Leases (Tables)

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Leases [Abstract]

Lease, Cost [Table Text Block]

The components of lease expense during the year ended December 31, 2019 were as follows:

	Year Ended December 31, 2019
	(Dollars in millions)
Operating lease cost:
Operating leases	$	43.3
Short-term leases	49.7
Variable leases	19.1
Sublease income	(2.6		)
Total operating lease cost	$	109.5
Finance lease cost:
Amortization of right-of-use assets	$	15.3
Interest on lease liabilities	1.5
Total finance lease cost	$	16.8

Schedule of Supplemental Balance Sheet Information Related to Leases [Table Text Block]

Supplemental balance sheet information related to leases at December 31, 2019 was as follows:

	December 31, 2019
	(Dollars in millions)
Operating leases:
Operating lease right-of-use assets	$	82.4
Accounts payable and accrued expenses	$	29.6
Operating lease liabilities, less current portion	52.8
Total operating lease liabilities	$	82.4
Finance leases:
Property, plant, equipment and mine development	$	89.6
Accumulated depreciation	(45.9		)
Property, plant, equipment and mine development, net	$	43.7
Current portion of long-term debt	$	14.3
Long-term debt, less current portion	0.9
Total finance lease liabilities	$	15.2
Weighted average remaining lease term (years)
Operating leases	3.8
Finance leases	0.6
Weighted average discount rate
Operating leases	7.3		%
Finance leases	6.0		%

Schedule of Supplemental Cash Flow Information Related to Leases [Table Text Block]

Supplemental cash flow information related to leases during the year ended December 31, 2019 was as follows:

	Year Ended December 31, 2019
	(Dollars in millions)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$	51.0
Operating cash flows for finance leases	1.5
Financing cash flows for finance leases	29.6
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	16.6
Finance leases	1.6

Schedule of Maturities of Operating and Finance Lease Liabilities [Table Text Block]

The Company's leases have remaining lease terms of 1 year to 11.3 years, some of which include options to extend the terms deemed reasonably certain of exercise. Maturities of lease liabilities were as follows:

Period Ending December 31,	Operating Leases			Finance Leases
	(Dollars in millions)
2020	$	33.7		$	14.5
2021	23.1			0.6
2022	14.1			0.2
2023	12.2			0.1
2024	4.8			—
2025 and thereafter	7.2			—
Total lease payments	95.1			15.4
Less imputed interest	(12.7		)	(0.2		)
Total lease liabilities	$	82.4		$	15.2

Leases And Royalty Future Minimum Payments [Table Text Block]

Future minimum lease and royalty payments as of December 31, 2018 were as follows:

	Capital Leases		Operating Leases		Coal Lease and Royalty Obligations
Year Ending December 31,
	(Dollars in millions)
2019	$	28.2	$	47.6	$	5.4
2020	8.0		27.6		5.5
2021	0.4		15.9		5.6
2022	0.4		11.8		5.4
2023	0.5		12.1		5.5
2024 and thereafter	8.8		12.1		36.2
Total minimum lease payments	46.3		$	127.1	$	63.6
Less interest	6.3
Present value of minimum capital lease payments	$	40.0