CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Cash Flows from Operating Activities
Net income (loss)	$ 56.1	$ 24.5
Adjustments to reconcile net income (loss) to net cash (used in) operating activities:
Depreciation and amortization	5.4	5.2
Deferred tax assets	15.5	6.3
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	0.0	(16.6)
Equity related compensation	4.7	0.7
Revaluation of inventory borrowing	3.6	1.8
Gain (Loss) on Extinguishment of Debt	(11.8)	0.0
Other Operating Activities, Cash Flow Statement	1.3	0.1
Changes in operating assets and liabilities:
Accounts receivable – (increase) decrease	48.6	14.9
Inventories – (increase) decrease	(221.5)	80.8
Increase Decrease in Inventories Owed to Suppliers	111.2	(83.2)
Increase (Decrease) in Prepaid Expenses, Other	1.3	0.0
Accounts payable and other liabilities – increase (decrease)	(6.1)	(7.6)
Payables under SWU purchase agreements – increase (decrease)	97.6	(4.2)
Deferred revenue, net of deferred costs – increase (decrease)	(12.6)	(5.0)
Pension and postretirement liabilities - increase (decrease)	(3.9)	(5.2)
Other, net	(0.1)	(0.2)
Net Cash (Used in) Operating Activities	89.3	12.3
Cash Flows Provided by Investing Activities
Capital expenditures	(5.7)	(2.4)
Net Cash Provided by (Used in) Investing Activities	(5.7)	(2.4)
Cash Flows Used in Financing Activities
Proceeds from the sale of common stock, net	139.9	19.0
Payment of interest classified as debt	(3.5)	(3.1)
Payment, Tax Withholding, Share-based Payment Arrangement	(2.5)	(0.3)
Repayments of Convertible Debt	(74.3)	0.0
Exercise of stock options	0.0	0.4
Net Cash (Used in) Financing Activities	59.6	16.0
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations	(0.2)	(0.1)
Decrease in cash, cash equivalents and restricted cash	143.0	25.8
Cash, cash equivalents and restricted cash, start of period	704.0	233.8
Cash, cash equivalents and restricted cash, end of period	847.0	259.6
Income Taxes Paid, Net	0.3	0.6
Interest Paid, Excluding Capitalized Interest, Operating Activities	4.4	0.0
Property, plant and equipment included in accounts payable and accrued liabilities [Member]
Supplemental Cash Flow Information:
Other Significant Noncash Transaction, Value of Consideration Given	(0.6)	(0.5)
Equity issuance costs included in accounts payable and accrued liabilities [Member]
Supplemental Cash Flow Information:
Other Significant Noncash Transaction, Value of Consideration Given	(0.1)	(0.1)
Shares withheld for employee taxes [Member]
Supplemental Cash Flow Information:
Other Significant Noncash Transaction, Value of Consideration Given	0.0	(0.1)
Adjustment to Right of Use Lease due to Modification [Domain]
Supplemental Cash Flow Information:
Other Significant Noncash Transaction, Value of Consideration Given	$ (1.3)	$ 0.0