Compass Minerals International (CMP) 10-Q 8 Feb 24 2024 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Dec. 31, 2023	Feb. 02, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Dec. 31, 2023
Document Transition Report	false
Entity File Number	001-31921
Entity Registrant Name	Compass Minerals International, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	36-3972986
Entity Address, Address Line One	9900 West 109th Street
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Overland Park
Entity Address, State or Province	KS
Entity Address, Postal Zip Code	66210
City Area Code	913
Local Phone Number	344-9200
Title of 12(b) Security	Common stock, $0.01 par value
Trading Symbol	CMP
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		41,311,296
Entity Central Index Key	0001227654
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Current assets:
Cash and cash equivalents	$ 38.3	$ 38.7
Receivables, less allowance for doubtful accounts of $2.6 at December 31, 2023 and $2.3 at September 30, 2023	168.6	129.5
Inventories	392.5	392.2
Other	28.4	33.4
Total current assets	627.8	593.8
Property, plant and equipment, net	803	852.2
Intangible assets, net	119.5	120
Goodwill	97.2	96.8
Other	157.8	155.2
Total assets	1,805.3	1,818
Current liabilities:
Current portion of long-term debt	5	5
Accounts payable	85.9	116.8
Accrued salaries and wages	19.5	25.7
Income taxes payable	2.1	16.5
Accrued interest	4.4	12.9
Accrued expenses and other current liabilities	87.4	98.9
Total current liabilities	204.3	275.8
Long-term debt, net of current portion	908.7	800.3
Deferred income taxes, net	60.7	58.5
Other noncurrent liabilities	171.8	166.2
Commitments and contingencies
Stockholders’ equity:
Common stock: $0.01 par value, 200,000,000 authorized shares; 42,197,964 issued shares at December 31, 2023 and September 30, 2023	0.4	0.4
Additional paid-in capital	424.8	413.1
Treasury stock, at cost — 976,106 shares at December 31, 2023 and 1,038,168 shares at September 30, 2023	(9.3)	(8.7)
Retained earnings	135.6	217.1
Accumulated other comprehensive loss	(91.7)	(104.7)
Total stockholders’ equity	459.8	517.2
Total liabilities and stockholders’ equity	$ 1,805.3	$ 1,818

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
ASSETS
Allowance for doubtful accounts	$ 2.6	$ 2.3
Stockholders’ equity:
Common stock, par or stated value per share (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	42,197,964	42,197,964
Treasury stock, shares (in shares)	976,106	1,038,168

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Sales	$ 341.7	$ 352.4
Gross profit	70.6	70
Selling, general and administrative expenses	45.7	41.8
Loss on impairment of long-lived assets, net	74.8	0
Other operating expense	5.4	0.3
Operating (loss) earnings	(55.3)	27.9
Other (income) expense:
Interest income	(0.4)	(1.1)
Interest expense	15.8	13.9
Loss on foreign exchange	1.9	2.5
Net loss in equity investee	0	0.9
Other expense, net	0.7	0.1
(Loss) earnings before income taxes	(73.3)	11.6
Income tax expense	1.8	11.9
Net loss	$ (75.1)	$ (0.3)
Basic net loss per common share (in dollars per share)	$ (1.83)	$ (0.01)
Diluted net loss per common share (in dollars per share)	$ (1.83)	$ (0.01)
Weighted-average common shares outstanding (in thousands):
Basic (in shares)	41,205	39,751
Diluted (in shares)	41,205	39,751
Shipping and handling cost
Cost	$ 91.3	$ 107.4
Product cost
Cost	$ 179.8	$ 175

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Net earnings (loss)	$ (75.1)	$ (0.3)
Other comprehensive income (loss):
Unrealized gain from change in pension obligations, net of tax of $(0.1) and $0.0 for the three months ended December 31, 2023 and 2022, respectively	0.2	0.1
Unrealized loss on cash flow hedges, net of tax of $0.0 and $0.4 for the three months ended December 31, 2023 and 2022, respectively	(1.8)	(2.8)
Cumulative translation adjustment	14.6	11.7
Comprehensive (loss) income	$ (62.1)	$ 8.7

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Unrealized gain from change in pension obligations, tax	$ (0.1)	$ 0
Unrealized gain (loss) on cash flow hedges, tax	$ 0	$ 0.4

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance at Sep. 30, 2022	$ 256.4	$ 0.4	$ 152.1		$ 226.5	$ (115.3)
Beginning balance, treasury stock at Sep. 30, 2022				$ (7.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive (loss) income	8.7				(0.3)	9
Dividends on common stock	(6.3)				(6.3)
Shares issued for stock units, net of shares withheld for taxes	240.7		240.7
Shares issued for stock units, net of shares withheld for taxes	(0.3)			(0.3)
Stock-based compensation	10.6		10.6
Ending balance at Dec. 31, 2022	509.8	0.4	403.4		219.9	(106.3)
Ending balance , treasury stock at Dec. 31, 2022				(7.6)
Beginning balance at Sep. 30, 2023	517.2	0.4	413.1		217.1	(104.7)
Beginning balance, treasury stock at Sep. 30, 2023	(8.7)			(8.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive (loss) income	(62.1)				(75.1)	13
Dividends on common stock	(6.4)				(6.4)
Shares issued for stock units, net of shares withheld for taxes	(0.8)		(0.2)	(0.6)
Stock-based compensation	11.9		11.9
Ending balance at Dec. 31, 2023	459.8	$ 0.4	$ 424.8		$ 135.6	$ (91.7)
Ending balance , treasury stock at Dec. 31, 2023	$ (9.3)			$ (9.3)

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Statement of Stockholders' Equity [Abstract]
Cash dividends per share (in dollars per share)	$ 0.15	$ 0.15

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net earnings (loss)	$ (75.1)	$ (0.3)
Adjustments to reconcile net loss to net cash flows provided by operating activities:
Depreciation, depletion and amortization	25.5	23.9
Amortization of deferred financing costs	0.6	0.7
Stock-based compensation	11.9	10.6
Deferred income taxes	0.6	(5.4)
Unrealized foreign exchange loss	1.7	2
Loss on impairment of long-lived assets, net	74.8	0
Net loss in equity investees	0	0.9
Other, net	1.5	1
Changes in operating assets and liabilities:
Receivables	(37.4)	(34)
Inventories	8.3	5.1
Other assets	4.6	10.4
Accounts payable and accrued expenses and other current liabilities	(80.2)	(13.1)
Other liabilities	(2.4)	0.3
Net cash (used in) provided by operating activities	(65.6)	2.1
Cash flows from investing activities:
Capital expenditures	(35.3)	(19.9)
Other, net	(0.7)	(0.2)
Net cash used in investing activities	(36)	(20.1)
Cash flows from financing activities:
Proceeds from revolving credit facility borrowings	88.7	16.7
Principal payments on revolving credit facility borrowings	(17.8)	(168.2)
Proceeds from issuance of long-term debt	38.4	35.4
Principal payments on long-term debt	(1.2)	0
Net proceeds from private placement of common stock	0	240.7
Dividends paid	(6.4)	(6.3)
Shares withheld to satisfy employee tax obligations	(0.8)	(0.3)
Other, net	0	(0.3)
Net cash provided by financing activities	100.9	117.7
Effect of exchange rate changes on cash and cash equivalents	0.3	0.3
Net change in cash and cash equivalents	(0.4)	100
Cash and cash equivalents, beginning of the year	38.7	46.1
Cash and cash equivalents, end of period	38.3	146.1
Supplemental cash flow information:
Interest paid, net of amounts capitalized	23.6	18.8
Income taxes paid, net of refunds	$ 12.8	$ 2

Accounting Policies and Basis o

Accounting Policies and Basis of Presentation	3 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Accounting Policies and Basis of Presentation	Accounting Policies and Basis of Presentation: Compass Minerals International, Inc. (“CMI”), through its subsidiaries (collectively, the “Company”), is a leading global provider of essential minerals focused on safely delivering where and when it matters to help solve nature’s challenges for customers and communities. The Company’s salt products help keep roadways safe during winter weather and are used in numerous other consumer, industrial, chemical and agricultural applications. Its plant nutrition business is the leading North American producer of sulfate of potash (“SOP”), which is used in the production of specialty fertilizers for high-value crops and turf and helps improve the quality and yield of crops, while supporting sustainable agriculture. The Company’s principal products are salt, consisting of sodium chloride and magnesium chloride, and SOP. The Company’s next-generation fire retardants help to slow, stop and prevent wildfires through the use of high-performing and environmentally-friendly products. Additionally, the Company had been pursuing the development of a sustainable lithium salt resource to support the North American battery market. However, as described in Note 5 , the Company has terminated its pursuit of the lithium development. The Company’s production sites are located in the United States (“U.S.”), Canada and the United Kingdom (“U.K.”). The Company also provides records management services in the U.K. Except where otherwise noted, references to North America include only the continental U.S. and Canada, and references to the U.K. include only England, Scotland and Wales. References to “Compass Minerals,” “our,” “us” and “we” refer to CMI and its consolidated subsidiaries. CMI is a holding company with no significant operations other than those of its wholly-owned subsidiaries. The consolidated financial statements include the accounts of CMI and its wholly-owned domestic and foreign subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete consolidated financial statements. These unaudited consolidated financial statements should be read in conjunction with the consolidated financial statements of the Company for the annual period ended September 30, 2023, as filed with the Securities and Exchange Commission (the “SEC”) in its Annual Report on Form 10-K on November 29, 2023 (“2023 Form 10-K”). In the opinion of management, all adjustments, consisting of normal recurring adjustments considered necessary for a fair presentation, have been included. The Company experiences a substantial amount of seasonality in its sales, including its salt deicing product sales. Consequently, Salt segment sales and operating income are generally higher in the first and second fiscal quarters (ending December 31 and March 31) and lower during the third and fourth fiscal quarters (ending June 30 and September 30). In particular, sales of highway and consumer deicing salt and magnesium chloride products vary based on the severity of the winter conditions in areas where the products are used. Following industry practice in North America and the U.K., the Company seeks to stockpile sufficient quantities of deicing salt throughout the first, third and fourth fiscal quarters (ending December 31, June 30 and September 30) to meet the estimated requirements for the winter season. Production of deicing salt can also vary based on the severity or mildness of the preceding winter season. Due to the seasonal nature of the deicing product lines, operating results for the interim periods are not necessarily indicative of the results that may be expected for the full fiscal year. The Company’s plant nutrition business is also seasonal. As a result, the Company and its customers generally build inventories during the plant nutrition business’ low demand periods of the year (which are typically winter and summer, but can vary due to weather and other factors) to ensure timely product availability during the peak sales seasons (which are typically spring and autumn, but can also vary due to weather and other factors). Lastly, the results of the Company’s fire retardant business are also seasonal with peak demand for fire retardant products and services occurring from June through September. Significant Accounting Policies The Company’s significant accounting policies are detailed in “Note 2 – Summary of Significant Accounting Policies” within Part II, Item 8 of its 2023 Form 10-K. There were no material changes in our significant accounting policies from those described in our 2023 Form 10-K. Recent Accounting Pronouncements In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, “Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures”, which updates reportable segment disclosure requirements primarily to include enhanced disclosures about significant segment expenses. The amendments are effective for fiscal years beginning after December 15, 2023, and for interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The amendments should be applied retrospectively to all prior periods presented in the financial statements. Management is currently evaluating this ASU to determine its impact on the Company's disclosures. In December 2023, the FASB issued ASU 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures”, which updates income tax disclosures by requiring consistent categories and additional disaggregation of information in the rate reconciliation and income taxes paid by jurisdiction. The amendments are effective for fiscal years beginning after December 15, 2024. Early adoption is permitted. The amendments should be applied prospectively; however, retrospective application is permitted. Management is currently evaluating this ASU to determine its impact on the Company’s disclosures.

