Consolidated Balance Sheets (KILROY REALTY, L.P.) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
REAL ESTATE ASSETS (Note 2):
Land and improvements	$ 1,127,100	$ 1,076,172
Buildings and improvements	5,056,050	4,908,797
Undeveloped land and construction in progress	2,146,430	1,432,808
Total real estate assets held for investment	8,329,580	7,417,777
Accumulated depreciation and amortization	(1,411,529)	(1,264,162)
Total real estate assets held for investment, net	6,918,051	6,153,615
CASH AND CASH EQUIVALENTS	86,517	57,649
RESTRICTED CASH	0	9,149
MARKETABLE SECURITIES (Note 11)	23,353	20,674
CURRENT RECEIVABLES, NET (Note 3)	17,519	16,926
DEFERRED RENT RECEIVABLES, NET (Note 3)	261,003	246,391
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET	183,118	183,728
PREPAID EXPENSES AND OTHER ASSETS, NET (Note 4)	72,675	114,706
TOTAL ASSETS	7,562,236	6,802,838
LIABILITIES:
Secured debt, net (Notes 5 and 11)	336,866	340,800
Unsecured debt, net (Notes 5 and 11)	2,207,049	2,006,263
Unsecured line of credit (Notes 5, 11 and 17)	330,000	0
Accounts payable, accrued expenses and other liabilities	360,674	249,637
Accrued distributions (Note 17)	47,411	43,448
Deferred revenue and acquisition-related intangible liabilities, net	149,059	145,890
Rents received in advance and tenant security deposits	56,258	56,484
Total liabilities	3,487,317	2,842,522
COMMITMENTS AND CONTINGENCIES (Note 10)
CAPITAL:
TOTAL LIABILITIES AND EQUITY (CAPITAL)	7,562,236	6,802,838
Kilroy Realty L.P. [Member]
REAL ESTATE ASSETS (Note 2):
Land and improvements	1,127,100	1,076,172
Buildings and improvements	5,056,050	4,908,797
Undeveloped land and construction in progress	2,146,430	1,432,808
Total real estate assets held for investment	8,329,580	7,417,777
Accumulated depreciation and amortization	(1,411,529)	(1,264,162)
Total real estate assets held for investment, net	6,918,051	6,153,615
CASH AND CASH EQUIVALENTS	86,517	57,649
RESTRICTED CASH	0	9,149
MARKETABLE SECURITIES (Note 11)	23,353	20,674
CURRENT RECEIVABLES, NET (Note 3)	17,519	16,926
DEFERRED RENT RECEIVABLES, NET (Note 3)	261,003	246,391
DEFERRED LEASING COSTS AND ACQUISITION-RELATED INTANGIBLE ASSETS, NET	183,118	183,728
PREPAID EXPENSES AND OTHER ASSETS, NET (Note 4)	72,675	114,706
TOTAL ASSETS	7,562,236	6,802,838
LIABILITIES:
Secured debt, net (Notes 5 and 11)	336,866	340,800
Unsecured debt, net (Notes 5 and 11)	2,207,049	2,006,263
Unsecured line of credit (Notes 5, 11 and 17)	330,000	0
Accounts payable, accrued expenses and other liabilities	360,674	249,637
Accrued distributions (Note 17)	47,411	43,448
Deferred revenue and acquisition-related intangible liabilities, net	149,059	145,890
Rents received in advance and tenant security deposits	56,258	56,484
Total liabilities	3,487,317	2,842,522
COMMITMENTS AND CONTINGENCIES (Note 10)
CAPITAL:
Common units, 100,746,988 and 98,620,333 held by the general partner and 2,025,287 and 2,077,193 held by common limited partners issued and outstanding, respectively (Note 8)	3,876,142	3,773,941
Noncontrolling interests in consolidated property partnerships and subsidiaries (Note 1)	198,777	186,375
Total capital	4,074,919	3,960,316
TOTAL LIABILITIES AND EQUITY (CAPITAL)	$ 7,562,236	$ 6,802,838