Minerals (MTX) 10-K 16 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2017	Feb. 07, 2018	Jul. 02, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	MINERALS TECHNOLOGIES INC
Entity Central Index Key	891,014
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 2.3
Entity Common Stock, Shares Outstanding		35,434,555
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 212.2	$ 188.5
Short-term investments, at cost which approximates market	2.7	2
Accounts receivable, less allowance for doubtful accounts - 2017 - $4.2; 2016 -$ 7.9	383	341.3
Inventories	219.3	186.9
Prepaid expenses	30.1	28
Other current assets	4.9	4.4
Total current assets	852.2	751.1
Property, plant and equipment, less accumulated depreciation and depletion	1,061.3	1,051.8
Goodwill	779.3	778.7
Intangible assets	196.5	204.4
Deferred income taxes	25.6	27.1
Other assets and deferred charges	55.5	50.3
Total assets	2,970.4	2,863.4
Current liabilities:
Short-term debt	6.3	6.1
Current maturities of long-term debt	3.8	6.8
Accounts payable	179	144.9
Income tax payable	8.4	21.5
Accrued compensation and related items	55.4	61.3
Other current liabilities	57.1	54.9
Total current liabilities	310	295.5
Long-term debt, net of unamortized discount and deferred financing costs	959.8	1,069.9
Deferred income taxes	159.4	238.8
Accrued pension and postretirement benefits	155	147.3
Other non-current liabilities	107.1	81
Total liabilities	1,691.3	1,832.5
Shareholders' equity:
Preferred stock, without par value; 1,000,000 shares authorized; none issued	0	0
Common stock, par value at $0.10 per share; 100,000,000 shares authorized; Issued 48,644,736 shares in 2017 and 48,229,826 shares in 2016	4.9	4.8
Additional paid-in capital	422.7	400
Retained earnings	1,607.2	1,419.1
Accumulated other comprehensive loss	(186.1)	(221.1)
Less common stock held in treasury, at cost; 13,270,391 shares in 2017 and 13,259,839 shares in 2016	(597)	(596.3)
Total MTI shareholders' equity	1,251.7	1,006.5
Non-controlling interest	27.4	24.4
Total shareholders' equity	1,279.1	1,030.9
Total liabilities and shareholders' equity	$ 2,970.4	$ 2,863.4

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Accounts receivable, allowance for doubtful accounts	$ 4.2	$ 7.9
Shareholders' equity:
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	48,644,736	48,229,826
Common stock held in treasury, shares (in shares)	13,270,391	13,259,839

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF INCOME [Abstract]
Product sales	$ 1,599	$ 1,552.1	$ 1,615.4
Service revenue	76.7	85.9	182.2
Total net sales	1,675.7	1,638	1,797.6
Cost of goods sold	1,158.5	1,117.7	1,190
Cost of service revenue	50	59.9	136.6
Total cost of sales	1,208.5	1,177.6	1,326.6
Production margin	467.2	460.4	471
Marketing and administrative expenses	182.4	179.4	190.1
Research and development expenses	23.7	23.8	23.6
Acquisition related transaction and integration costs	3.4	8	11.8
Restructuring and other items, net	15	28.3	45.2
Income from operations	242.7	220.9	200.3
Interest expense, net	(43.4)	(54.4)	(60.9)
Extinguishment of debt costs and fees	(3.9)	0	(4.5)
Other non-operating income (deductions), net	(4.5)	3.8	(2.3)
Total non-operating deductions, net	(51.8)	(50.6)	(67.7)
Income from operations before provision for taxes and equity in earnings	190.9	170.3	132.6
Provision (benefit) for taxes on income	(6.6)	35.3	22.8
Equity in earnings of affiliates, net of tax	1.5	2.1	1.8
Consolidated net income	199	137.1	111.6
Less: Net income attributable to non-controlling interests	3.9	3.7	3.7
Net income attributable to Minerals Technologies Inc. (MTI)	$ 195.1	$ 133.4	$ 107.9
Basic:
Income from operations attributable to MTI (in dollars per share)	$ 5.54	$ 3.82	$ 3.11
Diluted:
Income from operations attributable to MTI (in dollars per share)	5.48	3.79	3.08
Cash dividends declared per common share (in dollars per share)	$ 0.20	$ 0.20	$ 0.20
Shares used in computation of earnings per share:
Basic (in shares)	35.2	34.9	34.7
Diluted (in shares)	35.6	35.2	35

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Consolidated net income	$ 199	$ 137.1	$ 111.6
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	44.7	(40.2)	(76.6)
Pension and postretirement plan adjustments	(8.5)	(3.2)	7.3
Unrealized gains on cash flow hedges	0.3	1.6	0
Total other comprehensive income (loss), net of tax	36.5	(41.8)	(69.3)
Total comprehensive income including non-controlling interests	235.5	95.3	42.3
Less: Net income attributable to non-controlling interest	3.9	3.7	3.7
Less: Foreign currency translation adjustments attributable to non-controlling interest	1.5	(1.6)	(1.3)