Business Acquisition

Business Acquisition	3 Months Ended
	Dec. 31, 2023
Business Combination and Asset Acquisition [Abstract]
Business Acquisition	Business Acquisition: Beginning in 2020, the Company began a series of equity investments in Fortress North America, LLC (“Fortress”), a next-generation fire retardant business dedicated to developing and producing a portfolio of magnesium chloride-based fire retardant products to help combat wildfires. On May 5, 2023, the Company acquired the remaining 55% interest in Fortress not previously owned in exchange for an initial cash payment of $18.9 million (net of cash held by Fortress of $6.5 million), and additional contingent consideration of up to $28 million to be paid in cash and/or Compass Minerals common stock upon the achievement of certain performance measures over the next five years, and a cash earn-out based on volumes of certain Fortress fire retardant products sold over a 10-year period. Building upon the previous 45% minority ownership stake in Fortress, the transaction provided the Company full ownership of all Fortress assets, contracts, and intellectual property. See Note 13 for fair value information related to the contingent consideration as of December 31, 2023.

Revenues

Revenues	3 Months Ended
	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Revenues	Revenues: Deferred Revenue Deferred revenue represents billings under non-cancellable contracts before the related product or service is transferred to the customer. The portion of deferred revenue that is anticipated to be recognized as revenue during the succeeding twelve-month period is recorded in accrued expenses and other current liabilities and the remaining portion is recorded in other non-current liabilities on the Consolidated Balance Sheets. Deferred revenue as of December 31, 2023 and September 30, 2023 was approximately $3.5 million and $8.5 million, respectively. See Note 10 for disaggregation of sales by segment, type and geographical region.

Inventories

Inventories	3 Months Ended
	Dec. 31, 2023
Inventory Disclosure [Abstract]
Inventories	Inventories: Inventories consist of the following (in millions): December 31, September 30, Finished goods $ 303.1 $ 319.3 Raw materials and supplies 89.4 72.9 Total inventories $ 392.5 $ 392.2

Property, Plant and Equipment,

Property, Plant and Equipment, Net	3 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, Net	Property, Plant and Equipment, Net: Property, plant and equipment, net, consists of the following (in millions): December 31, September 30, Land, buildings and structures, and leasehold improvements $ 555.4 $ 547.9 Machinery and equipment 1,132.1 1,102.0 Office furniture and equipment 22.3 21.6 Mineral interests 170.9 169.1 Construction in progress 58.6 113.0 1,939.3 1,953.6 Less: accumulated depreciation and depletion (1,136.3) (1,101.4) Property, plant and equipment, net $ 803.0 $ 852.2 The Company had been pursuing the development of a sustainable lithium salt resource to support the North American battery market. The passage of Utah House Bill 513 in March 2023 and the subsequent rulemaking process altered certain aspects of the regulatory landscape that will govern the development of lithium at the Great Salt Lake, introducing uncertainty into how development would proceed. As previously disclosed in the Company’s 2023 Form 10-K, the Company indefinitely paused new investment in its lithium development project pending greater clarity on the evolving regulatory environment in Utah. In December of 2023, a revised draft of the aforementioned rulemaking was published that continued to be, in the Company's assessment, adverse to its lithium development project. In addition, in December of 2023, the Company further refined its engineering estimates that, taken together with the proposed rules and decline in market price for lithium products, would result in inadequate risk-adjusted returns on capital. On January 23, 2024, the Company severed certain members of its lithium development team and terminated its pursuit of the lithium development. Consequently, the Company evaluated the capitalized assets, including site preparation, project engineering, equipment and materials and capitalized labor and interest. As a result, the Company recorded an impairment charge of $74.8 million, including $7.6 million associated with future commitments, as of December 31, 2023 to reflect the assets at their estimated fair value, considering equipment expected to be used by the on-going business and amounts estimated to be recoverable through returns or salvage value. Prior to recognizing an impairment, the Company had capitalized $72.7 million to its property, plant and equipment on its Consolidated Balance Sheet with approximately $5.5 million remaining as of December 31, 2023. The Company engaged a valuation specialist to assist in determining the appropriate fair value of the lithium assets and the resulting impairment charge. Given the assets are likely to either be used in other operations or liquidated at a later date, the Company utilized a market-based approach that relied on Level 3 inputs (see Note 13

Goodwill

Goodwill	3 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill: Changes in the carrying amount of goodwill are summarized as follows (in millions): Plant Nutrition Corporate & Other (a) Consolidated Balance as of September 30, 2023 $ 51.1 $ 45.7 $ 96.8 Foreign currency translation adjustment 0.2 0.2 0.4 Balance as of December 31, 2023 $ 51.3 $ 45.9 $ 97.2 (a) Includes approximately $40.0 million of goodwill related to the Company’s acquisition of Fortress, as discussed further in Note 2 .

Income Taxes

Income Taxes	3 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes: The Company’s effective income tax rate differs from the U.S. statutory federal income tax rate primarily due to U.S. statutory depletion, state income taxes (net of federal tax benefit), nondeductible executive compensation over $1 million, foreign income, mining and withholding taxes, base erosion and anti-abuse tax, and valuation allowances recorded on deferred tax assets. Management assesses the available positive and negative evidence to estimate whether sufficient future taxable income will be generated to permit use of the existing deferred tax assets. A significant piece of objective negative evidence evaluated was the cumulative loss incurred in the U.S. over the three-year period ended December 31, 2023. Such objective evidence limits the ability to consider other subjective evidence, such as the Company’s projections for future income. On the basis of this evaluation, during the three months ended December 31, 2023, an additional valuation allowance of $19.6 million has been recorded to recognize only the portion of the U.S. deferred tax assets that is more likely than not to be realized. The amount of the deferred tax assets considered realizable, however, could be adjusted if estimates of future taxable income during the carryforward period are increased or reduced or if objective negative evidence in the form of cumulative losses is no longer present and additional weight is given to subjective evidence such as the Company’s projections for income. As of December 31, 2023, and September 30, 2023, the Company had $63.1 million and $65.4 million, respectively of gross foreign federal NOL carryforwards that have no expiration date and $2.9 million at December 31, 2023 and September 30, 2023 of net operating tax-effected state NOL carryforwards which expire beginning in 2035. Canadian provincial tax authorities have challenged tax positions claimed by one of the Company’s Canadian subsidiaries and have issued tax reassessments for fiscal years 2002-2018. The reassessments are a result of ongoing audits and total $189.8 million, including interest, through December 31, 2023. The Company disputes these reassessments and will continue to work with the appropriate authorities in Canada to resolve the dispute. There is a reasonable possibility that the ultimate resolution of this dispute, and any related disputes for other open tax years, may be materially higher or lower than the amounts the Company has reserved for such disputes. In connection with this dispute, local regulations require the Company to post security with the tax authority until the dispute is resolved. The Company has posted collateral in the form of a $166.1 million performance bond and has paid $37.7 million to the Canadian tax authorities (most of which is recorded in other assets in the Consolidated Balance Sheets at December 31, 2023, and September 30, 2023), which is necessary to proceed with future appeals or litigation. The Company expects that it will be required by local regulations to provide security for additional interest on the above unresolved disputed amounts and for any future reassessments issued by these Canadian tax authorities in the form of cash, letters of credit, performance bonds, asset liens or other arrangements agreeable with the tax authorities until the disputes are resolved. The Company expects that the ultimate outcome of these matters will not have a material impact on its results of operations or financial condition. However, the Company can provide no assurance as to the ultimate outcome of these matters, and the impact could be material if they are not resolved in the Company’s favor. As of December 31, 2023, the Company believes it has adequately reserved for these reassessments. Additionally, the Company has other uncertain tax positions as well as assessments and disputed positions with taxing authorities in its various jurisdictions, which are consistent with those matters disclosed in the Company’s 2023 Form10-K.

Long-Term Debt

Long-Term Debt	3 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt: Long-term debt consists of the following (in millions): December 31, September 30, 6.75% Senior Notes due December 2027 $ 500.0 $ 500.0 Term Loan due May 2028 197.5 198.8 Revolving Credit Facility due May 2028 152.4 81.5 AR Securitization Facility expires June 2025 69.3 30.9 919.2 811.2 Less unamortized debt issuance costs (5.5) (5.9) Total debt 913.7 805.3 Less current portion (5.0) (5.0) Long-term debt $ 908.7 $ 800.3 As of December 31, 2023, the term loan and revolving credit facility under the 2023 Credit Agreement were secured by substantially all existing and future U.S. assets of the Company, the Goderich mine in Ontario, Canada and capital stock of certain subsidiaries. As of December 31, 2023 and September 30, 2023, the weighted average interest rate on all borrowings outstanding under the Credit Agreement was approximately 7.9% and 7.8%, respectively. Depending on the type, borrowings under the 2023 Credit Agreement accrue interest at a rate per annum equal to the Adjusted Term SOFR Rate, the Adjusted EURIBO Rate, Prime Rate or the CDO Rate (as defined in the credit agreement), as applicable, plus Applicable Margins (as defined in the credit agreement) which resulted in interest rates between 7.7% and 9.8% as of both December 31, 2023 and September 30, 2023. As of December 31, 2023 , the Company had $207.5 million of availability under its $375 million revolving credit facility. The term loan requires the Company to maintain certain financial ratios, including a minimum interest coverage ratio and a maximum total net leverage ratio. The Company is in compliance as of December 31, 2023 with its debt covenants under the 2023 Credit Agreement and its AR Securitization Facility. Pursuant to the terms of the 2023 Credit Agreement, the maximum allowed consolidated total net leverage ratio (as defined and calculated under the terms of the Credit Agreement and discussed further below) was 5.0x for the quarter ended December 31, 2023, which steps down to 4.75x in the quarter ending March 31, 2024, and to 4.5x for the fiscal quarter ended June 30, 2024 and thereafter. The consolidated total net leverage ratio represents the ratio of (a) consolidated total net debt to (b) consolidated adjusted earnings before interest, taxes, depreciation and amortization. Consolidated total net debt includes the aggregate principal amount of total debt, net of unrestricted cash not to exceed $75.0 million.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies: As previously disclosed, the Company was the subject of an investigation by the Division of Enforcement of the SEC regarding the Company’s disclosures primarily concerning the operation of the Goderich mine, the former South American businesses, and related accounting and internal control matters including Salt interim inventory valuation methodology issues that were disclosed in the Company’s Form 10-K/A for the year ended December 31, 2020, and Form 10-Q/A for the quarter ended March 31, 2021, each filed with the SEC on September 3, 2021. On September 23, 2022, the Company reached a settlement with the SEC, concluding and resolving the SEC investigation in its entirety. Under the terms of the settlement, the Company, without admitting or denying the findings in the administrative order issued by the SEC, agreed to pay a civil penalty of $12 million and to cease and desist from violations of specified provisions of the federal securities laws and rules promulgated thereunder, and to retain an independent compliance consultant for a period of approximately one year to review certain accounting practices and procedures. As set forth in the administrative order, the $12 million civil penalty was paid in installments with $10 million reflected in accrued expenses and other current liabilities on the Company’s Consolidated Balance Sheets as of September 30, 2023 and subsequently paid in during the first quarter of fiscal 2024. The Company is also involved in legal and administrative proceedings and claims of various types from the ordinary course of the Company’s business. Management cannot predict the outcome of legal claims and proceedings with certainty. Nevertheless, management believes that the outcome of legal proceedings and claims, which are pending or known to be threatened, even if determined adversely, will not, individually or in the aggregate, have a material adverse effect on the Company’s results of operations, cash flows or financial position, except as otherwise described in Note 7 and this Note 9.

