We have entered into ground leases for portions of the land at Springfield Town Center and Plymouth Meeting Mall. We have also entered into an office lease for our headquarters location, as well as vehicle, solar panel and equipment leases as a lessee. The initial terms of these agreements generally range from three to 40 years, with certain agreements containing extension options for up to an additional 60 years. As of September 30, 2020, we included only those renewal options we were reasonably certain of exercising. Upon lease execution, the Company measures a liability for the present value of future lease payments over the noncancelable period of the lease and any renewal option period we are reasonably certain of exercising. Certain agreements require that we pay a portion of reimbursable expenses such as CAM, utilities, insurance and real estate taxes. These payments are not included in the calculation of the lease liability and are presented as variable lease costs.

We applied judgments related to the determination of the discount rates used to calculate the lease liability upon adoption of ASC 842 at January 1, 2019. In order to calculate our incremental borrowing rate under ASC 842, we utilized judgments and estimates regarding our implied credit rating using market data and made other adjustments to determine an appropriate incremental borrowing rate as of January 1, 2019.

The following table presents additional information pertaining to the Company’s leases:

	Three Months Ended September 30, 2020								Nine Months Ended September 30, 2020
(in thousands of dollars)	Solar Panel Leases		Ground Leases		Office, equipment, and vehicle leases		Total		Solar Panel Leases		Ground Leases		Office, equipment, and vehicle leases		Total
Finance lease cost:
Amortization of right-of-use assets	$	209	$	—	$	—	$	209	$	621	$	—	$	—	$	621
Interest on lease liabilities		68		—		—		68		215		—		—		215
Operating lease costs		—		436		333		769		—		1,309		1,008		2,317
Variable lease costs		—		44		60		104		—		129		142		271
Total lease costs	$	277	$	480	$	393	$	1,150	$	836	$	1,438	$	1,150	$	3,424

Other information related to leases as of and for the nine months ended September 30, 2020 is as follows:

(in thousands of dollars)
Cash paid for the amounts included in the measurement of lease liabilities
Operating cash flows used for finance leases	$	208
Operating cash flows used for operating leases	$	1,552
Financing cash flows used for finance leases	$	526
Weighted average remaining lease term-finance leases (months)		89
Weighted average remaining lease term-operating leases (months)		300
Weighted average discount rate-finance leases		4.35	%
Weighted average discount rate-operating leases		6.43	%

Future payments against lease liabilities as of September 30, 2020 are as follows:

(in thousands of dollars)	Finance leases			Operating leases			Total
October 1 to December 31, 2020	$	248		$	563		$	811
2021		990			2,573			3,563
2022		988			2,558			3,546
2023		983			2,514			3,497
2024		949			2,428			3,377
Thereafter		3,000			53,545			56,545
Total undiscounted lease payments		7,158			64,181			71,339
Less imputed interest		(1,048	)		(33,969	)		(35,017	)
Total lease liabilities	$	6,110		$	30,212		$	36,322

Future payments against lease liabilities as of December 31, 2019 were as follows:

(in thousands of dollars)	Finance leases			Operating leases			Total
Year ending December 31,
2020	$	925		$	2,237		$	3,162
2021		925			2,730			3,655
2022		925			2,538			3,463
2023		925			2,485			3,410
2024		925			2,373			3,298
Thereafter		2,999			46,853			49,852
Total undiscounted lease payments		7,624			59,216			66,840
Less imputed interest		(1,242	)		(28,965	)		(30,207	)
Total lease liabilities	$	6,382		$	30,251		$	36,633

As of September 30, 2020, the fixed contractual lease payments, including minimum rents and fixed CAM amounts, to be received over the next five years pursuant to the terms of noncancelable operating leases with initial terms greater than one year are included in the table below. The amounts presented assume that no leases are renewed and no renewal options are exercised, and do not include any rent deferral arrangements executed during the nine months ended September 30, 2020. Additionally, the table does not include variable lease payments that may be received under certain leases for percentage rents or the reimbursement of operating costs, such as common area expenses, utilities, insurance and real estate taxes. These variable lease payments are recognized in the period when the applicable expenditures are incurred or, in the case of percentage rents, when the sales data is made available.