Comprehensive income attributable to non-controlling interest	5.4	2.1	2.4
Comprehensive income attributable to MTI	$ 230.1	$ 93.2	$ 39.9

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Activities:
Consolidated net income	$ 199	$ 137.1	$ 111.6
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	91	91.9	98.3
Loss on disposal of property, plant and equipment	1.8	1.9	0.1
Deferred income taxes	(76.1)	(10.9)	(2.5)
Pension amortization and settlement loss	7.4	7.9	9.9
Provision for bad debts	3.8	6.2	2.6
Stock-based compensation	8.1	6.3	11.2
Asset impairment charge	5.3	18.5	34.2
Non-cash debt modification costs	1.8	0	0
Other non-cash items	(1.7)	(3.1)	(0.2)
Changes in operating assets and liabilities
Accounts receivable	(27.3)	(4.9)	36.6
Inventories	(25.2)	3.1	3.1
Pension plan funding	(10.8)	(10.5)	(10.4)
Accounts payable	28	(4.8)	(9.7)
Restructuring liabilities	4.5	(4.3)	(3)
Income taxes payable	(12.6)	5.4	(15.4)
Prepaid expenses and other	10.6	(14.7)	3.6
Net cash provided by operating activities	207.6	225.1	270
Investing Activities:
Purchases of property, plant and equipment	(76.7)	(62.4)	(86)
Proceeds from sale of assets	1.4	1.4	5
Purchases of short-term investments	3.8	(6.7)	(4.7)
Proceeds from sale of short-term investments	(4.5)	8	1.1
Other	(1.5)	(1.9)	0
Net cash used in investing activities	(77.5)	(61.6)	(84.6)
Financing Activities:
Proceeds from issuance of long-term debt	0	7.2	11.8
Repayment of long-term debt	(118.9)	(193.2)	(191.8)
Net issuance (repayment) of short-term debt	(0.2)	(0.1)	1.3
Purchase of common shares for treasury	(0.7)	(2.6)	0
Proceeds from issuance of stock under option plan	14.6	5.5	2.5
Excess tax benefits related to stock incentive programs	(3.6)	0.3	0.5
Dividends paid to non-controlling interest	(2.4)	(4.9)	(1.1)
Cash dividends paid	(7)	(7)	(7)
Net cash used in financing activities	(118.2)	(194.8)	(183.8)
Effect of exchange rate changes on cash and cash equivalents	11.8	(9.6)	(21.8)
Net increase (decrease) in cash and cash equivalents	23.7	(40.9)	(20.2)
Cash and cash equivalents at beginning of period	188.5	229.4	249.6
Cash and cash equivalents at end of period	$ 212.2	$ 188.5	$ 229.4

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Millions	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Non-controlling Interests [Member]	Total
Balance at Dec. 31, 2014	$ 4.8	$ 373	$ 1,191.8	$ (112.9)	$ (593.7)	$ 25.9	$ 888.9
Net income	0	0	107.9	0	0	3.7	111.6
Other comprehensive income (loss)	0	0	0	(68)	0	(1.3)	(69.3)
Dividends declared	0	0	(7)	0	0	0	(7)
Dividends to non-controlling interest	0	0	0	0	0	(1.1)	(1.1)
Issuance of shares pursuant to employee stock compensation plans	0	2.4	0	0	0	0	2.4
Income tax benefit arising from employee stock compensation plans	0	1	0	0	0	0	1
Stock-based compensation	0	11.2	0	0	0	0	11.2
Balance at Dec. 31, 2015	4.8	387.6	1,292.7	(180.9)	(593.7)	27.2	937.7
Net income	0	0	133.4	0	0	3.7	137.1
Other comprehensive income (loss)	0	0	0	(40.2)	0	(1.6)	(41.8)
Dividends declared	0	0	(7)	0	0	0	(7)
Dividends to non-controlling interest	0	0	0	0	0	(4.9)	(4.9)
Issuance of shares pursuant to employee stock compensation plans	0	5.5	0	0	0	0	5.5
Income tax benefit arising from employee stock compensation plans	0	0.6	0	0	0	0	0.6
Purchase of common stock for treasury	0	0	0	0	(2.6)	0	(2.6)
Stock-based compensation	0	6.3	0	0	0	0	6.3
Balance at Dec. 31, 2016	4.8	400	1,419.1	(221.1)	(596.3)	24.4	1,030.9
Net income	0	0	195.1	0	0	3.9	199
Other comprehensive income (loss)	0	0	0	35	0	1.5	36.5
Dividends declared	0	0	(7)	0	0	0	(7)
Dividends to non-controlling interest	0	0	0	0	0	(2.4)	(2.4)
Issuance of shares pursuant to employee stock compensation plans	0.1	14.6	0	0	0	0	14.7
Income tax benefit arising from employee stock compensation plans	0	0	0	0	0	0	0
Purchase of common stock for treasury	0	0	0	0	(0.7)	0	(0.7)
Stock-based compensation	0	8.1	0	0	0	0	8.1
Balance at Dec. 31, 2017	$ 4.9	$ 422.7	$ 1,607.2	$ (186.1)	$ (597)	$ 27.4	$ 1,279.1