Operating Segments

Operating Segments	3 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Operating Segments	Operating Segments: The Company’s reportable segments are strategic business units that offer different products and services, and each business requires different technology and marketing strategies. For the three months ended December 31, 2023 and 2022, the Company has presented two reportable segments in its Consolidated Financial Statements: Salt and Plant Nutrition. The Salt segment produces and markets salt, consisting of sodium chloride and magnesium chloride, for use in road deicing for winter roadway safety and for dust control, food processing, water softening and other consumer, agricultural and industrial applications. The Plant Nutrition segment produces and markets various grades of SOP. The results of operations for the Company’s fire retardant and records management businesses are included in Corporate and Other in the tables below. Refer to Note 2 for a discussion of the acquisition of the fire retardant business. Segment information is as follows (in millions): Three Months Ended December 31, 2023 Salt Plant Corporate & Other (a) Total Sales to external customers $ 274.3 $ 49.7 $ 17.7 $ 341.7 Intersegment sales — 3.1 (3.1) — Shipping and handling cost 83.7 7.0 0.6 91.3 Operating earnings (loss) (b) 50.5 (2.3) (103.5) (55.3) Depreciation, depletion and amortization 15.2 8.4 1.9 25.5 Total assets (as of end of period) 1,055.9 462.4 287.0 1,805.3 Three Months Ended December 31, 2022 Salt Plant Corporate & Other (a) Total Sales to external customers $ 308.1 $ 41.6 $ 2.7 $ 352.4 Intersegment sales — 2.9 (2.9) — Shipping and handling cost 102.7 4.7 — 107.4 Operating earnings (loss) (c) 47.1 11.0 (30.2) 27.9 Depreciation, depletion and amortization 13.9 8.3 1.7 23.9 Total assets (as of end of period) 985.2 456.5 323.0 1,764.7 Disaggregated revenue by product type is as follows (in millions): Three Months Ended December 31, 2023 Salt Plant Corporate & Other (a) Total Highway Deicing Salt $ 159.4 $ — $ — $ 159.4 Consumer & Industrial Salt 114.9 — — 114.9 SOP — 52.8 — 52.8 Fire Retardant — — 14.0 14.0 Revenue from Services — — 0.5 0.5 Eliminations & Other — (3.1) 3.2 0.1 Sales to external customers $ 274.3 $ 49.7 $ 17.7 $ 341.7 Three Months Ended December 31, 2022 Salt Plant Corporate & Other (a) Total Highway Deicing Salt $ 190.3 $ — $ — $ 190.3 Consumer & Industrial Salt 117.8 — — 117.8 SOP — 44.5 — 44.5 Eliminations & Other — (2.9) 2.7 (0.2) Sales to external customers $ 308.1 $ 41.6 $ 2.7 $ 352.4 (a) Corporate and Other includes corporate entities, records management operations, the Fortress fire retardant business, equity method investments, lithium development costs and other incidental operations and eliminations. Operating earnings (loss) for corporate and other includes indirect corporate overhead, including costs for general corporate governance and oversight, lithium-related expenses, as well as costs for the human resources, information technology, legal and finance functions. (b) As a result of the Company’s decision to cease the pursuit of the lithium development, the Company recognized an impairment of long-lived assets of $74.8 million and severance of $2.5 million, which impacted operating results for the three months ended December 31, 2023. Refer to Note 5 for additional information about the impairment of lithium development assets. (c) Corporate operating results include costs related to the settled SEC investigation of $0.3 million for the three months ended December 31, 2022. Refer to Note 9 for more information regarding the SEC investigation and settlement. The Company’s revenue by geographic area is as follows (in millions): Three Months Ended Revenue 2023 2022 United States (a) $ 250.9 $ 248.2 Canada 77.6 87.6 United Kingdom 13.0 14.1 Other 0.2 2.5 Total revenue $ 341.7 $ 352.4 (a) United States sales exclude product sold to foreign customers at U.S. ports.

Stockholders' Equity and Equity

Stockholders' Equity and Equity Instruments	3 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Stockholders' Equity and Equity Instruments	Stockholders’ Equity and Equity Instruments: Equity Compensation Awards In May 2020, the Company’s stockholders approved the 2020 Incentive Award Plan (as amended, the “2020 Plan”), which authorized the issuance of 2,977,933 shares of Company common stock. In February 2022, the Company’s stockholders approved an amendment to the 2020 Plan authorizing an additional 750,000 shares of Company stock. Since the date the 2020 Plan was approved, the Company ceased issuing equity awards under the 2015 Incentive Award Plan (as amended, the “2015 Plan”). Since the approval of the 2015 Plan in May 2015, the Company ceased issuing equity awards under the 2005 Incentive Award Plan (as amended, the “2005 Plan”). The 2005 Plan, the 2015 Plan and the 2020 Plan allow for grants of equity awards to executive officers, other employees and directors, including restricted stock units (“RSUs”), performance stock units (“PSUs”), stock options and deferred stock units. For additional information regarding equity awards issued under the Company’s incentive plans refer to “Note 16 – Stockholder’s Equity and Equity Instruments” within Part II, Item 8 of its 2023 Form 10-K. During the three months ended December 31, 2023, the Company reissued the following number of shares from treasury stock: 86,597 shares related to the release of RSUs which vested and 5,556 shares related to stock pay ments. In fiscal 2023, the Company issued 158,132 net shares from treasury stock. The Company withheld a total of 30,091 shares with a fair value of $0.8 million related to the vesting of RSUs during the three months ended December 31, 2023. The fair value of the shares was valued at the closing price at the vesting date and represent the employee tax withholding for the employee’s compensation. The Company recognized tax expense of $0.4 million from its equity compensation awards during the three months ended December 31, 2023. During the three months ended December 31, 2023 and 2022, the Company recorded $11.9 million and $10.6 million, respectively, of compensation expense pursuant to its stock-based compensation plans. No amounts have been capitalized. PSUs During the three months ended, December 31, 2023, the Company issued new PSUs based upon several operational performance measures (“Scorecard PSUs”). The actual number of shares of common stock that may be earned with respect to Scorecard PSUs is calculated based upon the attainment of free cash flow, cash unit costs, cash unit cost reduction, capital expenditures and safety measures during the performance period and may range from 0% to 300% for each measure. The following table summarizes stock-based compensation activity during the three months ended December 31, 2023: Stock Options RSUs PSUs (a) Number Weighted-average Number Weighted-average Number Weighted-average Outstanding at September 30, 2023 642,995 $ 59.46 393,240 $ 42.50 393,579 $ 71.37 Granted — — 404,852 27.22 171,669 27.24 Exercised (b) — — — — — — Released from restriction (b) — — (86,597) 46.53 — — Cancelled/expired (4,056) 63.11 (5,850) 34.39 (11,265) 63.83 Outstanding at December 31, 2023 638,939 $ 59.44 705,645 $ 33.31 553,983 $ 57.87 (a) Until the performance period is completed, PSUs are included in the table at the target level at their grant date and at that level represent one share of common stock per PSU. (b) Common stock issued for exercised options and for vested and earned RSUs and PSUs was issued from treasury stock. Accumulated Other Comprehensive Loss (“AOCL”) The Company’s comprehensive income (loss) is comprised of net earnings (loss), net amortization of the unrealized loss of the pension obligation, the change in the unrealized gain in other postretirement benefits, the change in the unrealized gain (loss) on natural gas and foreign currency cash flow hedges and CTA. The components of and changes in AOCL are as follows (in millions): Three Months Ended December 31, 2023 (a) Gains and (Losses) on Cash Flow Hedges Defined Benefit Pension Other Post-Employment Benefits Foreign Currency Total Beginning balance $ (1.4) $ (6.6) $ 1.7 $ (98.4) $ (104.7) Other comprehensive (loss) income before reclassifications (b) (2.6) — — 14.6 12.0 Amounts reclassified from AOCL 0.8 0.2 — — 1.0 Net current period other comprehensive (loss) income (1.8) 0.2 — 14.6 13.0 Ending balance $ (3.2) $ (6.4) $ 1.7 $ (83.8) $ (91.7) Three Months Ended December 31, 2022 (a) Losses on Cash Flow Hedges Defined Benefit Pension Other Post-Employment Benefits Foreign Currency Total Beginning balance $ (1.6) $ (2.7) $ 1.3 $ (112.3) $ (115.3) Other comprehensive (loss) income before reclassifications (b) (2.4) — — 11.7 9.3 Amounts reclassified from AOCL (0.4) 0.1 — — (0.3) Net current period other comprehensive (loss) income (2.8) 0.1 — 11.7 9.0 Ending balance $ (4.4) $ (2.6) $ 1.3 $ (100.6) $ (106.3) (a) With the exception of the CTA, for which no tax effect is recorded, the changes in the components of AOCL presented in the tables above are reflected net of applicable income taxes. (b) The Company recorded foreign exchange losses of $2.3 million and $1.3 million in the three months ended December 31, 2023 and 2022, respectively, in AOCL related to intercompany notes which were deemed to be of a long-term investment nature. The amounts reclassified from AOCL to expense (income) for the three months ended December 31, 2023 and 2022, are shown below (in millions): Amount Reclassified from AOCL Three Months Ended Line Item Impacted in the 2023 2022 Loss (gain) on cash flow hedges: Natural gas instruments $ 0.8 $ (0.5) Product cost Income tax expense — 0.1 Reclassifications, net of income taxes 0.8 (0.4) Amortization of defined benefit pension: Amortization of loss 0.3 0.1 Product cost Income tax benefit (0.1) — Reclassifications, net of income taxes 0.2 0.1 Amortization of other post-employment benefits: Amortization of loss — — Product cost Income tax benefit — — Reclassifications, net of income taxes — — Total reclassifications, net of income taxes $ 1.0 $ (0.3)

