Consolidated Statements of Capital (KILROY REALTY, L.P.) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 41,794	$ 40,971
Non-cash amortization of share-based compensation	8,817	5,094
Exercise of stock options	0	0
Distributions to noncontrolling interests in consolidated property partnerships	(6,309)	(2,177)
Accounting Standards Update 2016-02 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative adjustment			$ (3,146)
Noncontrolling Interests [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	4,891	4,725
Distributions to noncontrolling interests in consolidated property partnerships	(6,309)	(2,177)
Kilroy Realty L.P. [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	4,201,261	3,960,316
Net income	41,794	40,971
Issuance of share-based compensation awards	2,210	1,864
Non-cash amortization of share-based compensation	8,817	5,094
Exercise of stock options	0	0
Repurchase of common units, stock options and restricted stock units	(12,130)	(13,642)
Distributions to noncontrolling interests in consolidated property partnerships	(6,309)	(2,177)
Distributions declared per common unit ($0.455 and $0.425 per unit for the three months ended March 31, 2019 and 2018, respectively)	(49,315)	(44,954)
Ending balance	$ 4,183,182	$ 3,947,472
Kilroy Realty L.P. [Member] \| Accounting Standards Update 2016-02 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative adjustment			(3,146)
Kilroy Realty L.P. [Member] \| Partners Capital Common Unit [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in units)	102,772,275	100,697,526
Beginning balance	$ 4,003,700	$ 3,773,941
Net income	37,508	36,893
Issuance of share-based compensation awards	2,210	1,864
Non-cash amortization of share-based compensation	$ 8,817	$ 5,094
Settlement of restricted stock units (in units)	393,240	405,067
Exercise of stock options	$ 0	$ 0
Repurchase of common units, stock options and restricted stock units (in units)	(175,204)	(192,195)
Repurchase of common units, stock options and restricted stock units	$ (12,130)	$ (13,642)
Distributions declared per common unit ($0.455 and $0.425 per unit for the three months ended March 31, 2019 and 2018, respectively)	$ (49,315)	$ (44,954)
Ending balance (in units)	102,990,311	100,910,398
Ending balance	$ 3,987,644	$ 3,759,196
Kilroy Realty L.P. [Member] \| Partners Capital Common Unit [Member] \| Accounting Standards Update 2016-02 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative adjustment			$ (3,146)
Kilroy Realty L.P. [Member] \| Noncontrolling Interests [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	197,561	186,375
Net income	4,286	4,078
Distributions to noncontrolling interests in consolidated property partnerships	(6,309)	(2,177)
Ending balance	$ 195,538	$ 188,276

Amount of increase to additional paid-in capital (APIC) from recognition of equity-based compensation.

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