Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal From time to time, we are party to various lawsuits, claims and legal proceedings that arise in the ordinary course of business. We are not currently a party to any legal proceedings that we believe would reasonably be expected to have a material adverse effect on our business, financial condition or results of operations. Environmental We will generally perform environmental site assessments at properties we are considering acquiring. After the acquisition of such properties, we continue to monitor the properties for the presence of hazardous or toxic substances. From time to time, we acquire properties with known adverse environmental conditions. If at the time of acquisition, losses associated with environmental remediation obligations are probable and can be reasonably estimated, we record a liability. On February 25, 2014, we acquired the property located at West 228th Street. Before purchasing the property during the due diligence phase, we engaged a third-party environmental consultant to perform various environmental site assessments to determine the presence of any environmental contaminants that might warrant remediation efforts. Based on their investigation, they determined that hazardous substances existed at the property and that additional assessment and remediation work would likely be required to satisfy regulatory requirements. The total remediation costs were estimated to be $1.3 million, which includes remediation, processing and oversight costs. To address the estimated costs associated with the environmental issues at the West 228th Street property, we entered into an Environmental Holdback Escrow Agreement (the “Holdback Agreement”) with the former owner, whereby $1.4 million was placed into an escrow account to be used to pay remediation costs. To fund the $1.4 million, the escrow holder withheld $1.3 million of the purchase price, which would have otherwise been paid to the seller at closing, and the Company funded an additional $0.1 million. According to the Holdback Agreement, the seller has no liability or responsibility to pay for remediation costs in excess of $1.3 million. As of September 30, 2020 and December 31, 2019, we had a $0.5 million and $0.6 million contingent liability recorded in our consolidated balance sheets included in the line item “Accounts payable and accrued expenses,” reflecting the estimated remaining cost to remediate environmental liabilities at West 228th Street that existed prior to the acquisition date. As of September 30, 2020 and December 31, 2019, we also had a $0.5 million and $0.6 million corresponding indemnification asset recorded in our consolidated balance sheets included in the line item “Other assets,” reflecting the estimated costs we expect the former owner to cover pursuant to the Holdback Agreement. We expect that the resolution of the environmental matters relating to the above will not have a material impact on our consolidated financial condition, results of operations or cash flows. However, we cannot assure you that we have identified all environmental liabilities at our properties, that all necessary remediation actions have been or will be undertaken at our properties or that we will be indemnified, in full or at all, in the event that such environmental liabilities arise. Furthermore, we cannot assure you that future changes to environmental laws or regulations and their application will not give rise to loss contingencies for future environmental remediation. Tenant and Construction Related Commitments As of September 30, 2020, we had commitments of approximately $33.4 million for tenant improvement and construction work under the terms of leases with certain of our tenants and contractual agreements with our construction vendors. Concentrations of Credit Risk We have deposited cash with financial institutions that are insured by the Federal Deposit Insurance Corporation up to $250,000 per institution. Although we have deposits at institutions in excess of federally insured limits as of September 30, 2020, we do not believe we are exposed to significant credit risk due to the financial position of the institutions in which those deposits are held. Concentration of Properties in Southern California As of September 30, 2020, all of our properties are located in the Southern California infill markets. The ability of the tenants to honor the terms of their respective leases is dependent upon the economic, regulatory and social factors affecting the markets in which the tenants operate and other conditions, including the impact of the outbreak of COVID-19, which was declared a pandemic in March 2020 by the World Health Organization, and related state and local government reactions. All of our properties are concentrated in Southern California. The State of California and certain municipalities, including where we own properties, reacted to the COVID-19 pandemic early on by instituting quarantines, restrictions on travel, “shelter in place” rules, restrictions on types of business that may continue to operate and/or restrictions on types of construction projects that may continue as well as moratoriums on commercial tenant evictions and provisions enabling some commercial tenants to defer rent. We cannot predict when restrictions currently in place will expire, if additional restrictions will be added, or whether restrictions previously lifted will be reimplemented as infection rates fluctuate. Additionally, in March 2020, the Governor of California issued Executive Order N-28-20, authorizing local municipalities to impose limitations on commercial evictions for nonpayment of rent for tenants impacted by COVID-19. In response to this Executive Order, most municipalities in Southern California, in turn, mandated a moratorium on all commercial evictions and gave tenants impacted by COVID-19 the unilateral right to defer rent while the emergency orders are in effect, with repayment generally within three to six months after the end of the local emergency. Only a small number of municipalities have allowed their local orders to expire or modified the orders to exclude some tenants (based on the tenant’s number of employees, being a publicly traded company or multinational company, or other characteristics), and in many of the local municipalities in which we operate, the expiration of the eviction restrictions and rent deferment rights is tied to the Governor’s Executive Order N-28-20, now extended until March 31, 2021, while in other municipalities the restrictions expire when the local emergency is lifted. We cannot currently predict whether or not these restrictions may be extended or for how long. Some of the orders, including Executive Order N-28-20, have been extended multiple times. A number of our tenants have taken advantage of the relief provided by the local government mandates authorizing deferral of rent, irrespective of certain such tenants’ actual ability to pay such rent, and we are currently unable to predict the impact that the COVID-19 pandemic will have on our tenants or the number of tenants that will take advantage of the relief provided by the local government mandates authorizing the deferral of rent. See Note 2 “Summary of Significant Accounting Policies—COVID-19 Lease Concessions” for information related to rent relief agreements executed during the three and nine months ended September 30, 2020. Tenant Concentration During the nine months ended September 30, 2020, no single tenant accounted for more than 5% of our total consolidated rental income.