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Summary of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 1. Summary of Significant Accounting Policies Business The Company is a resource- and technology-based company that develops, produces and markets on a worldwide basis a broad range of specialty mineral, mineral-based and synthetic mineral products and supporting systems and services. Basis of Presentation The accompanying consolidated financial statements include the accounts of Minerals Technologies Inc. (the "Company"), its wholly and majority-owned subsidiaries, as well as variable interest entities for which the Company is the primary beneficiary. All intercompany balances and transactions have been eliminated in consolidation. Use of Estimates The Company employs accounting policies that are in accordance with U.S. generally accepted accounting principles and require management to make estimates and assumptions relating to the reporting of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reported period. Significant estimates include those related to revenue recognition, valuation of long-lived assets, goodwill and other intangible assets, pension plan assumptions, income tax, and litigation and environmental liabilities. Actual results could differ from those estimates. Cash Equivalents and Short-term Investments The Company considers all highly liquid investments with original maturities of three months or less to be cash equivalents. Short-term investments consist of financial instruments, mainly bank deposits, with original maturities beyond three months, but less than twelve months. Short-term investments amounted to $2.7 were no unrealized holding gains and losses on the short-term bank investments held at . Trade Accounts Receivable Trade accounts receivables are recorded at the invoiced amount and do not bear interest. The allowance for doubtful accounts is the Company's best estimate of the amount of probable credit losses in the Company's existing accounts receivable. The Company determines the allowance based on historical write-off experience and specific allowances for bankrupt customers. The Company also analyzes the collection history and financial condition of its other customers, considering current industry conditions and determines whether an allowance needs to be established. The Company reviews its allowance for doubtful accounts monthly. Past due balances over 90 days based on payment terms are reviewed individually for collectability. Account balances are charged off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. The Company does not have any off-balance-sheet credit exposure related to its customers. Inventories Inventories are valued at the lower of cost or market. Cost is determined by the first-in, first-out (FIFO) method. Additionally, items such as idle facility expense, excessive spoilage, freight handling costs, and re-handling costs are recognized as current period charges. The allocation of fixed production overheads to the costs of conversion are based upon the normal capacity of the production facility. Fixed overhead costs associated with idle capacity are expensed as incurred. Property, Plant and Equipment Property, plant and equipment are recorded at cost. Significant improvements are capitalized, while maintenance and repair expenditures are charged to operations as incurred. The Company capitalizes interest cost as a component of construction in progress. The straight-line method of depreciation is used for substantially all of the assets for financial reporting purposes, except for mining related equipment which uses units-of-production method. The annual rates of depreciation are 3% - 6.67% for buildings, 6.67% - 12.5% for machinery and equipment, 8% - 12.5% for furniture and fixtures and 12.5% - 25% for computer equipment and software-related assets. The estimated useful lives of our PCC production facilities and machinery and equipment pertaining to our natural stone mining and processing plants and our chemical plants are 15 years. Property, plant and equipment are depreciated over their useful lives. Useful lives are based on management's estimates of the period that the assets can generate revenue, which does not necessarily coincide with the remaining term of a customer's contractual obligation to purchase products made using those assets. The Company's sales of PCC are predominantly pursuant to long-term evergreen contracts, initially ten years in length, with paper mills at which the Company operates satellite PCC plants. The terms of many of these agreements have been extended, often in connection with an expansion of the satellite PCC plant. Failure of a PCC customer to renew an agreement or continue to purchase PCC from a Company facility could result in an impairment of assets charge or accelerated depreciation at such facility. Depletion of mineral reserves is determined on a unit-of-extraction basis for financial reporting purposes, based upon proven and probable reserves, and on a percentage depletion basis for tax purposes. Stripping Costs Incurred During Production Stripping costs are those costs incurred for the removal