Derivatives and Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Classification and amounts of pre-tax gains and losses related to the Company's non coal-trading hedges

The tables below show the classification and amounts of pre-tax gains and losses related to the Company’s Corporate Hedging derivatives:

			Successor
			Three Months Ended September 30, 2018
Financial Instrument	Income Statement Classification		Total loss recognized in income			Loss realized in income on derivatives			Unrealized gain recognized in income on non-designated derivatives
		(Dollars in millions)
Foreign currency option contracts	Operating costs and expenses		$	(1.5	)	$	(1.8	)	$	0.3
Total			$	(1.5	)	$	(1.8	)	$	0.3

			Successor
			Three Months Ended September 30, 2017
Financial Instrument	Income Statement Classification		Total gain recognized in income		Gain realized in income on derivatives		Unrealized loss recognized in income on non-designated derivatives
		(Dollars in millions)
Foreign currency option contracts	Operating costs and expenses		$	5.6	$	7.3	$	(1.7	)
Total			$	5.6	$	7.3	$	(1.7	)

			Successor
			Nine Months Ended September 30, 2018
Financial Instrument	Income Statement Classification		Total loss recognized in income			Loss realized in income on derivatives			Unrealized loss recognized in income on non-designated derivatives
		(Dollars in millions)
Foreign currency option contracts	Operating costs and expenses		$	(7.9	)	$	(6.5	)	$	(1.4	)
Total			$	(7.9	)	$	(6.5	)	$	(1.4	)

			Successor
			April 2 through September 30, 2017
Financial Instrument	Income Statement Classification		Total gain recognized in income		Gain realized in income on derivatives		Unrealized gain recognized in income on non-designated derivatives
		(Dollars in millions)
Foreign currency option contracts	Operating costs and expenses		$	8.5	$	7.0	$	1.5
Total			$	8.5	$	7.0	$	1.5

			Predecessor
			January 1 through April 1, 2017
Financial Instrument	Income Statement Classification		Total loss recognized in income			Loss reclassified from other comprehensive loss into income
		(Dollars in millions)
Commodity swap contracts	Operating costs and expenses		$	(11.0	)	$	(11.0	)
Foreign currency option contracts	Operating costs and expenses		(16.6		)	(16.6		)
Total			$	(27.6	)	$	(27.6	)

Fair Value, Assets Measured on Recurring Basis

The following tables set forth the hierarchy of the Company’s net financial asset positions for which fair value is measured on a recurring basis:

	September 30, 2018
	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Equity securities	$	—	$	—	$	10.0	$	10.0
Foreign currency contracts	—		0.2		—		0.2
Total net financial assets	$	—	$	0.2	$	10.0	$	10.2
	December 31, 2017
	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Foreign currency contracts	$	—	$	4.2	$	—	$	4.2
Total net financial assets	$	—	$	4.2	$	—	$	4.2

Carrying amounts and estimated fair values of the Company's debt

The carrying amounts and estimated fair values of the Company’s current and long-term debt as of September 30, 2018 and December 31, 2017 are summarized as follows:

	September 30, 2018				December 31, 2017
	Carrying Amount		Estimated Fair Value		Carrying Amount		Estimated Fair Value
	(Dollars in millions)
Current and Long-term debt	$	1,376.2	$	1,451.0	$	1,460.8	$	1,547.4