019 Performance-Based RSUs Compensation cost for the 2020 performance-based RSUs for the three and six months ended June 30, 2021 assumes the 2020 debt to EBITDA ratio performance condition is met at 150% of the target level of achievement (175.0% for one participant). Compensation cost for the 2019 performance-based RSUs for the three and six months ended June 30, 2021 assumes the 2019 debt to EBITDA ratio performance condition is met at the maximum level of achievement. Share-Based Compensation Cost Recorded During the Period The total compensation cost for all share-based compensation programs was $11.2 million and $13.6 million for the three months ended June 30, 2021 and 2020, respectively, and $20.8 million and $22.2 million for the six months ended June 30, 2021 and 2020, respectively. Share-based compensation costs for the three and six months ended June 30, 2020 include $4.1 million and $4.3 million, respectively, of accelerated share-based compensation costs related to severance packages, including for an executive officer departure. Of the total share-based compensation costs, $1.7 million and $3.4 million was capitalized as part of real estate assets for the three and six months ended June 30, 2021 and $2.0 million and $3.9 million was capitalized as part of the real estate assets for the three and six months ended June 30, 2020, respectively. As of June 30, 2021, there was approximately $41.8 million of total unrecognized compensation cost related to nonvested incentive awards granted under share-based compensation arrangements that is expected to be recognized over a weighted-average period of 1.5 years. The remaining compensation cost related to these nonvested incentive awards had been recognized in periods prior to June 30, 2021.

Rental Income and Future Minimu

Rental Income and Future Minimum Rent	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Rental Income and Future Minimum Rent	Rental Income and Future Minimum Rent Our rental income is primarily comprised of payments defined under leases and are either subject to scheduled fixed increases or adjustments in rent based on the Consumer Price Index. 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 and collectability reversals for the three and six months ended June 30, 2021 and 2020: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 (in thousands) Fixed lease payments $ 197,846 $ 194,486 $ 402,062 $ 387,961 Variable lease payments 26,339 29,764 57,814 61,409 Net collectability recoveries (reversals) (1) 288 (5,894) (747) (12,381) Total rental income $ 224,473 $ 218,356 $ 459,129 $ 436,989 _____________________ (1) Represents adjustments to rental income related to our assessment of the collectability of amounts due under leases with our tenants. For the three and six months ended June 30, 2020, includes a reduction in revenue of $5.9 million and $12.4 million, respectively, primarily as a result of the COVID-19 pandemic. We have operating leases with tenants that expire at various dates through 2044. Generally, the leases grant tenants renewal options. Future contractual minimum rent under operating leases, which includes amounts contractually due from leases that are on a cash basis of reporting due to creditworthiness considerations, as of June 30, 2021 for future periods is summarized as follows: Year Ending (in thousands) Remaining 2021 $ 352,227 2022 782,849 2023 768,461 2024 728,204 2025 690,384 2026 635,807 Thereafter 2,509,266 Total (1) $ 6,467,198 _____________________ (1) Excludes residential leases and leases with a term of one year or less.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies General As of June 30, 2021, we had commitments of approximately $1.0 billion, excluding our ground lease commitments, for contracts and executed leases directly related to our operating and development properties. Ground Leases The following table summarizes our properties that are held subject to long-term noncancellable ground lease obligations as of June 30, 2021 and the respective contractual expiration dates: Property Contractual Expiration Date (1) 601 108th Ave NE, Bellevue, WA (2) November 2093 701, 801 and 837 N. 34th Street, Seattle, WA (3) 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 3243 S. La Cienega Boulevard, Los Angeles, CA October 2106 200 W. 6th St. Austin, TX (4) December 2112 ____________________ (1) Reflects the contractual expiration date prior to the impact of any extension or purchase options held by the Company. (2) In July 2021, we completed the acquisition of the land subject to this ground lease. Refer to Note 17 “Subsequent Events” for additional information. (3) 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 extension options are not assumed to be exercised in our calculation of the present value of the future minimum lease payments for this lease. (4) We entered into this ground lease in connection with a development property acquisition in June 2021. Refer to Note 2 “Acquisitions” for additional information. To determine the discount rates used to calculate the present value of the minimum future lease payments for our ground leases, we used a hypothetical curve derived from unsecured corporate borrowing rates over the lease term. The weighted average discount rate used to determine the present value of our minimum lease payments was 4.74%. As of June 30, 2021, the weighted average remaining lease term of our ground leases is 66 years. For the three months ended June 30, 2021 and 2020, variable lease costs totaling $0.6 million and $0.9 million, respectively, were recorded to ground lease expense on our consolidated statements of operations. For the six months ended June 30, 2021 and 2020, variable lease costs totaling $0.9 million and $1.7 million, respectively, were recorded to ground lease expense on our consolidated statements of operations. The minimum commitment under our ground leases as of June 30, 2021 for future periods is summarized as follows: Year Ending (in thousands) Remaining 2021 $ 3,699 2022 7,435 2023 7,489 2024 7,525 2025 7,561 2026 7,597 Thereafter 440,411 Total undiscounted cash flows (1)(2)(3)(4)(5)(6)(7) 481,717 Present value discount (337,832) Ground lease liabilities $ 143,885 ________________________ (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 June 30, 2021. (3) One of our ground lease obligations includes a component that 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 June 30, 2021 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 June 30, 2021 for the remainder of the lease term since we cannot predict future adjustments. (5) One of our ground lease obligations includes a component that 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 June 30, 2021 for the remainder of the lease term since we cannot predict future adjustments. (6) One of our ground lease obligations is subject to fixed 5% ground rent increases every five years, with the next increase occurring on December 1, 2022. (7) One of our ground lease obligations is subject to fixed 2% ground rent increases every year, with ground rent resets occurring every ten years based on CPI. The contractual obligations for that lease included above assume increases for the remaining current ten-year period based on the current annual ground lease obligation in effect at June 30, 2021 and no subsequent changes for the remainder of the lease term since we cannot predict future CPI 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 June 30, 2021, we had accrued environmental remediation liabilities of approximately $77.6 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 June 30, 2021 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	6 Months Ended
	Jun. 30, 2021
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 June 30, 2021 and December 31, 2020: Fair Value (Level 1) (1) June 30, 2021 December 31, 2020 Description (in thousands) Marketable securities (2) $ 25,885 $ 27,481 ________________________ (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 included in general and administrative expenses on our consolidated statements of operations for the period. The following table sets forth the net gain (loss) on marketable securities recorded during the three and six months ended June 30, 2021 and 2020: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Description (in thousands) (in thousands) Net gain (loss) on marketable securities $ 1,261 $ 2,662 $ 2,565 $ (564) 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 June 30, 2021 and December 31, 2020: June 30, 2021 December 31, 2020 Carrying Fair (1) Carrying Fair (1) (in thousands) Liabilities Secured debt, net $ 251,000 $ 278,882 $ 253,582 $ 282,559 Unsecured debt, net $ 3,672,152 $ 4,014,791 $ 3,670,099 $ 4,089,339 ________________________ (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	6 Months Ended
	Jun. 30, 2021
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 six months ended June 30, 2021 and 2020: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 (in thousands, except share and per share amounts) Numerator: Net income available to common stockholders $ 35,839 $ 19,618 $ 533,470 $ 59,435 Allocation to participating securities (1) (371) (542) (736) (1,085) Numerator for basic and diluted net income available to common stockholders $ 35,468 $ 19,076 $ 532,734 $ 58,350 Denominator: Basic weighted average vested shares outstanding 116,451,931 115,084,897 116,398,450 110,980,066 Effect of dilutive securities 465,532 454,828 461,295 484,581 Diluted weighted average vested shares and common stock equivalents outstanding 116,917,463 115,539,725 116,859,745 111,464,647 Basic earnings per share: Net income available to common stockholders per share $ 0.30 $ 0.17 $ 4.58 $ 0.53 Diluted earnings per share: Net income available to common stockholders per share $ 0.30 $ 0.17 $ 4.56 $ 0.52 ________________________ (1) Participating securities include certain time-based RSUs and vested market measure-based RSUs. Share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are considered participating securities. The impact of potentially dilutive common shares, including stock options, RSUs and other securities are considered in our diluted earnings per share calculation for the three and six months ended June 30, 2021 and 2020. Certain market measure-based RSUs are not included in dilutive securities for the three and six months ended June 30, 2021 and 2020, 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	6 Months Ended
	Jun. 30, 2021
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 six months ended June 30, 2021 and 2020: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 (in thousands, except share and per share amounts) Numerator: Net income available to common stockholders $ 35,839 $ 19,618 $ 533,470 $ 59,435 Allocation to participating securities (1) (371) (542) (736) (1,085) Numerator for basic and diluted net income available to common stockholders $ 35,468 $ 19,076 $ 532,734 $ 58,350 Denominator: Basic weighted average vested shares outstanding 116,451,931 115,084,897 116,398,450 110,980,066 Effect of dilutive securities 465,532 454,828 461,295 484,581 Diluted weighted average vested shares and common stock equivalents outstanding 116,917,463 115,539,725 116,859,745 111,464,647 Basic earnings per share: Net income available to common stockholders per share $ 0.30 $ 0.17 $ 4.58 $ 0.53 Diluted earnings per share: Net income available to common stockholders per share $ 0.30 $ 0.17 $ 4.56 $ 0.52 ________________________ (1) Participating securities include certain time-based RSUs and vested market measure-based RSUs. Share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are considered participating securities. The impact of potentially dilutive common shares, including stock options, RSUs and other securities are considered in our diluted earnings per share calculation for the three and six months ended June 30, 2021 and 2020. Certain market measure-based RSUs are not included in dilutive securities for the three and six months ended June 30, 2021 and 2020, 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 six months ended June 30, 2021 and 2020: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 (in thousands, except unit and per unit amounts) Numerator: Net income available to common unitholders $ 36,193 $ 19,838 $ 538,710 $ 60,227 Allocation to participating securities (1) (371) (542) (736) (1,085) Numerator for basic and diluted net income available to common unitholders $ 35,822 $ 19,296 $ 537,974 $ 59,142 Denominator: Basic weighted average vested units outstanding 117,602,505 117,098,562 117,549,024 112,997,795 Effect of dilutive securities 465,532 454,828 461,295 484,581 Diluted weighted average vested units and common unit equivalents outstanding 118,068,037 117,553,390 118,010,319 113,482,376 Basic earnings per unit: Net income available to common unitholders per unit $ 0.30 $ 0.16 $ 4.58 $ 0.52 Diluted earnings per unit: Net income available to common unitholders per unit $ 0.30 $ 0.16 $ 4.56 $ 0.52 ________________________ (1) Participating securities include certain time-based RSUs and vested market measure-based RSUs. Share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are considered participating securities. The impact of potentially dilutive common units, including stock options, RSUs and other securities are considered in our diluted earnings per share calculation for the three and six months ended June 30, 2021 and 2020. Certain market measure-based RSUs are not included in dilutive securities for the three and six months ended June 30, 2021 and 2020, 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	6 Months Ended
	Jun. 30, 2021
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information of the Company	Supplemental Cash Flow Information of the Company Supplemental cash flow information follows (in thousands): Six Months Ended June 30, 2021 2020 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $33,244 and $39,952 as of June 30, 2021 and 2020, respectively $ 41,520 $ 25,494 Cash paid for amounts included in the measurement of ground lease liabilities $ 2,887 $ 2,905 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 85,490 $ 131,892 Tenant improvements funded directly by tenants $ 4,265 $ 7,210 Assumption of accrued liabilities in connection with acquisitions (Notes 2 and 11) $ 37,572 $ — Initial measurement of operating right of use ground lease assets (Notes 2 and 11) $ 46,430 $ — Initial measurement of operating ground lease liabilities (Notes 2 and 11) $ 46,430 $ — NON-CASH FINANCING TRANSACTIONS: Accrual of dividends and distributions payable to common stockholders and common unitholders $ 59,455 $ 57,600 Exchange of common units of the Operating Partnership into shares of the Company’s common stock $ — $ 3,843 The following is a reconciliation of our cash and cash equivalents and restricted cash at the beginning and end of the six months ended June 30, 2021 and 2020. Six Months Ended June 30, 2021 2020 (in thousands) RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 731,991 $ 60,044 Restricted cash at beginning of period 91,139 16,300 Cash and cash equivalents and restricted cash at beginning of period $ 823,130 $ 76,344 Cash and cash equivalents at end of period $ 519,307 $ 605,012 Restricted cash at end of period 450,457 16,300 Cash and cash equivalents and restricted cash at end of period $ 969,764 $ 621,312