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments: The Company is subject to various types of market risks, including interest rate risk, foreign currency exchange rate transaction and translation risk and commodity pricing risk. Management may take actions to mitigate the exposure to these types of risks, including entering into forward purchase contracts and other financial instruments. The Company manages a portion of its commodity pricing risks and foreign currency exchange rate risks by using derivative instruments. From time to time, the Company may enter into foreign exchange contracts to mitigate foreign exchange risk. The Company does not seek to engage in trading activities or take speculative positions with any financial instrument arrangement. The Company enters into natural gas derivative instruments and foreign currency derivative instruments with counterparties it views as creditworthy. However, the Company does attempt to mitigate its counterparty credit risk exposures by, among other things, entering into master netting agreements with some of these counterparties. The Company records derivative financial instruments as either assets or liabilities at fair value in its Consolidated Balance Sheets. The assets and liabilities recorded as of December 31, 2023 and September 30, 2023 were not material. Derivatives qualify for treatment as hedges when there is a high correlation between the change in fair value of the derivative instrument and the related change in value of the underlying hedged item. Depending on the exposure being hedged, the Company must designate the hedging instrument as a fair value hedge, a cash flow hedge or a net investment in foreign operations hedge. For the qualifying derivative instruments that have been designated as cash flow hedges, the effective portion of the change in fair value is recognized through earnings when the underlying transaction being hedged affects earnings, allowing a derivative’s gains and losses to offset related results from the hedged item in the Consolidated Statements of Operations. Any ineffectiveness related to these instruments accounted for as hedges was not material for any of the periods presented. For derivative instruments that have not been designated as hedges, the entire change in fair value is recorded through earnings in the period of change. Natural Gas Derivative Instruments Natural gas is consumed at several of the Company’s production facilities, and changes in natural gas prices impact the Company’s operating margin. The Company seeks to reduce the earnings and cash flow impacts of changes in market prices of natural gas by fixing the purchase price of up to 90% of its forecasted natural gas usage. It is the Company’s policy to consider hedging portions of its natural gas usage up to 36 months in advance of the forecasted purchase. As of December 31, 2023, the Company had entered into natural gas derivative instruments to hedge a portion of its natural gas purchase requirements through September 2025. As of December 31, 2023 and September 30, 2023, the Company had agreements in place to hedge forecasted natural gas purchases of 3.2 million a nd 2.3 million MMBtus, respectively. On March 1, 2023, the Company de-designated its natural gas cash flow hedges related to its Ogden, Utah production facility as the Company did not believe these hedges were probable of being highly effective in the second fiscal quarter of 2023. Beginning March 1, 2023, the change in the derivative was and will be recorded in other expense, net in the Consolidated Statements of Operations. Since the transactions are still probable of occurring, previously recognized amounts in AOCL as of March 1, 2023, of $0.5 million will remain in AOCL until the underlying forecasted transaction occurs. The Company recognized $0.7 million of expense in other expense, net on the Consolidated Statements of Operations during the three months ended December 31, 2023. Following the de-designation, these natural gas economic hedging instruments will be recorded at fair value through earnings unless re-designated or until settlement. Substantially all other natural gas derivative instruments held by the Company as of December 31, 2023 and September 30, 2023 qualified and were designated as cash flow hedges. As of December 31, 2023, the Company expects to reclassify from AOCL to earnings during the next twelve months $3.2 million of net losses on derivative instruments related to its natural gas hedges. Refer to Note 13 for the estimated fair value of the Company’s natural gas derivative instruments as of December 31, 2023 and September 30, 2023. The following tables present the fair value of the Company’s derivatives (in millions): Asset Derivatives Liability Derivatives Consolidated Balance Sheet Location December 31, 2023 Consolidated Balance Sheet Location December 31, 2023 Derivatives designated as hedging instruments: Commodity contracts Other current assets $ 0.3 Accrued expenses and other current liabilities $ 3.5 Commodity contracts Other assets 0.3 Other noncurrent liabilities 0.4 Total derivatives designated as hedging instruments 0.6 3.9 Derivatives not designated as hedging instruments: Commodity contracts Other current assets — Accrued expenses and other current liabilities 0.4 Total derivatives not designated as hedging instruments — 0.4 Total derivatives (a) $ 0.6 $ 4.3 (a) The Company has master netting agreements with its commodity hedge counterparties and accordingly has netted in its Consolidated Balance Sheets $0.6 million of its commodity contracts that are in receivable positions against its contracts in payable positions. Asset Derivatives Liability Derivatives Consolidated Balance Sheet Location September 30, 2023 Consolidated Balance Sheet Location September 30, 2023 Derivatives designated as hedging instruments: Commodity contracts Other current assets $ 0.9 Accrued expenses and other current liabilities $ 2.3 Total derivatives designated as hedging instruments 0.9 2.3 Derivatives not designated as hedging instruments: Commodity contracts Other current assets 0.1 Accrued expenses and other current liabilities — Total derivatives not designated as hedging instruments 0.1 — Total derivatives (a) $ 1.0 $ 2.3 (a) The Company has master netting agreements with its commodity hedge counterparties and accordingly has netted in its Consolidated Balance Sheets $1.0 million of its commodity contracts that are in receivable positions against its contracts in payable positions.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements: The Company’s financial instruments are measured and reported at their estimated fair values. Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction. When available, the Company uses quoted prices in active markets to determine the fair values for its financial instruments (Level 1 inputs) or, absent quoted market prices, observable market-corroborated inputs over the term of the financial instruments (Level 2 inputs). The Company does not have any unobservable inputs that are not corroborated by market inputs (Level 3 inputs), except as stated below and in Note 2 . The Company holds marketable securities associated with its defined contribution and pre-tax savings plans, which are valued based on readily available quoted market prices. The Company utilizes derivative instruments to manage its risk of changes in natural gas prices and foreign exchange rates (see Note 12 ). The fair values of the natural gas and foreign currency derivative instruments are determined using market data of forward prices for all of the Company’s contracts. The estimated fair values for each type of instrument are presented below (in millions): December 31, Level One Level Two Level Three Asset Class: Mutual fund investments in a non-qualified savings plan (a) $ 3.0 $ 3.0 $ — $ — Total Assets $ 3.0 $ 3.0 $ — $ — Liability Class: Derivatives designated as hedging instruments - natural gas instruments, net $ (3.3) $ — $ (3.3) $ — Derivatives not designated as hedging instruments - natural gas instruments, net (0.4) — (0.4) — Liabilities related to non-qualified savings plan (3.0) (3.0) — — Total Liabilities $ (6.7) $ (3.0) $ (3.7) $ — (a) Includes mutual fund investments of approximately 25% in common stock of large-cap U.S. companies, 5% in common stock of small to mid-cap U.S. companies, 5% in international companies, 10% in bond funds, 5% in short-term investments and 50% in blended funds. September 30, Asset Class: Mutual fund investments in a non-qualified savings plan (a) $ 2.6 $ 2.6 $ — $ — Derivatives not designated as hedging instruments - natural gas instruments, net 0.1 — 0.1 — Total Assets $ 2.7 $ 2.6 $ 0.1 $ — Liability Class: Derivatives designated as hedging instruments - natural gas instruments, net $ (1.4) $ — $ (1.4) $ — Liabilities related to non-qualified savings plan (2.6) (2.6) — — Total Liabilities $ (4.0) $ (2.6) $ (1.4) $ — (a) Includes mutual fund investments of approximately 25% in the common stock of large-cap U.S. companies, 5% in the common stock of small to mid-cap U.S. companies, 10% in the common stock of international companies, 10% in bond funds, 5% in short-term investments and 45% in blended funds. Cash and cash equivalents, receivables (net of allowance for doubtful accounts) and accounts payable are carried at cost, which approximates fair value due to their liquid and short-term nature. The Company’s investments related to its non-qualified retirement plan of $3.0 million at December 31, 2023 and $2.6 million at September 30, 2023, are stated at fair value based on quoted market prices. As of December 31, 2023 and September 30, 2023, the estimated fair value of the Company’s fixed-rate 6.75% Senior Notes due December 2027, based on available trading information (Level 2), totaled $495.0 million and $472.5 million, respectively, compared with the aggregate principal amount at maturity of $500.0 million. The fair value at December 31, 2023 and September 30, 2023 of amounts outstanding under the Company’s term loans and revolving credit facility, based upon available bid information received from the Co mpany’s lender (Level 2), totaled approxima tely $345.6 million and $277.1 million, respectively, compared with the aggregate principal amount at maturity of $349.9 million and $280.3 million, respectively. In connection with the acquisition of Fortress, the Company entered into a contingent consideration arrangement (milestone and earnout payments). The fair value of the milestone contingent consideration is estimated using a probability-weighted discounted cash flow model with significant inputs not observable in the market and is therefore considered a Level 3 measurement while the earn-out is valued using a Monte Carlo simulation, also a Level 3 measurement. In the first quarter of fiscal 2024, the Company recorded $2.9 million of expense (substantially reflective of a change in discount rates and the passage of time) reflected in other operating expense in the Consolidated Statement of Operations to record the contingent consideration liability at its fair value as of December 31, 2023. The Company will continue to recognize remeasurement changes in the estimated fair value of contingent consideration in earnings at each reporting date until all contingencies are resolved. Refer to Note 2 for a discussion of the milestone and earnout payments. The following table presents the fair value of the Company’s total contingent consideration arrangement (in millions): Consolidated Balance Sheet Location December 31, 2023 September 30, 2023 Accrued expenses and other current liabilities $ 9.0 $ 8.4 Other noncurrent liabilities 37.6 35.3 Total contingent consideration $ 46.6 $ 43.7 The Company has certain assets, including goodwill and other intangible assets, which are measured at fair value on a non-recurring basis and are adjusted to fair value only if an impairment charge is recognized. The categorization of the framework used to measure fair value of the assets is considered to be within the Level 3 valuation hierarchy due to the subjective nature of the unobservable inputs used. Refer to Note 5

Earnings per Share

Earnings per Share	3 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share: The Company calculates earnings per share using the two-class method. The two-class method requires allocating the Company’s net earnings to both common shares and participating securities. The following table sets forth the computation of basic and diluted earnings per common share (in millions, except for share and per-share data): Three Months Ended 2023 2022 Numerator: Net loss from continuing operations $ (75.1) $ (0.3) Less: net earnings allocated to participating securities (a) (0.2) (0.1) Net loss available to common stockholders $ (75.3) $ (0.4) Denominator (in thousands): Weighted-average common shares outstanding, shares for basic earnings per share 41,205 39,751 Weighted-average awards outstanding (b) — — Shares for diluted earnings per share 41,205 39,751 Basic net loss per common share $ (1.83) $ (0.01) Diluted net loss per common share $ (1.83) $ (0.01) (a) Weighted participating securities include RSUs and PSUs that receive non-forfeitable dividends and consist of 777,000 weighted participating securities for the three months ended December 31, 2023 and 514,000 weighted participating securities for the three months ended December 31, 2022. (b)

Related Party Transactions

Related Party Transactions	3 Months Ended
	Dec. 31, 2023
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions: During the three months ended December 31, 2023, the Company recorded SOP sales of approximately $0.8 million to certain subsidiaries of Koch Industries, Inc., compared to $0.9 million during the three months ended December 31, 2022. As of December 31, 2023 and September 30, 2023, the Company had approximately $0.6 million and $0.4 million, respectively, of receivables from related parties on its Consolidated Balance Sheets. There were no amounts payable outstanding as of December 31, 2023.