of waste materials for the purpose of accessing ore body that will be produced commercially. Stripping costs incurred during the production phase of a mine are variable costs that are included in the costs of inventory produced during the period that the stripping costs are incurred. Accounting for the Impairment of Long-Lived Assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable, the Company estimates the undiscounted future cash flows (excluding interest), resulting from the use of the asset and its ultimate disposition. If the sum of the undiscounted cash flows (excluding interest) is less than the carrying value, the Company recognizes an impairment loss, measured as the amount by which the carrying value exceeds the fair value of the asset, determined principally using discounted cash flows. Goodwill and Other Intangible Assets Goodwill represents the excess of purchase price and related costs over the value assigned to the net tangible and identifiable intangible assets of businesses acquired. Goodwill is not amortized, but instead assessed for impairment. Intangible assets with estimable useful lives are amortized on a straight-line basis over their respective estimated lives to the estimated residual values, and reviewed for impairment. The Company performs a qualitative assessment for each of its reporting units to determine if the two step process for impairment testing is required. If the Company determines that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, the Company would then evaluate the recoverability of goodwill using a two-step impairment test approach at the reporting unit level. In the first step, the fair value for the reporting unit is compared to its book value including goodwill. In the case that the fair value of the reporting unit is less than book value, a second step is performed which compares the fair value of the reporting unit's goodwill to the book value of the goodwill. The fair value for the goodwill is determined based on the difference between the fair values of the reporting unit and the net fair values of the identifiable assets and liabilities of such reporting unit. If the fair value of the goodwill is less than the book value, the difference is recognized as impairment. Investment in joint ventures The Company uses the equity method of accounting to incorporate the results of its investments in companies in which it has significant influence, but does not control; and cost method of accounting in companies in which it cannot exercise significant control. The Company records the equity in earnings of its investments in joint ventures on a one month lag. At December 31, 2017, the book value of Company’s equity method investment was $16.1 million. The Company had no cost method investments at December 31, 2017. Accounting for Asset Retirement Obligations The Company provides for obligations associated with the retirement of long-lived assets and the associated asset retirement costs. The fair value of a liability for an asset retirement obligation is recognized in the period in which it is incurred if a reasonable estimate of fair value can be made. The associated asset retirement costs are capitalized as part of the carrying amount of the long-lived asset. The Company also provides for legal obligations to perform asset retirement activities where timing or methods of settlement are conditional on future events. The Company also records liabilities related to land reclamation as a part of the asset retirement obligations. The Company mines land for various minerals using a surface-mining process that requires the removal of overburden. In many instances, the Company is obligated to restore the land upon completion of the mining activity. As the overburden is removed, the Company recognizes this liability for land reclamation based on the estimated fair value of the obligation. The obligation is adjusted to reflect the passage of time and changes in estimated future cash outflows. Fair Value of Financial Instruments The recorded amounts of cash and cash equivalents, receivables, short-term borrowings, accounts payable, accrued interest, and variable-rate long-term debt approximate fair value because of the short maturity of those instruments or the variable nature of underlying interest rates. Short-term investments are recorded at cost, which approximates fair market value. Derivative Financial Instruments The Company records derivative financial instruments which are used to hedge certain foreign exchange risk at fair value on the