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information of the Operating Partnership	6 Months Ended
	Jun. 30, 2021
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 follows (in thousands): Six Months Ended June 30, 2021 2020 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $33,244 and $39,952 as of June 30, 2021 and 2020, respectively $ 41,520 $ 25,494 Cash paid for amounts included in the measurement of ground lease liabilities $ 2,887 $ 2,905 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 85,490 $ 131,892 Tenant improvements funded directly by tenants $ 4,265 $ 7,210 Assumption of accrued liabilities in connection with acquisitions (Notes 2 and 11) $ 37,572 $ — Initial measurement of operating right of use ground lease assets (Notes 2 and 11) $ 46,430 $ — Initial measurement of operating ground lease liabilities (Notes 2 and 11) $ 46,430 $ — NON-CASH FINANCING TRANSACTIONS: Accrual of dividends and distributions payable to common stockholders and common unitholders $ 59,455 $ 57,600 Exchange of common units of the Operating Partnership into shares of the Company’s common stock $ — $ 3,843 The following is a reconciliation of our cash and cash equivalents and restricted cash at the beginning and end of the six months ended June 30, 2021 and 2020. Six Months Ended June 30, 2021 2020 (in thousands) RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 731,991 $ 60,044 Restricted cash at beginning of period 91,139 16,300 Cash and cash equivalents and restricted cash at beginning of period $ 823,130 $ 76,344 Cash and cash equivalents at end of period $ 519,307 $ 605,012 Restricted cash at end of period 450,457 16,300 Cash and cash equivalents and restricted cash at end of period $ 969,764 $ 621,312
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 follows (in thousands): Six Months Ended June 30, 2021 2020 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $33,244 and $39,952 as of June 30, 2021 and 2020, respectively $ 41,520 $ 25,494 Cash paid for amounts included in the measurement of ground lease liabilities $ 2,887 $ 2,905 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 85,490 $ 131,892 Tenant improvements funded directly by tenants $ 4,265 $ 7,210 Assumption of accrued liabilities in connection with acquisitions (Notes 2 and 11) $ 37,572 $ — Initial measurement of operating right of use ground lease assets (Notes 2 and 11) $ 46,430 $ — Initial measurement of operating ground lease liabilities (Notes 2 and 11) $ 46,430 $ — NON-CASH FINANCING TRANSACTIONS: Accrual of distributions payable to common unitholders (Note 17) $ 59,455 $ 57,600 The following is a reconciliation of our cash and cash equivalents and restricted cash at the beginning and end of the six months ended June 30, 2021 and 2020. Six Months Ended June 30, 2021 2020 (in thousands) RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 731,991 $ 60,044 Restricted cash at beginning of period 91,139 16,300 Cash and cash equivalents and restricted cash at beginning of period $ 823,130 $ 76,344 Cash and cash equivalents at end of period $ 519,307 $ 605,012 Restricted cash at end of period 450,457 16,300 Cash and cash equivalents and restricted cash at end of period $ 969,764 $ 621,312

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On July 8, 2021, we completed the acquisition of the land that was subject to a ground lease underlying the property at 601 108th Avenue NE in Bellevue, Washington for $47.0 million. On July 14, 2021, aggregate dividends, distributions and dividend equivalents of $59.5 million were paid to common stockholders, common unitholders and RSU holders of record on June 30, 2021.

Organization, Ownership and B_2

Organization, Ownership and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2021
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, 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, 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, 2021. 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, 2020.

Organization, Ownership and B_3

Organization, Ownership and Basis of Presentation (Tables)	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of real estate properties	Our stabilized portfolio of operating properties was comprised of the following properties at June 30, 2021: Number of Rentable Number of Percentage Occupied (1) Percentage Leased Stabilized Office Properties (2) 118 14,151,674 427 91.8 % 93.6 % ________________________ (1) Represents physical and economic occupancy. (2) Includes stabilized life science and retail space. Number of Number of 2021 Average Occupancy Stabilized Residential Properties 3 1,001 70.6 % Number of Estimated Rentable Square Feet (1) In-process development projects - tenant improvement (2) 4 2,220,000 In-process development projects - under construction 2 1,110,000 ________________________ (1) Estimated rentable square feet upon completion.

Acquisitions (Tables)

Acquisitions (Tables)	6 Months Ended
	Jun. 30, 2021
Asset Acquisition [Abstract]
Schedule of acquisitions	During the six months ended June 30, 2021, we acquired the following development properties in two transactions from unrelated third parties. The acquisitions were funded with the proceeds from the operating property disposition completed during the three months ended March 31, 2021 that were temporarily being held by a qualified intermediary, at our discretion, for the purpose of facilitating a Section 1031 Exchange. Property Date of Acquisition Submarket Purchase Price (in millions) (1) 2045 Pacific Highway, San Diego, CA (2) June 22, 2021 Little Italy $ 42.0 200 W. 6th Street, Austin, TX (3) June 23, 2021 Austin CBD 580.2 Total $ 622.2 ________________________ (1) Excludes acquisition-related costs. (2) This property was added to our future development pipeline. In connection with this acquisition, we also recorded $5.2 million of environmental remediation liabilities as of the date of acquisition, which is not included in the purchase price above.

Dispositions (Tables)

Dispositions (Tables)	6 Months Ended
	Jun. 30, 2021
Discontinued Operations and Disposal Groups [Abstract]
Schedule of operating property dispositions	The following table summarizes the one operating property sold during the six months ended June 30, 2021: Property Month of Disposition Number of Buildings Rentable Square Feet Sales Price (in billions) (1) 1800 Owens Street, San Francisco, CA (The Exchange on 16th) March 1 750,370 $ 1.08 ___________________________

Prepaid Expenses and Other As_2

Prepaid Expenses and Other Assets, Net (Tables)	6 Months Ended
	Jun. 30, 2021
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 June 30, 2021 and December 31, 2020: June 30, 2021 December 31, 2020 (in thousands) Furniture, fixtures and other long-lived assets, net $ 40,679 $ 43,367 Prepaid expenses, acquisition deposits and other assets, net (1) 26,815 10,193 Total prepaid expenses and other assets, net $ 67,494 $ 53,560 ___________________________ (1) Includes $5.0 million of non-refundable acquisition deposits related to an acquisition which closed on July 8, 2021. 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]	6 Months Ended
	Jun. 30, 2021
Debt Instrument [Line Items]
Unsecured revolving credit facility	The following table summarizes the balance and terms of our unsecured revolving credit facility as of June 30, 2021 and December 31, 2020: June 30, 2021 December 31, 2020 (in thousands) Outstanding borrowings $ — $ — Remaining borrowing capacity 1,100,000 750,000 Total borrowing capacity (1) $ 1,100,000 $ 750,000 Interest rate (2) 1.00 % 1.14 % Facility fee-annual rate (3) 0.200% Maturity date July 2025 July 2022 ________________________ (1) We may elect to borrow, subject to bank approval and obtaining commitments for any additional borrowing capacity, up to an additional $500.0 million and $600.0 million as of June 30, 2021 and December 31, 2020, respectively, under an accordion feature under the terms of the unsecured revolving credit facility. (2) Our unsecured revolving credit facility interest rate was calculated based on the contractual rate of LIBOR plus 0.900% and LIBOR plus 1.000% as of June 30, 2021 and December 31, 2020, respectively. (3) Our facility fee is paid on a quarterly basis and is calculated based on the total borrowing capacity. In addition to the facility fee, we incurred debt origination and legal costs. As of June 30, 2021 and December 31, 2020, $8.3 million and $2.1 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 respective maturity dates presented of our unsecured revolving credit facility.
Schedule of debt maturities	The following table summarizes the stated debt maturities and scheduled amortization payments as of June 30, 2021: Year (in thousands) Remaining 2021 $ 2,698 2022 5,554 2023 305,775 2024 431,006 2025 406,246 2026 401,316 Thereafter 2,399,125 Total aggregate principal value (1) $ 3,951,720 ________________________
Capitalized interest and loan fees	The following table sets forth gross interest expense, including debt discount and deferred financing cost amortization, net of capitalized interest, for the three and six months ended June 30, 2021 and 2020. 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 June 30, Six Months Ended June 30, 2021 2020 2021 2020 (in thousands) Gross interest expense $ 39,463 $ 36,400 $ 78,705 $ 72,262 Capitalized interest and deferred financing costs (18,073) (20,516) (34,981) (41,934) Interest expense $ 21,390 $ 15,884 $ 43,724 $ 30,328

Partners' Capital of the Oper_2

Partners' Capital of the Operating Partnership (Tables)	6 Months Ended
	Jun. 30, 2021
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: June 30, 2021 December 31, 2020 June 30, 2020 Company owned common units in the Operating Partnership 116,454,210 116,035,827 115,176,538 Company owned general partnership interest 99.0 % 99.0 % 98.3 % Noncontrolling common units of the Operating Partnership 1,150,574 1,150,574 1,934,586 Ownership interest of noncontrolling interest 1.0 % 1.0 % 1.7 %

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2021
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 2021 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 the following grant date fair value per share. Fair Value Assumptions Valuation date February 18, 2021 Expected share price volatility 35.0% Risk-free interest rate 0.20% Fair value per share on valuation date (1) $63.93 ________________________ (1) Using the same Monte Carlo methodology and assumptions, the grant date fair value of one participant’s 2021 Performance-Based RSU grants was calculated as $66.95 per share.