Subsequent Events

Subsequent Events	3 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events: Departure of President, Chief Executive Officer and Board Member On January 15, 2024, the Compensation Committee of the Board of Directors of the Company approved, and the Company entered into, a separation and consulting agreement (the “Separation and Consulting Agreement”) with Kevin Crutchfield. Under the Separation and Consulting Agreement, Mr. Crutchfield ceased to serve as President, Chief Executive Officer and as a member of the Board, effective January 17, 2024. The Separation and Consulting Agreement provides that Mr. Crutchfield will serve as a consultant to the Company through September 30, 2024, at a rate of $22,500 per month (pro-rated for any partial months), and receive the severance payments and benefits that he is entitled to pursuant to his previously disclosed Amended and Restated Employment Agreement, dated August 5, 2022, subject to his execution of a release of claims. The Separation and Consulting Agreement also provides that Mr. Crutchfield will remain bound by certain restrictive covenants, including post-employment non-solicitation and confidentiality covenants. The Company expects to pay approximately $6.3 million of cash and to vest 104,597 RSUs (57,476 net RSUs after tax withholding), within 60 days following the effective date in the form of Severance Payments and Benefits, as defined in the Separation and Consulting Agreement. Appointment of New President, Chief Executive Officer On January 15, 2024, the Board appointed Edward C. Dowling, Jr. as the Company’s President and Chief Executive Officer, effective January 18, 2024. Mr. Dowling will continue to serve as a member of the Board of Directors, but will no longer serve as a member of the Compensation Committee of the Board of Directors. Departure of Chief Commercial Officer

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net earnings (loss)	$ (75.1)	$ (0.3)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Accounting Policies and Basis_2

Accounting Policies and Basis of Presentation (Policies)	3 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Consolidation	CMI is a holding company with no significant operations other than those of its wholly-owned subsidiaries. The consolidated financial statements include the accounts of CMI and its wholly-owned domestic and foreign subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation.
Basis of Presentation	The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete consolidated financial statements. These unaudited consolidated financial statements should be read in conjunction with the consolidated financial statements of the Company for the annual period ended September 30, 2023, as filed with the Securities and Exchange Commission (the “SEC”) in its Annual Report on Form 10-K on November 29, 2023 (“2023 Form 10-K”). In the opinion of management, all adjustments, consisting of normal recurring adjustments considered necessary for a fair presentation, have been included.
Significant and Recent Accounting Pronouncements	Significant Accounting Policies The Company’s significant accounting policies are detailed in “Note 2 – Summary of Significant Accounting Policies” within Part II, Item 8 of its 2023 Form 10-K. There were no material changes in our significant accounting policies from those described in our 2023 Form 10-K. Recent Accounting Pronouncements In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, “Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures”, which updates reportable segment disclosure requirements primarily to include enhanced disclosures about significant segment expenses. The amendments are effective for fiscal years beginning after December 15, 2023, and for interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The amendments should be applied retrospectively to all prior periods presented in the financial statements. Management is currently evaluating this ASU to determine its impact on the Company's disclosures. In December 2023, the FASB issued ASU 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures”, which updates income tax disclosures by requiring consistent categories and additional disaggregation of information in the rate reconciliation and income taxes paid by jurisdiction. The amendments are effective for fiscal years beginning after December 15, 2024. Early adoption is permitted. The amendments should be applied prospectively; however, retrospective application is permitted. Management is currently evaluating this ASU to determine its impact on the Company’s disclosures.
Revenues	Deferred Revenue
Derivative Financial Instruments	The Company is subject to various types of market risks, including interest rate risk, foreign currency exchange rate transaction and translation risk and commodity pricing risk. Management may take actions to mitigate the exposure to these types of risks, including entering into forward purchase contracts and other financial instruments. The Company manages a portion of its commodity pricing risks and foreign currency exchange rate risks by using derivative instruments. From time to time, the Company may enter into foreign exchange contracts to mitigate foreign exchange risk. The Company does not seek to engage in trading activities or take speculative positions with any financial instrument arrangement. The Company enters into natural gas derivative instruments and foreign currency derivative instruments with counterparties it views as creditworthy. However, the Company does attempt to mitigate its counterparty credit risk exposures by, among other things, entering into master netting agreements with some of these counterparties. The Company records derivative financial instruments as either assets or liabilities at fair value in its Consolidated Balance Sheets. The assets and liabilities recorded as of December 31, 2023 and September 30, 2023 were not material.
Earnings per Share	The Company calculates earnings per share using the two-class method. The two-class method requires allocating the Company’s net earnings to both common shares and participating securities.

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Dec. 31, 2023
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories consist of the following (in millions): December 31, September 30, Finished goods $ 303.1 $ 319.3 Raw materials and supplies 89.4 72.9 Total inventories $ 392.5 $ 392.2

Property, Plant and Equipment_2

Property, Plant and Equipment, Net (Tables)	3 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment, Net	Property, plant and equipment, net, consists of the following (in millions): December 31, September 30, Land, buildings and structures, and leasehold improvements $ 555.4 $ 547.9 Machinery and equipment 1,132.1 1,102.0 Office furniture and equipment 22.3 21.6 Mineral interests 170.9 169.1 Construction in progress 58.6 113.0 1,939.3 1,953.6 Less: accumulated depreciation and depletion (1,136.3) (1,101.4) Property, plant and equipment, net $ 803.0 $ 852.2

Goodwill (Tables)

Goodwill (Tables)	3 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	Changes in the carrying amount of goodwill are summarized as follows (in millions): Plant Nutrition Corporate & Other (a) Consolidated Balance as of September 30, 2023 $ 51.1 $ 45.7 $ 96.8 Foreign currency translation adjustment 0.2 0.2 0.4 Balance as of December 31, 2023 $ 51.3 $ 45.9 $ 97.2 (a) Includes approximately $40.0 million of goodwill related to the Company’s acquisition of Fortress, as discussed further in Note 2 .

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Schedule of Long-Term Debt	Long-term debt consists of the following (in millions): December 31, September 30, 6.75% Senior Notes due December 2027 $ 500.0 $ 500.0 Term Loan due May 2028 197.5 198.8 Revolving Credit Facility due May 2028 152.4 81.5 AR Securitization Facility expires June 2025 69.3 30.9 919.2 811.2 Less unamortized debt issuance costs (5.5) (5.9) Total debt 913.7 805.3 Less current portion (5.0) (5.0) Long-term debt $ 908.7 $ 800.3

Operating Segments (Tables)

Operating Segments (Tables)	3 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Schedule of Segment Information	Segment information is as follows (in millions): Three Months Ended December 31, 2023 Salt Plant Corporate & Other (a) Total Sales to external customers $ 274.3 $ 49.7 $ 17.7 $ 341.7 Intersegment sales — 3.1 (3.1) — Shipping and handling cost 83.7 7.0 0.6 91.3 Operating earnings (loss) (b) 50.5 (2.3) (103.5) (55.3) Depreciation, depletion and amortization 15.2 8.4 1.9 25.5 Total assets (as of end of period) 1,055.9 462.4 287.0 1,805.3 Three Months Ended December 31, 2022 Salt Plant Corporate & Other (a) Total Sales to external customers $ 308.1 $ 41.6 $ 2.7 $ 352.4 Intersegment sales — 2.9 (2.9) — Shipping and handling cost 102.7 4.7 — 107.4 Operating earnings (loss) (c) 47.1 11.0 (30.2) 27.9 Depreciation, depletion and amortization 13.9 8.3 1.7 23.9 Total assets (as of end of period) 985.2 456.5 323.0 1,764.7
Schedule of Disaggregated Revenue by Product Type	Disaggregated revenue by product type is as follows (in millions): Three Months Ended December 31, 2023 Salt Plant Corporate & Other (a) Total Highway Deicing Salt $ 159.4 $ — $ — $ 159.4 Consumer & Industrial Salt 114.9 — — 114.9 SOP — 52.8 — 52.8 Fire Retardant — — 14.0 14.0 Revenue from Services — — 0.5 0.5 Eliminations & Other — (3.1) 3.2 0.1 Sales to external customers $ 274.3 $ 49.7 $ 17.7 $ 341.7 Three Months Ended December 31, 2022 Salt Plant Corporate & Other (a) Total Highway Deicing Salt $ 190.3 $ — $ — $ 190.3 Consumer & Industrial Salt 117.8 — — 117.8 SOP — 44.5 — 44.5 Eliminations & Other — (2.9) 2.7 (0.2) Sales to external customers $ 308.1 $ 41.6 $ 2.7 $ 352.4 (a) Corporate and Other includes corporate entities, records management operations, the Fortress fire retardant business, equity method investments, lithium development costs and other incidental operations and eliminations. Operating earnings (loss) for corporate and other includes indirect corporate overhead, including costs for general corporate governance and oversight, lithium-related expenses, as well as costs for the human resources, information technology, legal and finance functions. (b) As a result of the Company’s decision to cease the pursuit of the lithium development, the Company recognized an impairment of long-lived assets of $74.8 million and severance of $2.5 million, which impacted operating results for the three months ended December 31, 2023. Refer to Note 5 for additional information about the impairment of lithium development assets. (c) Corporate operating results include costs related to the settled SEC investigation of $0.3 million for the three months ended December 31, 2022. Refer to Note 9
Schedule of Revenue by Geographic Area	The Company’s revenue by geographic area is as follows (in millions): Three Months Ended Revenue 2023 2022 United States (a) $ 250.9 $ 248.2 Canada 77.6 87.6 United Kingdom 13.0 14.1 Other 0.2 2.5 Total revenue $ 341.7 $ 352.4 (a) United States sales exclude product sold to foreign customers at U.S. ports.

