Supplemental Balance Sheet Information (Tables)

12 Months Ended

Dec. 31, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Supplemental Balance Sheet Information

	As of December 31,
	2024			2023
	(In millions of dollars)
Trade Receivables, Net
Billed trade receivables	$	320.5		$	325.8
Allowance for doubtful receivables		(0.8	)		(0.6	)
Trade receivables, net	$	319.7		$	325.2
Inventories
Finished products	$	103.7		$	89.3
Work-in-process		193.3			210.8
Raw materials		192.8			161.5
Operating supplies		14.1			15.6
Inventories	$	503.9		$	477.2
Property, Plant and Equipment, Net
Land and improvements	$	37.2		$	38.0
Buildings and leasehold improvements		256.3			238.4
Machinery and equipment 1		1,337.4			1,265.3
Construction in progress		297.5			173.7
Property, plant and equipment, gross		1,928.4			1,715.4
Accumulated depreciation and amortization		(767.5	)		(663.7	)
Land held for sale		0.3			0.4
Property, plant and equipment, net	$	1,161.2		$	1,052.1
Other Assets
Assets to be conveyed associated with Warrick acquisition 1	$	18.3		$	56.8
Restricted cash – Note 16		19.5			18.3
Long-term replacement parts		18.3			16.7
Other		22.5			25.9
Other assets	$	78.6		$	117.7
.
Other Accrued Liabilities
Uncleared cash disbursements	$	24.5		$	15.7
Accrued income taxes and other taxes payable		11.2			9.5
Accrued annual contribution to Salaried VEBA – Note 5		0.7			1.1
Accrued interest		9.9			9.9
Short-term environmental accrual – Note 10		0.7			2.8
Current operating lease liabilities – Note 3		6.3			8.0
Current finance lease liabilities – Note 3		2.4			2.1
Current deferred compensation plan liabilities - Note 5		6.7			0.4
Other – Note 8		17.0			14.8
Other accrued liabilities	$	79.4		$	64.3
Long-Term Liabilities
Workers' compensation accrual	$	26.8		$	29.9
Long-term environmental accrual – Note 10		17.7			14.2
Other long-term liabilities		39.5			37.6
Long-term liabilities	$	84.0		$	81.7

1.During the year ended December 31, 2024, $38.5 million of certain assets associated with our acquisition of Warrick were conveyed to us and placed in service. At December 31, 2024, such assets are presented within Machinery and equipment.