The Company has leases, primarily for equipment, railcars, fleet vehicles, office space, land and information technology equipment and software. The Company’s leases have remaining lease terms of one year to 54 years, some of which may include options to extend the leases for up to 30 years, and some of which may include options to terminate the leases within one year.

Certain of the Company’s lease agreements include payments based upon variable rates, including but not limited to hours used, tonnage processed and factors related to indices. The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants.

	Three Months Ended		Nine Months Ended
	September 30, 2019		September 30, 2019
	(Dollars in Thousands)
Operating lease cost	$	19,627	$	59,024
Finance lease cost:
Amortization of right-of-use assets		755		2,325
Interest on lease liabilities		126		412
Variable lease cost		4,972		15,738
Short-term lease cost		8,897		25,157
Total lease cost	$	34,377	$	102,656

The balance sheet classifications of operating and finance leases are as follows:

	September 30, 2019
	(Dollars in Thousands)
Operating Leases:
Operating lease right-of-use assets	$	484,853

Current operating lease liabilities	$	51,751
Noncurrent operating lease liabilities		436,698
Total operating lease liabilities	$	488,449

Finance Leases:
Property, plant and equipment	$	10,800
Accumulated depreciation		(2,325	)
Property, plant and equipment, net	$	8,475

Other current liabilities	$	3,058
Other noncurrent liabilities		6,473
Total finance lease liabilities	$	9,531

The estimated incremental borrowing rate range used was 3.5% to 5.5%. Weighted-average remaining lease terms and discount rates are as follows:

	September 30, 2019
Weighted-average remaining lease term (years):
Operating leases		14.7
Finance leases		8.7

Weighted-average discount rate:
Operating leases		4.3	%
Finance leases		5.2	%

	Operating			Finance
	Leases			Leases
	(Dollars in Thousands)
2019	$	18,253		$	948
2020		68,838			3,196
2021		56,568			1,951
2022		51,600			1,094
2023		47,934			779
Thereafter		434,190			4,177
Total lease payments		677,383			12,145
Less: imputed interest		(188,934	)		(2,614	)
Present value of lease payments		488,449			9,531
Less: current lease obligations		(51,751	)		(3,058	)
Total long-term lease obligations	$	436,698		$	6,473

The following tables present supplemental cash flow and non-cash information related to leases:

	Three Months Ended		Nine Months Ended ⁽¹⁾
	September 30, 2019		September 30, 2019
	(Dollars in Thousands)
Right-of-use assets obtained in exchange for new operating lease liabilities	$	11,034	$	36,369
Right-of-use assets obtained in exchange for new finance lease liabilities	$	—	$	217

Leases entered into but not yet commenced for the quarter ended September 30, 2019 were immaterial.

Total lease expense for operating leases was $122.5 million for the year ended December 31, 2018. Total royalties, principally for leased properties, were $52.5 million, for the year ended December 31, 2018. The Company also has capital lease obligations for machinery and equipment. Future minimum lease and royalty commitments for all noncancelable agreements and capital lease obligations as of December 31, 2018 were as follows:

	Capital Leases			Operating Leases		Royalty Commitments
	(Dollars in Thousands)
2019	$	3,718		$	105,955	$	14,614
2020		2,695			70,478		11,364
2021		1,735			60,382		10,335
2022		1,004			57,531		9,545
2023		713			56,511		8,109
Thereafter		3,893			318,147		65,981
Total		13,758		$	669,004	$	119,948
Less: imputed interest		(2,879	)
Present value of minimum lease payments		10,879
Less: current capital lease obligations		(3,249	)
Long-term capital lease obligations	$	7,630

September 30, 2019

(Dollars in Thousands)

Cash paid for amounts included in the measurement

of lease liabilities:

Operating cash flows used for operating leases

Operating cash flows used for finance leases

Financing cash flows used for finance leases