balance sheet. See Note 9 for a full description of the Company's hedging activities and related accounting policies. Revenue Recognition Revenue from sale of products is recognized when title passes to the customer, the customer assumes the risks and rewards of ownership, and collectability is reasonably assured; generally, this occurs when the goods are shipped to the customer. In most of the Company's PCC contracts, the price per ton is based upon the total number of tons sold to the customer during the year. Under those contracts the price billed to the customer for shipments during the year is based on periodic estimates of the total annual volume that will be sold to such customer. Revenues are adjusted at the end of each year to reflect the actual volume sold. The Company also has consignment arrangements with certain customers in our Refractories segment. Revenues for these transactions are recorded when the consigned products are consumed by the customer. Revenue from sales of equipment is recorded upon completion of installation and receipt of customer acceptance. Revenue from services is recorded when the services have been performed and collectability is reasonably assured. Revenue from long-term construction contracts is recorded using the percentage-of-completion method. Progress is generally based upon costs incurred to date as compared to the total estimated costs to complete the work under the contract or the amount of product installed in relation to the total amount expected to be installed. All known or anticipated losses on contracts are provided when they become evident. Cost adjustments that are in the process of being negotiated with customers for extra work or changes in scope of work are included in revenue when collection is reasonably assured. Foreign Currency The assets and liabilities of the Company's international subsidiaries are translated into U.S. dollars using exchange rates at the respective balance sheet date. The resulting translation adjustments are recorded in accumulated other comprehensive income (loss) in shareholders' equity. Income statement items are generally translated at monthly average exchange rates prevailing during the period. International subsidiaries operating in highly inflationary economies translate non-monetary assets at historical rates, while net monetary assets are translated at current rates, with the resulting translation adjustments included in net income. At December 31, 2017, the Company had no international subsidiaries operating in highly inflationary economies. Income Taxes Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates in effect for the year in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The Company operates in multiple taxing jurisdictions, both within the U.S. and outside the U.S. In certain situations, a taxing authority may challenge positions that the Company has adopted in its income tax filings. The Company regularly assesses its tax position for such transactions and includes reserves for those differences in position. The reserves are utilized or reversed once the statute of limitations has expired or the matter is otherwise resolved. The application of income tax law is inherently complex. Laws and regulations in this area are voluminous and are often ambiguous. As such, we are required to make many subjective assumptions and judgments regarding our income tax exposures. Interpretations of and guidance surrounding income tax laws and regulations change over time. As such, changes in our subjective assumptions and judgments can materially affect amounts recognized in the consolidated balance sheets and statements of operations. The Company's accounting policy is to recognize interest and penalties as part of its provision for income taxes. See Note 5 for additional detail on our uncertain tax positions. The accompanying financial statements do not include a provision for foreign withholding taxes on international subsidiaries' unremitted earnings, which are expected to be permanently reinvested overseas. Research and Development Research and development costs are expensed as incurred. Accounting for Stock-Based Compensation The Company recognizes compensation expense for share-based awards based upon the grant date fair value over the vesting period. Pension and Post-retirement Benefits The Company has defined benefit pension plans covering the majority of its employees. The benefits are generally based on years of service and an employee's modified career earnings. The Company also provides post-retirement healthcare benefits for the majority of its retirees and employees in the United States. The Company measures the costs of its obligation based on its best estimate. The net periodic costs are recognized as employees render the services necessary to earn the post-retirement benefits. Environmental Expenditures that relate to current operations are expensed or capitalized as appropriate. Expenditures that relate to an existing condition caused by past operations and which do not contribute to current or future revenue generation are expensed. Liabilities are recorded when it is probable the Company will be obligated to pay amounts for environmental site evaluation, remediation or related costs, and such amounts can be reasonably estimated. Earnings Per Share Basic earnings per share have been computed based upon the weighted average number of common shares outstanding during the period. Diluted earnings per share have been computed based upon the weighted average number of common shares outstanding during the period assuming the issuance of common shares for all potentially dilutive common shares outstanding. Subsequent Events The Company has evaluated for subsequent events through the date of issuance of its financial statements. Recently Issued Accounting Standards Changes to accounting principles generally accepted in the United States of America (U.S. GAAP) are established by the Financial Accounting Standards Board (FASB) in the form of accounting standards updates (ASUs) to the FASB’s Accounting Standards Codification. The Company considers the applicability and impact of all ASUs. ASUs not listed below were assessed and determined to be either not applicable or are expected to have minimal impact on our consolidated financial position and results of operations. Revenue from Contracts with Customers In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers” which will supersede nearly all existing revenue recognition guidance under U.S. GAAP. The underlying principle is that an entity will recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. The guidance provides a five-step analysis of transactions to determine when and how revenue is recognized. Other major provisions include capitalization of certain contract costs, consideration of time value of money in the transaction price, and allowing estimates of variable consideration to be recognized before contingencies are resolved in certain circumstances. The guidance also requires enhanced disclosures regarding the nature, amount, timing and uncertainty of revenue and cash flows arising from an entity’s contracts with customers. The guidance is effective for the interim and annual periods beginning on or after December 15, 2017. The guidance permits the use of either a retrospective or cumulative effect transition method. The Company has completed its evaluation of the provisions of this standard and we have concluded that our adoption of ASU No. 2014-09 will not materially change the amount or timing of revenues recognized by us, nor will it materially affect our financial position. We have adopted this new standard effective January 1, 2018. The Company has elected to use the cumulative effect transition method and there will not be a change to our previously reported financial results. Leases In February 2016, the FASB issued ASU 2016-02, “Leases”, which requires lessees to recognize most leases on-balance sheet, thereby increasing their reported assets and liabilities, in some cases very significantly. Lessor accounting remains substantially similar to current U.S. GAAP. ASU 2016-02 is effective for public business entities for annual and interim periods in fiscal years beginning after December 15, 2018. ASU 2016-02 mandates a modified retrospective transition method for all entities. The Company is currently evaluating the impact of this ASU on the Company’s consolidated financial statements and related disclosures. Based on the current status of this assessment, the adoption of this guidance is not expected to have a material impact on the Company’s financial statements. Intangibles – Goodwill and Other In January 2017, the FASB issued ASU 2017-04, “Intangibles-Goodwill and Other: Simplifying the Test for Goodwill Impairment”, which no longer requires an entity to perform a hypothetical purchase price allocation to measure goodwill impairment. Instead, goodwill will be measured using the difference between the carrying amount and the fair value of the reporting unit. The guidance is effective for the interim and