Stockholders' Equity and Equi_2

Stockholders' Equity and Equity Instruments (Tables)	3 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Schedule of Stock-Based Compensation Activity	The following table summarizes stock-based compensation activity during the three months ended December 31, 2023: Stock Options RSUs PSUs (a) Number Weighted-average Number Weighted-average Number Weighted-average Outstanding at September 30, 2023 642,995 $ 59.46 393,240 $ 42.50 393,579 $ 71.37 Granted — — 404,852 27.22 171,669 27.24 Exercised (b) — — — — — — Released from restriction (b) — — (86,597) 46.53 — — Cancelled/expired (4,056) 63.11 (5,850) 34.39 (11,265) 63.83 Outstanding at December 31, 2023 638,939 $ 59.44 705,645 $ 33.31 553,983 $ 57.87 (a) Until the performance period is completed, PSUs are included in the table at the target level at their grant date and at that level represent one share of common stock per PSU. (b) Common stock issued for exercised options and for vested and earned RSUs and PSUs was issued from treasury stock.
Schedule of Components and Changes in Accumulated Other Comprehensive Income (Loss)	The components of and changes in AOCL are as follows (in millions): Three Months Ended December 31, 2023 (a) Gains and (Losses) on Cash Flow Hedges Defined Benefit Pension Other Post-Employment Benefits Foreign Currency Total Beginning balance $ (1.4) $ (6.6) $ 1.7 $ (98.4) $ (104.7) Other comprehensive (loss) income before reclassifications (b) (2.6) — — 14.6 12.0 Amounts reclassified from AOCL 0.8 0.2 — — 1.0 Net current period other comprehensive (loss) income (1.8) 0.2 — 14.6 13.0 Ending balance $ (3.2) $ (6.4) $ 1.7 $ (83.8) $ (91.7) Three Months Ended December 31, 2022 (a) Losses on Cash Flow Hedges Defined Benefit Pension Other Post-Employment Benefits Foreign Currency Total Beginning balance $ (1.6) $ (2.7) $ 1.3 $ (112.3) $ (115.3) Other comprehensive (loss) income before reclassifications (b) (2.4) — — 11.7 9.3 Amounts reclassified from AOCL (0.4) 0.1 — — (0.3) Net current period other comprehensive (loss) income (2.8) 0.1 — 11.7 9.0 Ending balance $ (4.4) $ (2.6) $ 1.3 $ (100.6) $ (106.3) (a) With the exception of the CTA, for which no tax effect is recorded, the changes in the components of AOCL presented in the tables above are reflected net of applicable income taxes. (b) The Company recorded foreign exchange losses of $2.3 million and $1.3 million in the three months ended December 31, 2023 and 2022, respectively, in AOCL related to intercompany notes which were deemed to be of a long-term investment nature.
Schedule of Reclassifications out of Accumulated Other Comprehensive Income	The amounts reclassified from AOCL to expense (income) for the three months ended December 31, 2023 and 2022, are shown below (in millions): Amount Reclassified from AOCL Three Months Ended Line Item Impacted in the 2023 2022 Loss (gain) on cash flow hedges: Natural gas instruments $ 0.8 $ (0.5) Product cost Income tax expense — 0.1 Reclassifications, net of income taxes 0.8 (0.4) Amortization of defined benefit pension: Amortization of loss 0.3 0.1 Product cost Income tax benefit (0.1) — Reclassifications, net of income taxes 0.2 0.1 Amortization of other post-employment benefits: Amortization of loss — — Product cost Income tax benefit — — Reclassifications, net of income taxes — — Total reclassifications, net of income taxes $ 1.0 $ (0.3)

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	3 Months Ended
	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Fair Value of Hedges	The following tables present the fair value of the Company’s derivatives (in millions): Asset Derivatives Liability Derivatives Consolidated Balance Sheet Location December 31, 2023 Consolidated Balance Sheet Location December 31, 2023 Derivatives designated as hedging instruments: Commodity contracts Other current assets $ 0.3 Accrued expenses and other current liabilities $ 3.5 Commodity contracts Other assets 0.3 Other noncurrent liabilities 0.4 Total derivatives designated as hedging instruments 0.6 3.9 Derivatives not designated as hedging instruments: Commodity contracts Other current assets — Accrued expenses and other current liabilities 0.4 Total derivatives not designated as hedging instruments — 0.4 Total derivatives (a) $ 0.6 $ 4.3 (a) The Company has master netting agreements with its commodity hedge counterparties and accordingly has netted in its Consolidated Balance Sheets $0.6 million of its commodity contracts that are in receivable positions against its contracts in payable positions. Asset Derivatives Liability Derivatives Consolidated Balance Sheet Location September 30, 2023 Consolidated Balance Sheet Location September 30, 2023 Derivatives designated as hedging instruments: Commodity contracts Other current assets $ 0.9 Accrued expenses and other current liabilities $ 2.3 Total derivatives designated as hedging instruments 0.9 2.3 Derivatives not designated as hedging instruments: Commodity contracts Other current assets 0.1 Accrued expenses and other current liabilities — Total derivatives not designated as hedging instruments 0.1 — Total derivatives (a) $ 1.0 $ 2.3 (a) The Company has master netting agreements with its commodity hedge counterparties and accordingly has netted in its Consolidated Balance Sheets $1.0 million of its commodity contracts that are in receivable positions against its contracts in payable positions.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The estimated fair values for each type of instrument are presented below (in millions): December 31, Level One Level Two Level Three Asset Class: Mutual fund investments in a non-qualified savings plan (a) $ 3.0 $ 3.0 $ — $ — Total Assets $ 3.0 $ 3.0 $ — $ — Liability Class: Derivatives designated as hedging instruments - natural gas instruments, net $ (3.3) $ — $ (3.3) $ — Derivatives not designated as hedging instruments - natural gas instruments, net (0.4) — (0.4) — Liabilities related to non-qualified savings plan (3.0) (3.0) — — Total Liabilities $ (6.7) $ (3.0) $ (3.7) $ — (a) Includes mutual fund investments of approximately 25% in common stock of large-cap U.S. companies, 5% in common stock of small to mid-cap U.S. companies, 5% in international companies, 10% in bond funds, 5% in short-term investments and 50% in blended funds. September 30, Asset Class: Mutual fund investments in a non-qualified savings plan (a) $ 2.6 $ 2.6 $ — $ — Derivatives not designated as hedging instruments - natural gas instruments, net 0.1 — 0.1 — Total Assets $ 2.7 $ 2.6 $ 0.1 $ — Liability Class: Derivatives designated as hedging instruments - natural gas instruments, net $ (1.4) $ — $ (1.4) $ — Liabilities related to non-qualified savings plan (2.6) (2.6) — — Total Liabilities $ (4.0) $ (2.6) $ (1.4) $ — (a) Includes mutual fund investments of approximately 25% in the common stock of large-cap U.S. companies, 5% in the common stock of small to mid-cap U.S. companies, 10% in the common stock of international companies, 10% in bond funds, 5% in short-term investments and 45% in blended funds.
Schedule of Business Acquisitions by Acquisition, Contingent Consideration	The following table presents the fair value of the Company’s total contingent consideration arrangement (in millions): Consolidated Balance Sheet Location December 31, 2023 September 30, 2023 Accrued expenses and other current liabilities $ 9.0 $ 8.4 Other noncurrent liabilities 37.6 35.3 Total contingent consideration $ 46.6 $ 43.7

Earnings per Share (Tables)

Earnings per Share (Tables)	3 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Earnings Per Common Share	The following table sets forth the computation of basic and diluted earnings per common share (in millions, except for share and per-share data): Three Months Ended 2023 2022 Numerator: Net loss from continuing operations $ (75.1) $ (0.3) Less: net earnings allocated to participating securities (a) (0.2) (0.1) Net loss available to common stockholders $ (75.3) $ (0.4) Denominator (in thousands): Weighted-average common shares outstanding, shares for basic earnings per share 41,205 39,751 Weighted-average awards outstanding (b) — — Shares for diluted earnings per share 41,205 39,751 Basic net loss per common share $ (1.83) $ (0.01) Diluted net loss per common share $ (1.83) $ (0.01) (a) Weighted participating securities include RSUs and PSUs that receive non-forfeitable dividends and consist of 777,000 weighted participating securities for the three months ended December 31, 2023 and 514,000 weighted participating securities for the three months ended December 31, 2022. (b)

Business Acquisition - Narrativ

Business Acquisition - Narrative (Details) - USD ($) $ in Millions	May 05, 2023	Dec. 31, 2023	Sep. 30, 2023
Business Acquisition [Line Items]
Contingent consideration, liability		$ 46.6	$ 43.7
Fortress
Business Acquisition [Line Items]
Ownership interest in investment	45%
Fortress
Business Acquisition [Line Items]
Remaining interest acquired (as a percent)	55%
Acquisition of business, net of cash acquired	$ 18.9
Cash held by acquiree	6.5
Contingent consideration, liability	$ 28
Performance period	5 years
Contingent consideration period	10 years

Revenues (Details)

Revenues (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Deferred revenue	$ 3.5	$ 8.5

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Inventory Disclosure [Abstract]
Finished goods	$ 303.1	$ 319.3
Raw materials and supplies	89.4	72.9
Total inventories	$ 392.5	$ 392.2

Property, Plant and Equipment_3

Property, Plant and Equipment, Net (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023
Property, Plant and Equipment [Line Items]
Total property plant and equipment	$ 1,939.3		$ 1,953.6
Less: accumulated depreciation and depletion	(1,136.3)		(1,101.4)
Property, plant and equipment, net	803		852.2
Loss on impairment of long-lived assets, net	74.8	$ 0
Loss on impairment of long-lived assets, future commitments	7.6
Land, buildings and structures, and leasehold improvements
Property, Plant and Equipment [Line Items]
Total property plant and equipment	555.4		547.9
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property plant and equipment	1,132.1		1,102
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Total property plant and equipment	22.3		21.6
Mineral interests
Property, Plant and Equipment [Line Items]
Total property plant and equipment	170.9		169.1
Construction in progress
Property, Plant and Equipment [Line Items]
Total property plant and equipment	58.6		$ 113
Lithium Salt Resource
Property, Plant and Equipment [Line Items]
Property, plant and equipment	72.7
Property, plant and equipment remaining	$ 5.5

Goodwill (Details)

Goodwill (Details) $ in Millions	3 Months Ended
	Dec. 31, 2023 USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 96.8
Foreign currency translation adjustment	0.4
Goodwill, ending balance	97.2
Plant Nutrition
Goodwill [Roll Forward]
Goodwill, beginning balance	51.1
Foreign currency translation adjustment	0.2
Goodwill, ending balance	51.3
Corporate & Other
Goodwill [Roll Forward]
Goodwill, beginning balance	45.7
Foreign currency translation adjustment	0.2
Goodwill, ending balance	45.9
Corporate & Other | Fortress
Goodwill [Roll Forward]
Acquisition of business	$ 40

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Sep. 30, 2023
Income Tax Disclosure [Line Items]
Nondeductible executive compensation	$ 1
U.S. Federal
Income Tax Disclosure [Line Items]
Deferred tax asset valuation allowance recorded	19.6
Foreign Tax Authority
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	63.1	$ 65.4
Foreign Tax Authority | Canadian Tax Authority
Income Tax Disclosure [Line Items]
Total reassessments including interest	189.8
Amount of security posted in the form of a performance bond	166.1
Amount of security posted in the form of cash	37.7	37.7
State and Local | NOL carryforwards expire beginning in 2035
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 2.9	$ 2.9

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Debt Instrument [Line Items]
Long-term debt, gross	$ 919.2	$ 811.2
Less unamortized debt issuance costs	(5.5)	(5.9)
Total debt	913.7	805.3
Less current portion	(5)	(5)
Long-term debt	$ 908.7	$ 800.3
Senior Notes | 6.75% Senior Notes due December 2027
Debt Instrument [Line Items]
Stated interest rate (as a percent)	6.75%	6.75%
Long-term debt, gross	$ 500	$ 500
Line of Credit | Term Loan due May 2028
Debt Instrument [Line Items]
Long-term debt, gross	197.5	198.8
Line of Credit | Revolving Credit Facility due May 2028
Debt Instrument [Line Items]
Long-term debt, gross	152.4	81.5
Line of Credit | AR Securitization Facility expires June 2025
Debt Instrument [Line Items]
Long-term debt, gross	$ 69.3	$ 30.9