Rental Income and Future Mini_2

Rental Income and Future Minimum Rent (Tables)	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Rental income	The table below sets forth the allocation of rental income between fixed and variable payments and collectability reversals for the three and six months ended June 30, 2021 and 2020: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 (in thousands) Fixed lease payments $ 197,846 $ 194,486 $ 402,062 $ 387,961 Variable lease payments 26,339 29,764 57,814 61,409 Net collectability recoveries (reversals) (1) 288 (5,894) (747) (12,381) Total rental income $ 224,473 $ 218,356 $ 459,129 $ 436,989 _____________________ (1) Represents adjustments to rental income related to our assessment of the collectability of amounts due under leases with our tenants. For the three and six months ended June 30, 2020, includes a reduction in revenue of $5.9 million and $12.4 million, respectively, primarily as a result of the COVID-19 pandemic.
Future contractual minimum rent under operating leases	Future contractual minimum rent under operating leases, which includes amounts contractually due from leases that are on a cash basis of reporting due to creditworthiness considerations, as of June 30, 2021 for future periods is summarized as follows: Year Ending (in thousands) Remaining 2021 $ 352,227 2022 782,849 2023 768,461 2024 728,204 2025 690,384 2026 635,807 Thereafter 2,509,266 Total (1) $ 6,467,198 _____________________ (1) Excludes residential leases and leases with a term of one year or less.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2021
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 as of June 30, 2021 and the respective contractual expiration dates: Property Contractual Expiration Date (1) 601 108th Ave NE, Bellevue, WA (2) November 2093 701, 801 and 837 N. 34th Street, Seattle, WA (3) 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 3243 S. La Cienega Boulevard, Los Angeles, CA October 2106 200 W. 6th St. Austin, TX (4) December 2112 ____________________ (1) Reflects the contractual expiration date prior to the impact of any extension or purchase options held by the Company. (2) In July 2021, we completed the acquisition of the land subject to this ground lease. Refer to Note 17 “Subsequent Events” for additional information. (3) 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 extension 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 June 30, 2021 for future periods is summarized as follows: Year Ending (in thousands) Remaining 2021 $ 3,699 2022 7,435 2023 7,489 2024 7,525 2025 7,561 2026 7,597 Thereafter 440,411 Total undiscounted cash flows (1)(2)(3)(4)(5)(6)(7) 481,717 Present value discount (337,832) Ground lease liabilities $ 143,885 ________________________ (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 June 30, 2021. (3) One of our ground lease obligations includes a component that 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 June 30, 2021 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 June 30, 2021 for the remainder of the lease term since we cannot predict future adjustments. (5) One of our ground lease obligations includes a component that 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 June 30, 2021 for the remainder of the lease term since we cannot predict future adjustments. (6) One of our ground lease obligations is subject to fixed 5% ground rent increases every five years, with the next increase occurring on December 1, 2022. (7) One of our ground lease obligations is subject to fixed 2% ground rent increases every year, with ground rent resets occurring every ten years based on CPI. The contractual obligations for that lease included above assume increases for the remaining current ten-year period based on the current annual ground lease obligation in effect at June 30, 2021 and no subsequent changes for the remainder of the lease term since we cannot predict future CPI adjustments.

Fair Value Measurements and D_2

Fair Value Measurements and Disclosures (Tables)	6 Months Ended
	Jun. 30, 2021
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 June 30, 2021 and December 31, 2020: Fair Value (Level 1) (1) June 30, 2021 December 31, 2020 Description (in thousands) Marketable securities (2) $ 25,885 $ 27,481 ________________________ (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 six months ended June 30, 2021 and 2020: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Description (in thousands) (in thousands) Net gain (loss) on marketable securities $ 1,261 $ 2,662 $ 2,565 $ (564)
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 June 30, 2021 and December 31, 2020: June 30, 2021 December 31, 2020 Carrying Fair (1) Carrying Fair (1) (in thousands) Liabilities Secured debt, net $ 251,000 $ 278,882 $ 253,582 $ 282,559 Unsecured debt, net $ 3,672,152 $ 4,014,791 $ 3,670,099 $ 4,089,339 ________________________ (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)	6 Months Ended
	Jun. 30, 2021
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 six months ended June 30, 2021 and 2020: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 (in thousands, except share and per share amounts) Numerator: Net income available to common stockholders $ 35,839 $ 19,618 $ 533,470 $ 59,435 Allocation to participating securities (1) (371) (542) (736) (1,085) Numerator for basic and diluted net income available to common stockholders $ 35,468 $ 19,076 $ 532,734 $ 58,350 Denominator: Basic weighted average vested shares outstanding 116,451,931 115,084,897 116,398,450 110,980,066 Effect of dilutive securities 465,532 454,828 461,295 484,581 Diluted weighted average vested shares and common stock equivalents outstanding 116,917,463 115,539,725 116,859,745 111,464,647 Basic earnings per share: Net income available to common stockholders per share $ 0.30 $ 0.17 $ 4.58 $ 0.53 Diluted earnings per share: Net income available to common stockholders per share $ 0.30 $ 0.17 $ 4.56 $ 0.52 ________________________

Net Income Available to Commo_4

Net Income Available to Common Unitholders Per Unit of the Operating Partnership (Tables)	6 Months Ended
	Jun. 30, 2021
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 six months ended June 30, 2021 and 2020: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 (in thousands, except share and per share amounts) Numerator: Net income available to common stockholders $ 35,839 $ 19,618 $ 533,470 $ 59,435 Allocation to participating securities (1) (371) (542) (736) (1,085) Numerator for basic and diluted net income available to common stockholders $ 35,468 $ 19,076 $ 532,734 $ 58,350 Denominator: Basic weighted average vested shares outstanding 116,451,931 115,084,897 116,398,450 110,980,066 Effect of dilutive securities 465,532 454,828 461,295 484,581 Diluted weighted average vested shares and common stock equivalents outstanding 116,917,463 115,539,725 116,859,745 111,464,647 Basic earnings per share: Net income available to common stockholders per share $ 0.30 $ 0.17 $ 4.58 $ 0.53 Diluted earnings per share: Net income available to common stockholders per share $ 0.30 $ 0.17 $ 4.56 $ 0.52 ________________________
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 six months ended June 30, 2021 and 2020: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 (in thousands, except unit and per unit amounts) Numerator: Net income available to common unitholders $ 36,193 $ 19,838 $ 538,710 $ 60,227 Allocation to participating securities (1) (371) (542) (736) (1,085) Numerator for basic and diluted net income available to common unitholders $ 35,822 $ 19,296 $ 537,974 $ 59,142 Denominator: Basic weighted average vested units outstanding 117,602,505 117,098,562 117,549,024 112,997,795 Effect of dilutive securities 465,532 454,828 461,295 484,581 Diluted weighted average vested units and common unit equivalents outstanding 118,068,037 117,553,390 118,010,319 113,482,376 Basic earnings per unit: Net income available to common unitholders per unit $ 0.30 $ 0.16 $ 4.58 $ 0.52 Diluted earnings per unit: Net income available to common unitholders per unit $ 0.30 $ 0.16 $ 4.56 $ 0.52 ________________________

