Our leased assets include offices and studios, transmitter locations, antenna sites, towers, tower sites, and land. Our lease portfolio has terms remaining from less than up to twenty years. Many of these leases contain options under which we can extend the term from five to twenty years, the exercise of which is at our sole discretion. Renewal options are excluded from our calculation of lease liabilities unless we are reasonably assured to exercise the renewal option. Our lease agreements do not contain residual value guarantees or material restrictive covenants. We lease certain properties from our principal stockholders or from trusts and partnerships created for the benefit of the principal stockholders and their families. These leases are designated as Related Party leases in the details provided. We are obligated to pay taxes, insurance and common area maintenance charges under a majority of our lease agreements.

Operating leases are reflected on our balance sheet within operating lease ROU assets and the related current and operating lease liabilities. ROU assets represent the right to use an underlying asset for the lease term, and lease liabilities represent the obligation to make lease payments arising from lease agreement. Operating lease ROU assets and liabilities are recognized at the commencement date, or the date on which the lessor makes the underlying asset available for use, based upon the present value of the lease payments over the respective lease term. Lease expense is recognized on a straight-line basis over the lease term, subject to any changes in the lease or expectation regarding the lease terms. Variable lease costs, such as common area maintenance, property taxes and insurance, are expensed as incurred.

Due to the adverse economic impact of the pandemic, we began negotiating with landlords in early 2020 to obtain rent concessions to improve our short-term liquidity. In some instances, the renegotiations have led to agreements with landlords for rent abatements or rental deferrals. In accordance with the FASB’s recent Staff Q&A regarding rent concessions related to the effects of the pandemic, we will not apply the lease modification guidance under ASC 842 to rent concessions that result in the total payments required under the modified contract that are substantially the same as or less than total payments required by the original contract. If other terms of the lease are changed or renegotiated in connection with the concession process, then the changes will be treated as a modification in accordance with ASC 842.

The adoption of ASC 842 resulted in recording a transitional adjustment to operating lease ROU assets and operating lease liabilities of $65.0 million and $74.4 million, respectively. The difference between the operating lease ROU assets and operating lease liabilities at transition represented existing deferred rent expense and prepaid rent that was derecognized upon adoption. During the year ended December 31, 2020, we recorded additional ROU assets and corresponding lease liabilities of $4.2 million.

Future minimum lease payments under leases that had initial or remaining lease terms in excess of year as of December 31, 2020, are as follows: