Leases (Tables)

6 Months Ended

Jun. 30, 2019

The following tables provide other additional information related to operating lease liabilities:



	June 30, 2019
Weighted average remaining lease term	8 years
Weighted average discount rate (a)	3.84	%

(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.



	Six Months Ended June 30, 2019
Cash paid for amounts included in the measurement of lease liabilities - operating cash flows (dollars in thousands):	$	11,987

The following tables provide information related to our lease costs for the three and six months ended June 30, 2019 (dollars in thousands):



	Three Months Ended June 30, 2019
	Purchased Power Lease Contracts		Land, Property & Equipment Leases		Total
Operating lease cost	$	14,063	$	4,414	$	18,477
Variable lease cost	41,529		360		41,889
Short-term lease cost	—		1,812		1,812
Total lease cost	$	55,592	$	6,586	$	62,178



	Six Months Ended June 30, 2019
	Purchased Power Lease Contracts		Land, Property & Equipment Leases		Total
Operating lease cost	$	14,063	$	8,762	$	22,825
Variable lease cost	58,820		360		59,180
Short-term lease cost	—		2,665		2,665
Total lease cost	$	72,883	$	11,787	$	84,670

Schedule of future minimum payments

The following table provides information related to the maturity of our operating lease liabilities at June 30, 2019 (dollars in thousands):



	June 30, 2019
Year	Purchased Power Lease Contracts		Land, Property & Equipment Leases		Total
2019 (remaining six months of 2019)	$	49,051	$	7,335	$	56,386
2020	—		12,868		12,868
2021	—		10,029		10,029
2022	—		6,988		6,988
2023	—		5,838		5,838
2024	—		3,691		3,691
Thereafter	—		38,506		38,506
Total lease commitments	49,051		85,255		134,306
Less imputed interest	294		20,411		20,705
Total lease liabilities	$	48,757	$	64,844	$	113,601

We recognize lease assets and liabilities upon lease commencement. At June 30, 2019, we have additional lease arrangements that have been executed, but have not yet commenced. These arrangements primarily relate to purchased power lease contracts. These leases have commencement dates beginning in June 2020 with terms ending through October 2027. We expect the total fixed consideration paid for these arrangements, which includes both lease and nonlease payments, will approximate $705 million over the term of the arrangements.

The following table provides information related to estimated future minimum operating lease payments at December 31, 2018 (dollars in thousands):



	December 31, 2018
Year	Purchased Power Lease Contracts		Land, Property & Equipment Leases		Total
2019	$	54,499	$	13,747	$	68,246
2020	—		12,428		12,428
2021	—		9,478		9,478
2022	—		6,513		6,513
2023	—		5,359		5,359
Thereafter	—		42,236		42,236
Total future lease commitments	$	54,499	$	89,761	$	144,260