annual periods beginning on or after December 15, 2019, with early adoption permitted. The adoption of this guidance is not expected to have a material impact on the Company’s financial statements. Compensation – Retirement Benefits In March 2017, the FASB issued ASU 2017-07, “Compensation – Retirement Benefits: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost”, which requires companies to present the service cost component of the net benefit cost in the same line items in which they report compensation cost. All other components of net periodic benefit cost will be presented outside operating income. The guidance is effective for the interim and annual periods beginning on or after December 15, 2017. We adopted this new standard effective January 1, 2018. The adoption of this guidance is not expected to have a material impact on the Company’s financial statements. Derivatives and Hedging In August 2017, the FASB issued accounting guidance to improve and simplify existing guidance to allow companies to better reflect their risk management activities in the financial statements. The guidance expands the ability to hedge nonfinancial and financial risk components, eliminates the requirement to separately measure and recognize hedge ineffectiveness and eases requirements of an entity’s assessment of hedge effectiveness. The adoption of this guidance is not expected to have a material impact on the Company’s financial statements. Adoption of ASU 2016-09, Stock Compensation- Improvements to Employee Share-Based Payment Accounting On January 1, 2017, the Company adopted the provisions of ASU 2016-09, “Stock Compensation – Improvements to Employee Share-Based Payment Accounting”, an amendment to account standards codification (“ASC”) 718, which simplifies several aspects of accounting for share-based payments, including accounting for income taxes, forfeitures, statutory withhold rates as well as presentation on the statement of cash flows. The Company has elected to adopt the standard on a prospective basis. As a result of this adoption, the Company recognizes excess tax benefits in the current account period. The cash flow benefit of the excess tax benefit is included as an operating activity in the Consolidated Statement of Cash Flows for the period ended December 31, 2017. Additionally, taxes paid for shares withheld for tax-withholding purposes are reported as financing activities in the Condensed Consolidated Statements of Cash Flows. Previously, this activity was included in operating activities. Prior year Condensed Consolidated Statement of Cash Flows has not been restated. In accordance with the standard, the Company will continue to account for forfeitures using an estimated forfeiture rate.

Restructuring and Other Items,

Restructuring and Other Items, net	12 Months Ended
	Dec. 31, 2017
Restructuring and Other Items, net [Abstract]
Restructuring and Other Items, net	Note 2. Restructuring and Other Items, net In 2015, the Company recognized impairment charges for certain underutilized coiled tubing equipment within the Energy Services segment which have been abandoned by the Company. In 2016, the Company recognized additional restructuring charges for lease termination costs, inventory write-offs and impairment of assets relating to its exit from the Nitrogen and Pipeline product lines and restructuring of other onshore services within the Energy Services segment as a result of the significant reduction in oil prices and overcapacity in the onshore oil service market. The Company expects to realize further annualized savings from this restructuring program of $11.5 million (unaudited). In addition, the Company recognized a $2.9 million gain on previously impaired assets in the Refractories and Energy Services Segments. In 2017, the Company recognized $15.0 million in restructuring and non-cash impairment charges from the closure of paper mills in North America, as well as the alignment of corporate and Paper PCC staffing levels into higher growth regions. The restructuring is expected to result in approximately $6 million (unaudited) in savings on an annualized basis. The following table outlines the amount of restructuring charges recorded within the Consolidated Statements of Income, and the segments they relate to: Restructuring and Other Items, net Year Ended December 31, 2017 2017 2016 2015 (millions of dollars) Impairment of assets Specialty Minerals $ 5.3 $ - $ - Performance Materials - - - Energy Services - 18.5 33.0 Corporate - - 1.2 Total impairment of assets charges $ 