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information of the Company (Tables)	6 Months Ended
	Jun. 30, 2021
Supplemental Cash Flow Elements [Abstract]
Schedule of supplemental cash flows	Supplemental cash flow information follows (in thousands): Six Months Ended June 30, 2021 2020 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $33,244 and $39,952 as of June 30, 2021 and 2020, respectively $ 41,520 $ 25,494 Cash paid for amounts included in the measurement of ground lease liabilities $ 2,887 $ 2,905 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 85,490 $ 131,892 Tenant improvements funded directly by tenants $ 4,265 $ 7,210 Assumption of accrued liabilities in connection with acquisitions (Notes 2 and 11) $ 37,572 $ — Initial measurement of operating right of use ground lease assets (Notes 2 and 11) $ 46,430 $ — Initial measurement of operating ground lease liabilities (Notes 2 and 11) $ 46,430 $ — NON-CASH FINANCING TRANSACTIONS: Accrual of dividends and distributions payable to common stockholders and common unitholders $ 59,455 $ 57,600 Exchange of common units of the Operating Partnership into shares of the Company’s common stock $ — $ 3,843
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 six months ended June 30, 2021 and 2020. Six Months Ended June 30, 2021 2020 (in thousands) RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 731,991 $ 60,044 Restricted cash at beginning of period 91,139 16,300 Cash and cash equivalents and restricted cash at beginning of period $ 823,130 $ 76,344 Cash and cash equivalents at end of period $ 519,307 $ 605,012 Restricted cash at end of period 450,457 16,300 Cash and cash equivalents and restricted cash at end of period $ 969,764 $ 621,312
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 six months ended June 30, 2021 and 2020. Six Months Ended June 30, 2021 2020 (in thousands) RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 731,991 $ 60,044 Restricted cash at beginning of period 91,139 16,300 Cash and cash equivalents and restricted cash at beginning of period $ 823,130 $ 76,344 Cash and cash equivalents at end of period $ 519,307 $ 605,012 Restricted cash at end of period 450,457 16,300 Cash and cash equivalents and restricted cash at end of period $ 969,764 $ 621,312

Supplemental Cash Flow Inform_4

Supplemental Cash Flow Information of the Operating Partnership (Tables)	6 Months Ended
	Jun. 30, 2021
Other Significant Noncash Transactions [Line Items]
Schedule of supplemental cash flows	Supplemental cash flow information follows (in thousands): Six Months Ended June 30, 2021 2020 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $33,244 and $39,952 as of June 30, 2021 and 2020, respectively $ 41,520 $ 25,494 Cash paid for amounts included in the measurement of ground lease liabilities $ 2,887 $ 2,905 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 85,490 $ 131,892 Tenant improvements funded directly by tenants $ 4,265 $ 7,210 Assumption of accrued liabilities in connection with acquisitions (Notes 2 and 11) $ 37,572 $ — Initial measurement of operating right of use ground lease assets (Notes 2 and 11) $ 46,430 $ — Initial measurement of operating ground lease liabilities (Notes 2 and 11) $ 46,430 $ — NON-CASH FINANCING TRANSACTIONS: Accrual of dividends and distributions payable to common stockholders and common unitholders $ 59,455 $ 57,600 Exchange of common units of the Operating Partnership into shares of the Company’s common stock $ — $ 3,843
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 six months ended June 30, 2021 and 2020. Six Months Ended June 30, 2021 2020 (in thousands) RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 731,991 $ 60,044 Restricted cash at beginning of period 91,139 16,300 Cash and cash equivalents and restricted cash at beginning of period $ 823,130 $ 76,344 Cash and cash equivalents at end of period $ 519,307 $ 605,012 Restricted cash at end of period 450,457 16,300 Cash and cash equivalents and restricted cash at end of period $ 969,764 $ 621,312
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 six months ended June 30, 2021 and 2020. Six Months Ended June 30, 2021 2020 (in thousands) RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 731,991 $ 60,044 Restricted cash at beginning of period 91,139 16,300 Cash and cash equivalents and restricted cash at beginning of period $ 823,130 $ 76,344 Cash and cash equivalents at end of period $ 519,307 $ 605,012 Restricted cash at end of period 450,457 16,300 Cash and cash equivalents and restricted cash at end of period $ 969,764 $ 621,312
Kilroy Realty L.P. [Member]
Other Significant Noncash Transactions [Line Items]
Schedule of supplemental cash flows	Supplemental cash flow information follows (in thousands): Six Months Ended June 30, 2021 2020 SUPPLEMENTAL CASH FLOWS INFORMATION: Cash paid for interest, net of capitalized interest of $33,244 and $39,952 as of June 30, 2021 and 2020, respectively $ 41,520 $ 25,494 Cash paid for amounts included in the measurement of ground lease liabilities $ 2,887 $ 2,905 NON-CASH INVESTING TRANSACTIONS: Accrual for expenditures for operating properties and development properties $ 85,490 $ 131,892 Tenant improvements funded directly by tenants $ 4,265 $ 7,210 Assumption of accrued liabilities in connection with acquisitions (Notes 2 and 11) $ 37,572 $ — Initial measurement of operating right of use ground lease assets (Notes 2 and 11) $ 46,430 $ — Initial measurement of operating ground lease liabilities (Notes 2 and 11) $ 46,430 $ — NON-CASH FINANCING TRANSACTIONS: Accrual of distributions payable to common unitholders (Note 17) $ 59,455 $ 57,600
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 six months ended June 30, 2021 and 2020. Six Months Ended June 30, 2021 2020 (in thousands) RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 731,991 $ 60,044 Restricted cash at beginning of period 91,139 16,300 Cash and cash equivalents and restricted cash at beginning of period $ 823,130 $ 76,344 Cash and cash equivalents at end of period $ 519,307 $ 605,012 Restricted cash at end of period 450,457 16,300 Cash and cash equivalents and restricted cash at end of period $ 969,764 $ 621,312
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 six months ended June 30, 2021 and 2020. Six Months Ended June 30, 2021 2020 (in thousands) RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH: Cash and cash equivalents at beginning of period $ 731,991 $ 60,044 Restricted cash at beginning of period 91,139 16,300 Cash and cash equivalents and restricted cash at beginning of period $ 823,130 $ 76,344 Cash and cash equivalents at end of period $ 519,307 $ 605,012 Restricted cash at end of period 450,457 16,300 Cash and cash equivalents and restricted cash at end of period $ 969,764 $ 621,312

Organization, Ownership and B_4

Organization, Ownership and Basis of Presentation - Operating Properties (Details)	6 Months Ended
	Jun. 30, 2021ft²projectpropertytenantbuilding
Stabilized office properties [Member]
Real Estate Properties [Line Items]
Number of Buildings | property	118
Rentable Square Feet	14,151,674
Number of Tenants | tenant	427
Percentage Occupied	91.80%
Percentage Leased	93.60%
Stabilized residential properties [Member]
Real Estate Properties [Line Items]
Number of properties | building	3
Number of Units | building	1,001
2021 Average Occupancy	70.60%
In-process development projects - tenant improvement [Member]
Real Estate Properties [Line Items]
Rentable Square Feet	2,220,000
Number of properties | project	4
In-process development projects - under construction [Member]
Real Estate Properties [Line Items]
Rentable Square Feet	1,110,000
Number of properties | project	2