Long-Term Debt - Narrative (Det

Long-Term Debt - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023
Quarter ending June 30, 2023
Debt Instrument [Line Items]
Consolidated total net leverage ratio		500%
Quarter ending June 30, 2023 | Scenario, Forecast
Debt Instrument [Line Items]
Consolidated total net leverage ratio	475%
Fiscal quarter ended June 30, 2024
Debt Instrument [Line Items]
Consolidated total net leverage ratio		450%
Line of Credit | Revolving Credit Facility Due January 2025
Debt Instrument [Line Items]
Weighted average interest rate of debt (as a percent)		7.90%	7.80%
Line of Credit | Revolving Credit Facility Due January 2025 | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Weighted average interest rate of debt (as a percent)		7.70%	9.80%
Line of Credit | Revolving Credit Facility | Revolving Credit Facility Due January 2025
Debt Instrument [Line Items]
Maximum unrestricted cash		$ 75
Line of Credit | Revolving Credit Facility | 2023 Credit Agreement
Debt Instrument [Line Items]
Availability under revolving credit facility		207.5
Aggregate principal amount of credit facility		$ 375

Commitments and Contingencies (

Commitments and Contingencies (Details) - SEC Investigation $ in Millions	Sep. 23, 2022 USD ($)
Loss Contingencies [Line Items]
Loss contingency, damages sought, value	$ 12
Contingent loss accrual	$ 10

Operating Segments (Details)

Operating Segments (Details) $ in Millions	3 Months Ended
	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($) segment
Segment Reporting [Abstract]
Number of reportable segments | segment	2	2
Segment Reporting Information [Abstract]
Sales	$ 341.7	$ 352.4
Operating earnings (loss)	(55.3)	27.9
Depreciation, depletion and amortization	25.5	23.9
Total assets (as of end of period)	1,805.3	1,764.7
Loss on impairment of long-lived assets, net	74.8	0
Severance costs	2.5
Accrued loss reserve		0.3
United States
Segment Reporting Information [Abstract]
Sales	250.9	248.2
Canada
Segment Reporting Information [Abstract]
Sales	77.6	87.6
United Kingdom
Segment Reporting Information [Abstract]
Sales	13	14.1
Other
Segment Reporting Information [Abstract]
Sales	0.2	2.5
Shipping and handling cost
Segment Reporting Information [Abstract]
Shipping and handling cost	91.3	107.4
Highway Deicing Salt
Segment Reporting Information [Abstract]
Sales	159.4	190.3
Consumer & Industrial Salt
Segment Reporting Information [Abstract]
Sales	114.9	117.8
SOP
Segment Reporting Information [Abstract]
Sales	52.8	44.5
Fire Retardant
Segment Reporting Information [Abstract]
Sales	14
Revenue from Services
Segment Reporting Information [Abstract]
Sales	0.5
Eliminations & Other
Segment Reporting Information [Abstract]
Sales	0.1	(0.2)
Operating Segments | Salt
Segment Reporting Information [Abstract]
Sales	274.3	308.1
Operating earnings (loss)	50.5	47.1
Depreciation, depletion and amortization	15.2	13.9
Total assets (as of end of period)	1,055.9	985.2
Operating Segments | Salt | Shipping and handling cost
Segment Reporting Information [Abstract]
Shipping and handling cost	83.7	102.7
Operating Segments | Salt | Highway Deicing Salt
Segment Reporting Information [Abstract]
Sales	159.4	190.3
Operating Segments | Salt | Consumer & Industrial Salt
Segment Reporting Information [Abstract]
Sales	114.9	117.8
Operating Segments | Salt | SOP
Segment Reporting Information [Abstract]
Sales	0	0
Operating Segments | Salt | Fire Retardant
Segment Reporting Information [Abstract]
Sales	0
Operating Segments | Salt | Revenue from Services
Segment Reporting Information [Abstract]
Sales	0
Operating Segments | Salt | Eliminations & Other
Segment Reporting Information [Abstract]
Sales	0	0
Operating Segments | Plant Nutrition
Segment Reporting Information [Abstract]
Sales	49.7	41.6
Operating earnings (loss)	(2.3)	11
Depreciation, depletion and amortization	8.4	8.3
Total assets (as of end of period)	462.4	456.5
Operating Segments | Plant Nutrition | Shipping and handling cost
Segment Reporting Information [Abstract]
Shipping and handling cost	7	4.7
Operating Segments | Plant Nutrition | Highway Deicing Salt
Segment Reporting Information [Abstract]
Sales	0	0
Operating Segments | Plant Nutrition | Consumer & Industrial Salt
Segment Reporting Information [Abstract]
Sales	0	0
Operating Segments | Plant Nutrition | SOP
Segment Reporting Information [Abstract]
Sales	52.8	44.5
Operating Segments | Plant Nutrition | Fire Retardant
Segment Reporting Information [Abstract]
Sales	0
Operating Segments | Plant Nutrition | Revenue from Services
Segment Reporting Information [Abstract]
Sales	0
Operating Segments | Plant Nutrition | Eliminations & Other
Segment Reporting Information [Abstract]
Sales	(3.1)	(2.9)
Corporate & Other
Segment Reporting Information [Abstract]
Sales	17.7	2.7
Operating earnings (loss)	(103.5)	(30.2)
Depreciation, depletion and amortization	1.9	1.7
Total assets (as of end of period)	287	323
Corporate & Other | Shipping and handling cost
Segment Reporting Information [Abstract]
Shipping and handling cost	0.6	0
Corporate & Other | Highway Deicing Salt
Segment Reporting Information [Abstract]
Sales	0	0
Corporate & Other | Consumer & Industrial Salt
Segment Reporting Information [Abstract]
Sales	0	0
Corporate & Other | SOP
Segment Reporting Information [Abstract]
Sales	0	0
Corporate & Other | Fire Retardant
Segment Reporting Information [Abstract]
Sales	14
Corporate & Other | Revenue from Services
Segment Reporting Information [Abstract]
Sales	0.5
Corporate & Other | Eliminations & Other
Segment Reporting Information [Abstract]
Sales	3.2	2.7
Intersegment Eliminations
Segment Reporting Information [Abstract]
Sales	(3.1)	(2.9)
Intersegment Eliminations | Salt
Segment Reporting Information [Abstract]
Sales	0	0
Intersegment Eliminations | Plant Nutrition
Segment Reporting Information [Abstract]
Sales	$ 3.1	$ 2.9

Stockholders' Equity and Equi_3

Stockholders' Equity and Equity Instruments - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Feb. 28, 2022	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023	May 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Treasury stock reissued (in shares)				158,132
Tax deficiency from equity compensation awards recorded as an increase to income tax expense		$ 0.4
Share-based payment arrangement, expense		$ 11.9	$ 10.6
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reissued share of treasury stock		86,597
Stock Payments
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reissued share of treasury stock		5,556
Equity Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares withheld related to vesting of RSUs and PSUs (in shares)		30,091
Fair value of stock withheld related to vesting of RSUs and PSUs		$ 0.8
Minimum | Scorecard PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation payment award performance percentage		0%
Maximum | Scorecard PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation payment award performance percentage		300%
2020 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance (in shares)					2,977,933
Shares authorized for issuance (in shares)	750,000

Stockholders' Equity and Equi_4

Stockholders' Equity and Equity Instruments - Schedule of Stock-Based Compensation Activity (Details)	3 Months Ended
	Dec. 31, 2023 $ / shares shares
Stock Options
Number
Outstanding at beginning of period (in shares)	642,995
Granted (in shares)	0
Exercised (in shares)	0
Released from restriction (in shares)	0
Cancelled/expired (in shares)	(4,056)
Outstanding at end of period (in shares)	638,939
Weighted-average exercise price
Weighted-average exercise price at beginning of period (in dollars per share) | $ / shares	$ 59.46
Weighted-average exercise price, granted (in dollars per share) | $ / shares	0
Weighted-average exercise price, exercised (in dollars per share) | $ / shares	0
Weighted-average exercise price, released from restriction (in dollars per share) | $ / shares	0
Weighted-average exercise price, cancelled/expired (in dollars per share) | $ / shares	63.11
Weighted-average exercise price at end of period (in dollars per share) | $ / shares	$ 59.44
RSUs
Number
Outstanding at beginning of period (in shares)	393,240
Granted (in shares)	404,852
Exercised (in shares)	0
Released from restriction (in shares)	(86,597)
Cancelled/expired (in shares)	(5,850)
Outstanding at end of period (in shares)	705,645
Weighted-average fair value
Weighted-average fair value at beginning of period (in dollars per share) | $ / shares	$ 42.50
Weighted-average fair value, granted (in dollars per share) | $ / shares	27.22
Weighted-average fair value, exercised (in dollars per share) | $ / shares	0
Weighted-average fair value, released from restriction (in dollars per share) | $ / shares	46.53
Weighted-average fair value, cancelled/expired (in dollars per share) | $ / shares	34.39
Weighted-average fair value at end of period (in dollars per share) | $ / shares	$ 33.31
PSUs
Number
Outstanding at beginning of period (in shares)	393,579
Granted (in shares)	171,669
Exercised (in shares)	0
Released from restriction (in shares)	0
Cancelled/expired (in shares)	(11,265)
Outstanding at end of period (in shares)	553,983
Weighted-average fair value
Weighted-average fair value at beginning of period (in dollars per share) | $ / shares	$ 71.37
Weighted-average fair value, granted (in dollars per share) | $ / shares	27.24
Weighted-average fair value, exercised (in dollars per share) | $ / shares	0
Weighted-average fair value, released from restriction (in dollars per share) | $ / shares	0
Weighted-average fair value, cancelled/expired (in dollars per share) | $ / shares	63.83
Weighted-average fair value at end of period (in dollars per share) | $ / shares	$ 57.87
PSU at grant date (in shares per unit)	1

Stockholders' Equity and Equi_5

Stockholders' Equity and Equity Instruments - Schedule of Components and Changes In AOCL (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 517.2	$ 256.4
Other comprehensive (loss) income before reclassifications	12	9.3
Amounts reclassified from AOCL	1	(0.3)
Net current period other comprehensive (loss) income	13	9
Ending balance	459.8	509.8
Loss on foreign exchange of intercompany notes of long-term nature	2.3	1.3
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(104.7)	(115.3)
Ending balance	(91.7)	(106.3)
Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(1.4)	(1.6)
Other comprehensive (loss) income before reclassifications	(2.6)	(2.4)
Amounts reclassified from AOCL	0.8	(0.4)
Net current period other comprehensive (loss) income	(1.8)	(2.8)
Ending balance	(3.2)	(4.4)
Benefit Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance		(2.7)
Other comprehensive (loss) income before reclassifications		0
Amounts reclassified from AOCL		0.1
Net current period other comprehensive (loss) income		0.1
Ending balance		(2.6)
Benefit Plans | Defined Benefit Pension
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(6.6)
Other comprehensive (loss) income before reclassifications	0
Amounts reclassified from AOCL	0.2
Net current period other comprehensive (loss) income	0.2
Ending balance	(6.4)
Benefit Plans | Other Post-Employment Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	1.7	1.3
Other comprehensive (loss) income before reclassifications	0	0
Amounts reclassified from AOCL	0	0
Net current period other comprehensive (loss) income	0	0
Ending balance	1.7	1.3
Foreign Currency
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(98.4)	(112.3)
Other comprehensive (loss) income before reclassifications	14.6	11.7
Amounts reclassified from AOCL	0	0
Net current period other comprehensive (loss) income	14.6	11.7
Ending balance	$ (83.8)	$ (100.6)

