Certain of the Company’s investments in real estate are subject to ground leases. The Company’s ground leases are classified as either operating leases or financing leases based on the characteristics of each lease. As of September 30, 2020, the Company had 15 ground leases classified as operating and two ground leases classified as financing. Each of the Company’s ground leases were acquired as part of the acquisition of real estate and no incremental costs were incurred for such ground leases. The Company’s ground leases are non-cancelable, and two of the Company’s operating leases contain renewal options for additional 99 and 10 year terms.

The following table presents the future lease payments due under the Company’s ground leases as of September 30, 2020 ($ in thousands):

	Operating Leases			Financing Leases
2020 (remaining)	$	1,039		$	759
2021		3,982			3,081
2022		4,093			3,174
2023		4,132			3,269
2024		4,183			3,367
2025		4,423			3,468
Thereafter		599,932			327,054
Total undiscounted future lease payments		621,784			344,172
Difference between undiscounted cash flows and discounted cash flows		(537,130	)		(286,688	)
Total lease liability	$	84,654		$	57,484

The Company utilized its incremental borrowing rate, which was between 5% and 7%, to determine its lease liabilities. As of September 30, 2020, the weighted average remaining lease term of the Company’s operating leases and financing leases was 56 years and 76 years, respectively.

Payments under the Company’s ground leases primarily contain fixed payment components that may include periodic increases fixed to an index or periodic fixed percentage escalations. One of the Company’s ground leases contains a variable component based on a percentage of revenue.

The following table summarizes the fixed and variable components of the Company’s operating leases ($ in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Fixed ground rent expense	$	1,000	$	390	$	3,026	$	1,108
Variable ground rent expense		—		—		18		21
Total cash portion of ground rent expense		1,000		390		3,044		1,129
Non-cash ground rent expense		1,656		1,091		5,090		3,275
Total operating lease costs	$	2,656	$	1,481	$	8,134	$	4,404

The following table summarizes the fixed and variable components of the Company’s financing leases ($ in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Interest on lease liabilities	$	759	$	737	$	2,233	$	1,491
Amortization of right-of-use assets		239		243		748		504
Total financing lease costs	$	998	$	980	$	2,981	$	1,995

The Company’s rental revenue primarily consists of rent earned from operating leases at the Company’s multifamily, industrial, retail, office, net lease and other properties. Leases at the Company’s industrial, retail, and office properties generally include a fixed base rent and certain leases also contain a variable component. The variable component of the Company’s operating leases at its industrial, retail, and office properties primarily consist of the reimbursement of operating expenses such as real estate taxes, insurance, and common area maintenance costs. Rental revenue earned from leases at the Company’s multifamily properties primarily consist of a fixed base rent and certain leases contain a variable component that allows for the pass-through of certain operating expenses such as utilities. During the nine months ended September 30, 2020, the Company changed its presentation for the payment of leasing commissions in the Condensed Consolidated Statement of Cash Flows to investing activities from operating activities to better align with how the Company assesses its overall investments in its properties. The Company does not believe the change in presentation to be material as the Company had $19.7 million of leasing commissions during the nine months ended September 30, 2020.

Rental revenue from the Company’s lease at the Bellagio consists of a fixed annual rent that escalates annually throughout the term of the lease and the tenant is generally responsible for all property-related expenses, including taxes, insurance and maintenance. The Company assessed the classification of the Bellagio lease and determined the lease was an operating lease. The Company’s assessment included the consideration of the present value of the lease payments over the lease term and the residual value of the assets under the lease.

Leases at the Company’s industrial, retail, office, and net lease properties are generally longer term and may contain extension and termination options at the lessee’s election. Leases at the Company’s multifamily and other properties are short term in nature, generally not greater than 12 months in length.

The following table details the components of operating lease income from leases in which the Company is the lessor ($ in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Fixed lease payments	$	509,188	$	262,043	$	1,492,519	$	674,780
Variable lease payments		52,865		28,410		155,346		75,542
Rental revenue	$	562,053	$	290,453	$	1,647,865	$	750,322

The Company increased the reserve for bad debt expense in the amount of $10.9 million and $30.2 million for the three and nine months ended September 30, 2020, respectively, primarily as a result of COVID-19. The bad debt reserve represents the amount of rental revenue the Company anticipates it will not be able to collect from its tenants and is included in Rental Revenue on the Company’s Condensed Consolidated Statements of Operations.

The following table presents the undiscounted future minimum rents the Company expects to receive for its industrial, net lease, retail and office properties as of September 30, 2020 ($ in thousands). Leases at the Company’s multifamily and self-storage properties are short term, generally 12 months or less, and are therefore not included.

Year	Future Minimum Rents
2020 (remaining)	$	233,705
2021		903,539
2022		818,373
2023		714,351
2024		624,682
2025		556,912
Thereafter		9,102,733
Total	$	12,954,295