Organization, Ownership and B_5

Organization, Ownership and Basis of Presentation - Narrative (Details) $ in Thousands	Jun. 30, 2021USD ($)aft²propertyproperty_partnershipresidential_unitbuildingVIEproject	Dec. 31, 2020USD ($)VIE	Jun. 30, 2020	Jun. 30, 2021USD ($)aft²propertyproperty_partnershipresidential_unitbuildingVIEproject
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
Assets | $	$ 10,434,766	$ 10,000,708		$ 10,434,766
Liabilities | $	4,741,301	4,723,387		4,741,301
Noncontrolling interest in VIE | $	$ 192,712	$ 197,503		$ 192,712
Washington [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties	1			1
San Francisco, California [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties | building	1			1
Stabilized office properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of buildings	118			118
Rentable square feet | ft²	14,151,674			14,151,674
Stabilized office properties [Member] | Washington [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties	8			8
Development properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties	3			3
Number of property partnerships | property_partnership	3			3
Development properties [Member] | San Diego, California [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Rentable square feet | ft²	252,486			252,486
Development properties [Member] | Hollywood, California [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of residential units | residential_unit	193			193
Development properties [Member] | Washington [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties	1			1
Development properties [Member] | Texas [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties	1			1
Operating Properties [Member] | San Diego, California [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of buildings	2			2
Office properties owned by consolidated property partnerships [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties	4			4
Development sites [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties | project	6			6
Area of undeveloped land | a	59			59
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%
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%			56.00%
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			2
Redwood LLC [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of properties	2			2
Company owned general partnership interest	93.00%			93.00%
Operating Partnership [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Ownership interest (percent)	99.00%	99.00%	98.30%
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 (percent)	1.00%	1.00%	1.70%
Variable Interest Entity, Primary Beneficiary [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of VIEs | VIE	3	2		3
Assets | $	$ 461,700	$ 469,300		$ 461,700
Liabilities | $	28,100	33,900		28,100
Variable Interest Entity, Primary Beneficiary [Member] | Real estate investment [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Assets | $	393,600	394,600		393,600
Variable Interest Entity, Primary Beneficiary [Member] | 101 First LLC and 303 Second LLC [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling interest in VIE | $	$ 187,200	$ 191,900		$ 187,200
Variable Interest Entity, Primary Beneficiary [Member] | Operating Partnership [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of VIEs | VIE	2			2
Variable Interest Entity, Primary Beneficiary [Member] | Entity Established to Facilitate Potential Future Section 1031 Exchanges [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of VIEs | VIE	1			1

Acquisitions (Details)

Acquisitions (Details) $ in Thousands	Jun. 23, 2021USD ($)	Jun. 22, 2021USD ($)	Jun. 30, 2021USD ($)numberofaquisitiontransactions	Dec. 31, 2020USD ($)
Schedule of Asset Acquisitions, by Acquisition [Line Items]
Number of development property transactions | numberofaquisitiontransactions			2
Purchase price			$ 622,200
Ground lease right-of-use asset			141,529	$ 95,523
Ground lease liabilities			$ 143,885	$ 97,778
2045 Pacific Highway, San Diego, CA [Member]
Schedule of Asset Acquisitions, by Acquisition [Line Items]
Purchase price		$ 42,000
Accrued environmental remediation liabilities		$ 5,200
200 W. 6th Street, Austin, TX [Member]
Schedule of Asset Acquisitions, by Acquisition [Line Items]
Purchase price	$ 580,200
Ground lease right-of-use asset	46,400
Ground lease liabilities	$ 46,400
Discount rate (percent)	3.97%

Dispositions and Real Estate He

Dispositions and Real Estate Held for Sale - Operating Property Dispositions (Details) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Mar. 31, 2021USD ($)ft²building	Jun. 30, 2021USD ($)building	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)building	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of depreciable operating property		$ 543	$ 0	$ 457,831	$ 0
Restricted cash		450,457	$ 16,300	450,457	$ 16,300	$ 91,139	$ 16,300
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restricted cash		$ 431,500		$ 431,500
Operating Properties [Member] | 1800 Owens Street, San Francisco, CA [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties | building	1	1		1
Rentable square feet | ft²	750,370
Sales price	$ 1,080,000

Prepaid Expenses and Other As_3

Prepaid Expenses and Other Assets, Net (Details) - USD ($) $ in Thousands	Jul. 08, 2021	Jun. 30, 2021	Dec. 31, 2020
Subsequent Event [Line Items]
Furniture, fixtures and other long-lived assets, net		$ 40,679	$ 43,367
Prepaid expenses, acquisition deposits and other assets, net (1)		26,815	10,193
Total prepaid expenses and other assets, net		$ 67,494	$ 53,560
Subsequent event [Member]
Subsequent Event [Line Items]
Prepaid expenses, acquisition deposits and other assets, net (1)	$ 5,000

Secured and Unsecured Debt of_3

Secured and Unsecured Debt of the Operating Partnership - Unsecured Senior Notes, Unsecured Revolving Credit Facility and Term Loan Facility (Details) - Kilroy Realty L.P. [Member] - Revolving credit facility [Member] - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020	Apr. 29, 2021
Terms of the Credit Facility
Outstanding borrowings	$ 0	$ 0
Remaining borrowing capacity	1,100,000,000	750,000,000
Total borrowing capacity	$ 1,100,000,000	$ 750,000,000	$ 1,100,000,000
Interest rate (percent)	1.00%	1.14%
Facility fee-annual rate (percent)	0.20%	0.20%
Contingent additional borrowings	$ 500,000,000	$ 600,000,000
Unamortized deferred financing costs	$ 8,300,000	$ 2,100,000
London Interbank Offered Rate (LIBOR) [Member]
Terms of the Credit Facility
Variable rate (percent)	0.90%	1.00%

Secured and Unsecured Debt of_4

Secured and Unsecured Debt of the Operating Partnership - Additional Information (Details) - Kilroy Realty L.P. [Member] - Revolving credit facility [Member]	1 Months Ended
	Apr. 29, 2021USD ($)extensionOption	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Maximum borrowing capacity | $	$ 1,100,000,000	$ 1,100,000,000	$ 750,000,000
Number of extension options | extensionOption	2
Extension period	6 months
Interest rate reduction if sustainability performance targets met (percent)	0.01%

Secured and Unsecured Debt of_5

Secured and Unsecured Debt of the Operating Partnership - Debt Maturities (Details) - Kilroy Realty L.P. [Member] $ in Thousands	Jun. 30, 2021USD ($)
Stated debt maturities and scheduled amortization payments
Remaining 2021	$ 2,698
2022	5,554
2023	305,775
2024	431,006
2025	406,246
2026	401,316
Thereafter	2,399,125
Total debt	3,951,720
Unsecured term loan facility, unsecured senior notes and secured debt [Member]
Stated debt maturities and scheduled amortization payments
Unamortized deferred financing costs	20,800
Unsecured senior notes [Member]
Stated debt maturities and scheduled amortization payments
Unamortized discount	$ 7,700

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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Capitalized Interest and Loan Fees [Line Items]
Interest expense	$ 21,390	$ 15,884	$ 43,724	$ 30,328
Kilroy Realty L.P. [Member]
Capitalized Interest and Loan Fees [Line Items]
Gross interest expense	39,463	36,400	78,705	72,262
Capitalized interest and deferred financing costs	(18,073)	(20,516)	(34,981)	(41,934)
Interest expense	$ 21,390	$ 15,884	$ 43,724	$ 30,328

Stockholders' Equity of the C_2

Stockholders' Equity of the Company (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Jun. 30, 2018
Class of Stock [Line Items]
At the market stock offering aggregate gross sales price of common stock				$ 500,000,000
Common stock, shares issued (in shares)	116,454,210		116,035,827
Proceeds from issuance of stock	$ 0	$ 721,749,000
Common Stock [Member] | Forward equity sale [Member]
Class of Stock [Line Items]
Common stock, shares issued (in shares)	3,594,576
At the market stock offering remaining amount available for issuance	$ 214,200,000
Proceeds from issuance of stock	$ 0