Stockholders' Equity and Equi_6

Stockholders' Equity and Equity Instruments - Schedule of Reclassifications From AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax benefit (expense)	$ 1.8	$ 11.9
Net earnings (loss)	(75.1)	(0.3)
Product cost
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Product cost	(179.8)	(175)
Amount Reclassified from AOCL
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net earnings (loss)	1	(0.3)
Amount Reclassified from AOCL | Loss (gain) on cash flow hedges:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax benefit (expense)	0	0.1
Net earnings (loss)	0.8	(0.4)
Amount Reclassified from AOCL | Loss (gain) on cash flow hedges: | Natural gas instruments | Product cost
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Product cost	0.8	(0.5)
Amount Reclassified from AOCL | Amortization of defined benefit pension:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax benefit (expense)	(0.1)	0
Net earnings (loss)	0.2	0.1
Amount Reclassified from AOCL | Amortization of defined benefit pension: | Product cost
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Product cost	0.3	0.1
Amount Reclassified from AOCL | Amortization of other post-employment benefits:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax benefit (expense)	0	0
Net earnings (loss)	0	0
Amount Reclassified from AOCL | Amortization of other post-employment benefits: | Product cost
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Product cost	$ 0	$ 0

Derivative Financial Instrume_3

Derivative Financial Instruments - Narrative (Details) MMBTU in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2023 USD ($) MMBTU	Dec. 31, 2022 USD ($)	Mar. 31, 2023 MMBTU	Sep. 30, 2023 USD ($)	Mar. 01, 2023 USD ($)
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 4.3			$ 2.3
Expense recognized	(0.7)	$ (0.1)
Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Liability Derivatives	3.9			2.3
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 0.4			0
Natural gas instruments
Derivatives, Fair Value [Line Items]
Notional amount (in MMBtus) | MMBTU	3.2		2.3
Expense recognized	$ 0.7
Net gains to be reclassified from accumulated other comprehensive loss to earnings during the next 12 months	$ 3.2
Natural gas instruments | Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Percent of forecasted usage to be hedged	90%
Maximum period which the company hedges in advance of forecasted purchase	36 months
Natural gas instruments | Derivatives Designated as Hedging Instruments | Accrued expenses and other current liabilities
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 3.5			2.3
Natural gas instruments | Not Designated as Hedging Instrument | Accrued expenses and other current liabilities
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 0.4			$ 0	$ 0.5

Derivative Financial Instrume_4

Derivative Financial Instruments - Schedule of Fair Value of Hedged Items (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023	Mar. 01, 2023
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 0.6	$ 1
Liability Derivatives	4.3	2.3
Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Asset Derivatives	0.6	0.9
Liability Derivatives	3.9	2.3
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset Derivatives	0	0.1
Liability Derivatives	0.4	0
Natural gas instruments
Derivatives, Fair Value [Line Items]
Netting of contracts in a receivable position against contracts in payable position	0.6	1
Other current assets | Natural gas instruments | Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Asset Derivatives	0.3	0.9
Other current assets | Natural gas instruments | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset Derivatives	0	0.1
Other assets | Natural gas instruments | Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Asset Derivatives	0.3
Accrued expenses and other current liabilities | Natural gas instruments | Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Liability Derivatives	3.5	2.3
Accrued expenses and other current liabilities | Natural gas instruments | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Liability Derivatives	0.4	$ 0	$ 0.5
Other noncurrent liabilities | Natural gas instruments | Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 0.4

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Estimated Fair Values (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Dec. 31, 2023	Mar. 31, 2023	Sep. 30, 2023
Common Stock, Large Cap US Companies | Mutual Fund Investments, Concentration Risk | Investment Benchmark
Liability Class:
Investment concentration risk (as a percent)	25%	25%
Common Stock of Small to Mid Cap US Companies | Mutual Fund Investments, Concentration Risk | Investment Benchmark
Liability Class:
Investment concentration risk (as a percent)	5%	5%
Common Stock, International Companies | Mutual Fund Investments, Concentration Risk | Investment Benchmark
Liability Class:
Investment concentration risk (as a percent)	5%	10%
Bond Funds | Mutual Fund Investments, Concentration Risk | Investment Benchmark
Liability Class:
Investment concentration risk (as a percent)	10%	10%
Short-Term Investments | Mutual Fund Investments, Concentration Risk | Investment Benchmark
Liability Class:
Investment concentration risk (as a percent)	5%	5%
Blended Funds | Mutual Fund Investments, Concentration Risk | Investment Benchmark
Liability Class:
Investment concentration risk (as a percent)	50%	45%
Fair Value, Measurements, Recurring
Asset Class:
Mutual fund investments in a non-qualified savings plan	$ 3		$ 2.6
Total Assets	3		2.7
Liability Class:
Derivatives designated as hedging instruments - natural gas instruments, net			(1.4)
Liabilities related to non-qualified savings plan	(3)		(2.6)
Total Liabilities	(6.7)		(4)
Fair Value, Measurements, Recurring | Derivatives Designated as Hedging Instruments
Liability Class:
Derivatives designated as hedging instruments - natural gas instruments, net	(3.3)
Fair Value, Measurements, Recurring | Not Designated as Hedging Instrument
Liability Class:
Derivatives designated as hedging instruments - natural gas instruments, net	(0.4)
Fair Value, Measurements, Recurring | Natural gas instruments, net
Asset Class:
Derivatives not designated as hedging instruments - natural gas instruments, net			0.1
Fair Value, Measurements, Recurring | Level One
Asset Class:
Mutual fund investments in a non-qualified savings plan	3		2.6
Total Assets	3		2.6
Liability Class:
Derivatives designated as hedging instruments - natural gas instruments, net			0
Liabilities related to non-qualified savings plan	(3)		(2.6)
Total Liabilities	(3)		(2.6)
Fair Value, Measurements, Recurring | Level One | Derivatives Designated as Hedging Instruments
Liability Class:
Derivatives designated as hedging instruments - natural gas instruments, net	0
Fair Value, Measurements, Recurring | Level One | Not Designated as Hedging Instrument
Liability Class:
Derivatives designated as hedging instruments - natural gas instruments, net	0
Fair Value, Measurements, Recurring | Level One | Natural gas instruments, net
Asset Class:
Derivatives not designated as hedging instruments - natural gas instruments, net			0
Fair Value, Measurements, Recurring | Level Two
Asset Class:
Mutual fund investments in a non-qualified savings plan	0		0
Total Assets	0		0.1
Liability Class:
Derivatives designated as hedging instruments - natural gas instruments, net			(1.4)
Liabilities related to non-qualified savings plan	0		0
Total Liabilities	(3.7)		(1.4)
Fair Value, Measurements, Recurring | Level Two | Derivatives Designated as Hedging Instruments
Liability Class:
Derivatives designated as hedging instruments - natural gas instruments, net	(3.3)
Fair Value, Measurements, Recurring | Level Two | Not Designated as Hedging Instrument
Liability Class:
Derivatives designated as hedging instruments - natural gas instruments, net	(0.4)
Fair Value, Measurements, Recurring | Level Two | Natural gas instruments, net
Asset Class:
Derivatives not designated as hedging instruments - natural gas instruments, net			0.1
Fair Value, Measurements, Recurring | Level Three
Asset Class:
Mutual fund investments in a non-qualified savings plan	0		0
Total Assets	0		0
Liability Class:
Derivatives designated as hedging instruments - natural gas instruments, net			0
Liabilities related to non-qualified savings plan	0		0
Total Liabilities	0		0
Fair Value, Measurements, Recurring | Level Three | Derivatives Designated as Hedging Instruments
Liability Class:
Derivatives designated as hedging instruments - natural gas instruments, net	0
Fair Value, Measurements, Recurring | Level Three | Not Designated as Hedging Instrument
Liability Class:
Derivatives designated as hedging instruments - natural gas instruments, net	$ 0
Fair Value, Measurements, Recurring | Level Three | Natural gas instruments, net
Asset Class:
Derivatives not designated as hedging instruments - natural gas instruments, net			$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($)	3 Months Ended
	Dec. 31, 2023	Sep. 30, 2023
Fortress
Debt Instrument [Line Items]
Increase to contingent consideration liability	$ 2,900,000
Senior Notes | 6.75% Senior Notes due December 2027
Debt Instrument [Line Items]
Stated interest rate (as a percent)	6.75%	6.75%
Fair value of senior notes	$ 495,000,000	$ 472,500,000
Senior Notes due 2027
Debt Instrument [Line Items]
Debt fair value amount	500,000,000	500,000,000
Term Loan
Debt Instrument [Line Items]
Aggregate principal amount due at maturity	349,900,000	280,300,000
Fair value of credit agreement debt	345,600,000	277,100,000
Fair Value, Measurements, Recurring
Debt Instrument [Line Items]
Mutual fund investments in a non-qualified savings plan	$ 3,000,000	$ 2,600,000

Fair Value Measurements- Schedu

Fair Value Measurements- Schedule of Contingent Consideration (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Asset Acquisition, Contingent Consideration [Line Items]
Total contingent consideration	$ 46.6	$ 43.7
Accrued expenses and other current liabilities
Asset Acquisition, Contingent Consideration [Line Items]
Accrued expenses and other current liabilities	9	8.4
Other noncurrent liabilities
Asset Acquisition, Contingent Consideration [Line Items]
Other noncurrent liabilities	$ 37.6	$ 35.3

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net loss	$ (75.1)	$ (0.3)
Less: net earnings allocated to participating securities	(0.2)	(0.1)
Net loss available to common stockholders	$ (75.3)	$ (0.4)
Denominator (in thousands):
Weighted-average common shares outstanding, shares for basic earnings per share (in shares)	41,205	39,751
Weighted-average awards outstanding (in shares)	0	0
Shares for diluted earnings per share (in shares)	41,205	39,751
Basic net loss per common share (in dollars per share)	$ (1.83)	$ (0.01)
Diluted net loss per common share (in dollars per share)	$ (1.83)	$ (0.01)
Participating securities (in shares)	777,000	514,000
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive weighted options outstanding (in shares)	1,572,000	1,272,000

Related Party Disclosures (Deta

Related Party Disclosures (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	Dec. 20, 2023	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023
Related Party Transaction [Line Items]
Revenue		$ 341.7	$ 352.4
Receivables		168.6		$ 129.5
Accounts payable		85.9		116.8
Cash dividend declared (in dollars per share)	$ 0.15
Payments of dividends		6.4	6.3
Koch Minerals & Trading, LLC
Related Party Transaction [Line Items]
Revenue		0.8	$ 0.9
Receivables		0.6		$ 0.4
Accounts payable		0
Payments of dividends		$ 1.1

Subsequent Events (Details)

Subsequent Events (Details) - Director - Subsequent Event - USD ($)	Jan. 16, 2024	Jan. 15, 2024
Subsequent Event [Line Items]
Consultant rate per month		$ 22,500
Expected cash payments in form of severance payments and benefits	$ 1,600,000	$ 6,300,000
Expected share payments in form of severance payments and benefits		104,597
Expected share payments in form of severance payments and benefits, net of shares for tax withholdings		57,476