Leases (Tables)

9 Months Ended

Sep. 30, 2020

The following tables provide information related to our lease costs (dollars in thousands):


	Three Months Ended September 30, 2020						Three Months Ended September 30, 2019
	Purchased Power Lease Contracts		Land, Property & Equipment Leases		Total		Purchased Power Lease Contracts		Land, Property & Equipment Leases		Total
Operating lease cost	$	51,662	$	4,655	$	56,317	$	21,095	$	4,581	$	25,676
Variable lease cost	40,658		232		40,890		36,917		183		37,100
Short-term lease cost	—		1,038		1,038		—		812		812
Total lease cost	$	92,320	$	5,925	$	98,245	$	58,012	$	5,576	$	63,588


	Nine Months Ended September 30, 2020						Nine Months Ended September 30, 2019
	Purchased Power Lease Contracts		Land, Property & Equipment Leases		Total		Purchased Power Lease Contracts		Land, Property & Equipment Leases		Total
Operating lease cost	$	68,883	$	13,959	$	82,842	$	35,159	$	13,343	$	48,502
Variable lease cost	102,052		730		102,782		95,736		543		96,279
Short-term lease cost	—		2,824		2,824		—		3,477		3,477
Total lease cost	$	170,935	$	17,513	$	188,448	$	130,895	$	17,363	$	148,258

Schedule of future minimum payments

The following table provides information related to the maturity of our operating lease liabilities (dollars in thousands):


	September 30, 2020
Year	Purchased Power Lease Contracts		Land, Property & Equipment Leases		Total
2020 (remaining three months of 2020)	$	14,889	$	3,294	$	18,183
2021	66,658		13,402		80,060
2022	68,325		9,781		78,106
2023	70,033		7,443		77,476
2024	71,784		5,162		76,946
2025	73,578		3,457		77,035
Thereafter	36,759		36,961		73,720
Total lease commitments	402,026		79,500		481,526
Less imputed interest	15,565		18,407		33,972
Total lease liabilities	$	386,461	$	61,093	$	447,554

The following tables provide other additional information related to operating lease liabilities (dollars in thousands):


	Nine Months Ended September 30, 2020		Nine Months Ended September 30, 2019
Cash paid for amounts included in the measurement of lease liabilities - operating cash flows:	$	56,896	$	51,980
Right-of-use operating lease assets obtained in exchange for operating lease liabilities	436,587		8,759


	September 30, 2020		December 31, 2019
Weighted average remaining lease term	7 years		13 years
Weighted average discount rate (a)	1.69	%	3.71	%

(a) Most of our lease agreements do not contain an implicit rate that is readily determinable. For these agreements we use our incremental borrowing rate to measure the present value of lease liabilities. We determine our incremental borrowing rate at lease commencement based on the rate of interest that we would have to pay to borrow, on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment. We use the implicit rate when it is readily determinable.