Noncontrolling Interests on t_2

Noncontrolling Interests on the Company's Consolidated Financial Statements (Details) $ / shares in Units, $ in Millions	Jun. 30, 2021USD ($)$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares	Jun. 30, 2020shares	Jun. 30, 2021USD ($)trading_day$ / sharesshares
Noncontrolling Interest [Line Items]
Common stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01		$ 0.01
Number of trading days | trading_day				10
Aggregate value upon redemption of outstanding noncontrolling common units | $	$ 81.7	$ 65.4		$ 81.7
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) | shares	1,150,574	1,150,574	1,934,586	1,150,574
Operating Partnership [Member]
Noncontrolling Interest [Line Items]
Ownership interest (percent)	99.00%	99.00%	98.30%
Operating Partnership [Member] | Non-affiliated investors and certain of our executive officers and directors [Member]
Noncontrolling Interest [Line Items]
Ownership interest (percent)	1.00%	1.00%	1.70%

Partners' Capital of the Oper_3

Partners' Capital of the Operating Partnership (Details) - shares	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Operating Partnership [Member]
General Partners' Capital Account [Abstract]
Ownership interest (percent)	99.00%	99.00%	98.30%
Kilroy Realty L.P. [Member] | Common units [Member]
General Partners' Capital Account [Abstract]
Company owned common units in the Operating Partnership (in units)	116,454,210	116,035,827	115,176,538
Noncontrolling common units of the Operating Partnership (in units)	1,150,574	1,150,574
Non-affiliated investors and certain of our executive officers and directors [Member] | Operating Partnership [Member]
General Partners' Capital Account [Abstract]
Ownership interest (percent)	1.00%	1.00%	1.70%
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 (in units)	1,150,574	1,150,574	1,934,586

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions	Feb. 18, 2021USD ($)$ / shares	Feb. 28, 2021USD ($)participantinstallmentshares	Jun. 30, 2021USD ($)compensation_planshares	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)compensation_planshares	Jun. 30, 2020USD ($)	Jan. 29, 2021$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share-based incentive compensation plans | compensation_plan			1		1
Effective registration shares (in shares) | shares			10,700,000		10,700,000
Number of shares available for grant (in shares) | shares			1,400,000		1,400,000
Share-based compensation expense			$ 11.2	$ 13.6	$ 20.8	$ 22.2
Share-based compensation expense capitalized			1.7	$ 2	3.4	$ 3.9
Share-based compensation not yet recognized			41.8		$ 41.8
Share-based compensation not yet recognized period of recognition					1 year 6 months
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted in period (in shares) | shares		332,707
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) | shares		172,430
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) | shares		160,277
Time-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Number of participants with compensation expense recognized on a rolling twelve-month basis | participant		1
Number of installments | installment		3
Right to receive number of shares (in shares) | shares		1
Time-Based Restricted Stock Units (RSUs), Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share price | $ / shares	$ 57.85						$ 56.63
Fair value RSUs granted		$ 9.1
2021 Performance-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Vesting, achievement of pre-set FFO per share goals, percentage of RSUs		100.00%
Vesting, Average debt to EBIDTA ratio, percentage of RSUs		50.00%
Vesting, Market measure, percentage of RSUs		50.00%
Number of shares issuable per RSU		1
Share price | $ / shares	57.85
Fair value per share on valuation date (in dollars per share) | $ / shares	$ 63.93
Remaining expected life, including future volatility		2 years 10 months 24 days
Performance period		2 years 10 months 24 days
Fair value RSUs granted	$ 10.6
Share-based compensation expense					$ 2.8
2020 Performance-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based RSU, achievement target, all other participants, percent					150.00%
Performance-based RSU, achievement target, one participant, percent					175.00%
Accelerated Compensation Related to Severance Packages [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense			$ 4.1		$ 4.3

Share-Based Compensation - Fair

Share-Based Compensation - Fair Value Assumptions (Details) - 2021 Performance-Based RSUs [Member]	Feb. 18, 2021$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected share price volatility	35.00%
Risk-free interest rate	0.20%
Fair value per share on valuation date (in dollars per share)	$ 63.93
One Participant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value per share on valuation date (in dollars per share)	$ 66.95

Rental Income and Future Mini_3

Rental Income and Future Minimum Rent - Rental income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Leases [Abstract]
Fixed lease payments	$ 197,846	$ 194,486	$ 402,062	$ 387,961
Variable lease payments	26,339	29,764	57,814	61,409
Collectability reversals	288	(5,894)	(747)	(12,381)
Total rental income	$ 224,473	218,356	$ 459,129	436,989
Reduction of revenue primarily as a result of the COVID-19 pandemic		$ (5,900)		$ (12,400)

Rental Income and Future Mini_4

Rental Income and Future Minimum Rent - Future Contractual Minimum Rent (Details) $ in Thousands	Jun. 30, 2021USD ($)
Future contractual minimum rent under operating lease
Remaining 2021	$ 352,227
2022	782,849
2023	768,461
2024	728,204
2025	690,384
2026	635,807
Thereafter	2,509,266
Total	$ 6,467,198

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)ground_lease	Jun. 30, 2020USD ($)
Long-term Purchase Commitment [Line Items]
Commitments for contracts and executed leases, operating and redevelopment and development properties	$ 1,000		$ 1,000
Weighted average discount rate, ground leases	4.74%		4.74%
Weighted average remaining lease term	66 years		66 years
Variable lease, cost	$ 0.6	$ 0.9	$ 0.9	$ 1.7
Environmental matters [Member]
Long-term Purchase Commitment [Line Items]
Accrued environmental remediation liabilities	$ 77.6		$ 77.6
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	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Minimum commitment under our ground leases
Remaining 2021	$ 3,699
2022	7,435
2023	7,489
2024	7,525
2025	7,561
2026	7,597
Thereafter	440,411
Total undiscounted cash flows	481,717
Present value discount	(337,832)
Ground lease liabilities	$ 143,885	$ 97,778
Period after which ground lease rentals are adjusted based on fair market value and the Consumer Price Index	5 years
Annual ground lease rental obligations limit	$ 1,000
Average annual percentage rent for previous five years (percent)	50.00%
Previous period included in average annual rent percentage for five-year increases	5 years
Duration of ground lease increase	10 years
Average annual percentage rent for previous ten years (percent)	60.00%
Previous period included in average annual rent percentage for ten-year increases	3 years
Percentage rent increase every five years	5.00%
Percentage rent increase every year	2.00%
Ground lease reset period	10 years
Remaining ground lease obligation period	10 years

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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Fair value adjustment of marketable securities and deferred compensation plan liability
Net gain (loss) on marketable securities	$ 1,261	$ 2,662	$ 2,565	$ (564)
Fair value, measurements, recurring [Member] | Fair value (Level 1) [Member]
Assets and Liabilities Reported at Fair Value
Marketable securities	$ 25,885		$ 25,885		$ 27,481

Fair Value Measurements and D_4

Fair Value Measurements and Disclosures - Financial Instruments Disclosed at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Carrying value [Member] | Secured debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt, net	$ 251,000	$ 253,582
Carrying value [Member] | Unsecured debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt, net	3,672,152	3,670,099
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	278,882	282,559
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	$ 4,014,791	$ 4,089,339

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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net income available to common stockholders	$ 35,839	$ 19,618	$ 533,470	$ 59,435
Allocation to participating securities	(371)	(542)	(736)	(1,085)
Numerator for basic and diluted net income available to common stockholders	$ 35,468	$ 19,076	$ 532,734	$ 58,350
Denominator:
Basic weighted average vested shares outstanding (in shares)	116,451,931	115,084,897	116,398,450	110,980,066
Effect of dilutive securities (in shares)	465,532	454,828	461,295	484,581
Diluted weighted average vested shares and common stock equivalents outstanding (in shares)	116,917,463	115,539,725	116,859,745	111,464,647
Basic earnings per share:
Net income available to common stockholders per share (in dollars per share)	$ 0.30	$ 0.17	$ 4.58	$ 0.53
Diluted earnings per share:
Net income available to common stockholders per share (in dollars per share)	$ 0.30	$ 0.17	$ 4.56	$ 0.52

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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net income available to common unitholders	$ 35,839	$ 19,618	$ 533,470	$ 59,435
Allocation to participating securities	(371)	(542)	(736)	(1,085)
Numerator for basic and diluted net income available to common stockholders	$ 35,468	$ 19,076	$ 532,734	$ 58,350
Denominator:
Basic weighted average vested shares outstanding (in shares)	116,451,931	115,084,897	116,398,450	110,980,066
Effect of dilutive securities (in shares)	465,532	454,828	461,295	484,581
Diluted weighted average vested shares and common stock equivalents outstanding (in shares)	116,917,463	115,539,725	116,859,745	111,464,647
Basic earnings per unit:
Net income available to common stockholders per share (in dollars per share)	$ 0.30	$ 0.17	$ 4.58	$ 0.53
Diluted earnings per unit:
Net income available to common stockholders per share (in dollars per share)	$ 0.30	$ 0.17	$ 4.56	$ 0.52
Kilroy Realty L.P. [Member]
Numerator:
Net income available to common unitholders	$ 36,193	$ 19,838	$ 538,710	$ 60,227
Allocation to participating securities	(371)	(542)	(736)	(1,085)
Numerator for basic and diluted net income available to common stockholders	$ 35,822	$ 19,296	$ 537,974	$ 59,142
Denominator:
Basic weighted average vested shares outstanding (in shares)	117,602,505	117,098,562	117,549,024	112,997,795
Effect of dilutive securities (in shares)	465,532	454,828	461,295	484,581
Diluted weighted average vested shares and common stock equivalents outstanding (in shares)	118,068,037	117,553,390	118,010,319	113,482,376
Basic earnings per unit:
Net income available to common stockholders per share (in dollars per share)	$ 0.30	$ 0.16	$ 4.58	$ 0.52
Diluted earnings per unit:
Net income available to common stockholders per share (in dollars per share)	$ 0.30	$ 0.16	$ 4.56	$ 0.52

Supplemental Cash Flow Inform_5

Supplemental Cash Flow Information of the Company - Supplemental Cash Flow (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
SUPPLEMENTAL CASH FLOWS INFORMATION:
Cash paid for interest, net of capitalized interest of $33,244 and $39,952 as of June 30, 2021 and 2020, respectively	$ 41,520	$ 25,494
Capitalized interest	33,244	39,952
Cash paid for amounts included in the measurement of ground lease liabilities	2,887	2,905
NON-CASH INVESTING TRANSACTIONS:
Accrual for expenditures for operating properties and development properties	85,490	131,892
Tenant improvements funded directly by tenants	4,265	7,210
Assumption of accrued liabilities in connection with acquisitions (Notes 2 and 11)	37,572	0
Initial measurement of operating right of use ground lease assets (Notes 2 and 11)	46,430	0
Initial measurement of operating ground lease liabilities (Notes 2 and 11)	46,430	0
NON-CASH FINANCING TRANSACTIONS:
Accrual of dividends and distributions payable to common stockholders and common unitholders (Note 17)	59,455	57,600
Exchange of common units of the Operating Partnership into shares of the Company’s common stock	$ 0	$ 3,843

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	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH:
Cash and cash equivalents	$ 519,307	$ 731,991	$ 605,012	$ 60,044
Restricted cash	450,457	91,139	16,300	16,300
Cash and cash equivalents and restricted cash	$ 969,764	$ 823,130	$ 621,312	$ 76,344

Supplemental Cash Flow Inform_7

Supplemental Cash Flow Information of the Operating Partnership - Supplemental Cash Flow (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
SUPPLEMENTAL CASH FLOWS INFORMATION:
Cash paid for interest, net of capitalized interest of $33,244 and $39,952 as of June 30, 2021 and 2020, respectively	$ 41,520	$ 25,494
Capitalized interest	33,244	39,952
Cash paid for amounts included in the measurement of ground lease liabilities	2,887	2,905
NON-CASH INVESTING TRANSACTIONS:
Accrual for expenditures for operating properties and development properties	85,490	131,892
Tenant improvements funded directly by tenants	4,265	7,210
Assumption of accrued liabilities in connection with acquisitions (Notes 2 and 11)	37,572	0
Initial measurement of operating right of use ground lease assets (Notes 2 and 11)	46,430	0
Initial measurement of operating ground lease liabilities (Notes 2 and 11)	46,430	0
NON-CASH FINANCING TRANSACTIONS:
Accrual of distributions payable to common unitholders (Note 17)	59,455	57,600
Kilroy Realty L.P. [Member]
SUPPLEMENTAL CASH FLOWS INFORMATION:
Cash paid for interest, net of capitalized interest of $33,244 and $39,952 as of June 30, 2021 and 2020, respectively	41,520	25,494
Capitalized interest	33,244	39,952
Cash paid for amounts included in the measurement of ground lease liabilities	2,887	2,905
NON-CASH INVESTING TRANSACTIONS:
Accrual for expenditures for operating properties and development properties	85,490	131,892
Tenant improvements funded directly by tenants	4,265	7,210
Assumption of accrued liabilities in connection with acquisitions (Notes 2 and 11)	37,572	0
Initial measurement of operating right of use ground lease assets (Notes 2 and 11)	46,430	0
Initial measurement of operating ground lease liabilities (Notes 2 and 11)	46,430	0
NON-CASH FINANCING TRANSACTIONS:
Accrual of distributions payable to common unitholders (Note 17)	$ 59,455	$ 57,600

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	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH:
Cash and cash equivalents	$ 519,307	$ 731,991	$ 605,012	$ 60,044
Restricted cash	450,457	91,139	16,300	16,300
Cash and cash equivalents and restricted cash	969,764	823,130	621,312	76,344
Kilroy Realty L.P. [Member]
RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH:
Cash and cash equivalents	519,307	731,991	605,012	60,044
Restricted cash	450,457	91,139	16,300	16,300
Cash and cash equivalents and restricted cash	$ 969,764	$ 823,130	$ 621,312	$ 76,344

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Millions	Jul. 14, 2021	Jul. 08, 2021	Jun. 30, 2021
Subsequent Event [Line Items]
Purchase price			$ 622.2
Subsequent event [Member]
Subsequent Event [Line Items]
Payment of dividends	$ 59.5
Subsequent event [Member] | 601 108th Avenue NE, Bellevue, WA [Member]
Subsequent Event [Line Items]
Purchase price		$ 47