5.3 $ 18.5 $ 34.2 Severance and other employee costs Specialty Minerals $ 5.0 $ - $ - Performance Materials - - - Refractories - - 2.0 Energy Services 1.7 12.7 9.0 Corporate 4.1 - - Total severance and other employee costs $ 10.8 $ 12.7 $ 11.0 Other Refractories $ - $ (2.0 ) $ - Energy Services (1.1 ) (0.9 ) - Total restructuring and other items, net $ 15.0 $ 28.3 $ 45.2 At December 31, 2017 and 2016, the Company had $8.1 million and $3.6 million, respectively, included within other current liabilities within our Consolidated Balance Sheets for cash expenditures needed to satisfy remaining obligations under these reorganization initiatives. The Company expects to pay these amounts by the end of 2018. The following table is a reconciliation of our restructuring liability balance: (millions of dollars) Restructuring liability, December 31, 2016 $ 3.6 Additional provisions 10.8 Cash payments (6.3 ) Restructuring liability, December 31, 2017 $ 8.1

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2017
Stock-Based Compensation [Abstract]
Stock-Based Compensation	Note 3. Stock-Based Compensation At the Company’s 2015 Annual Meeting of Stockholders, the Company’s stockholders ratified the adoption of the Company’s 2015 Stock Award and Incentive Plan (the “2015 Plan”), which provides for grants of incentive and non-qualified stock options, restricted stock, stock appreciation rights, stock awards or performance unit awards. The 2015 Plan is substantially similar to the Company’s 2001 Stock Award and Incentive Plan (as amended and restated as of March 18, 2009, the “2001 Plan” and collectively with the 2015 Plan, the “Plans”). The Company established the 2015 Plan to increase the total number of shares of common stock reserved and available for issuance by 880,000 shares from the number of shares remaining under the 2001 Plan. With the ratification of the 2015 Plan by the Company’s stockholders, the 2001 Plan was discontinued as to new grants (however, all awards previously granted under the 2001 Plan remained unchanged). The Plans are administered by the Compensation Committee of the Board of Directors. Stock options granted under the Plans generally have a ten year term. The exercise price for stock options are at prices at or above the fair market value of the common stock on the date of the grant, and each award of stock options will vest ratably over a specified period, generally three years. Stock-based compensation expense is recognized in the consolidated financial statements for stock options based on the grant date fair value. Net income for years ended 2017, 2016 and 2015 include $4.1 million, $ million was $1.1 million, $ Stock Options The fair value of options granted is estimated on the date of grant using the Black-Scholes valuation model. Compensation expense is recognized only for those options expected to vest, with forfeitures estimated at the date of grant based on the Company's historical experience and future expectations. The forfeiture rate assumption used for the periods ended December 31, 2017, 2016 and 2015 was 8.71%, 7.38% and 7. The weighted average grant date fair value for stock options granted during the years ended December 31, 2017, 2016 and 2015 was $30.28, $ $ and $ was $11.7 million, $ million The fair value for stock awards was estimated at the date of grant using the Black-Scholes option valuation model with the following weighted average assumptions for the years ended December 31, 2017, 2016 and 2015: 2017 2016 2015 Expected life (in years) 6.4 6.5 6.4 Interest rate 2.04 % 1.72 % 1.52 % Volatility 36.61 % 36.75 % 36.86 % Expected dividend yield 0.26 % 0.54 % 0.33 % The expected term of the options represents the estimated period of time until exercise and is based on historical experience of similar awards, based upon contractual terms, vesting schedules, and expectations of future employee behavior. The expected stock-price volatility is based upon the historical and implied volatility of the Company's stock. The interest rate is based upon the implied yield on U.S. Treasury bills with an equivalent remaining term. Estimated dividend yield is based upon historical dividends paid by the Company. The following table summarizes stock option activity for the year ended December 31, 2017: Awards Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Life (Years) Aggregate Intrinsic Value (Millions) Awards outstanding at December 31, 2016 1,198,725 $ 41.66 Granted 187,533 77.99 Exercised (353,636 ) 41.56 Canceled (35,783 ) 50.47 Awards outstanding at December 31, 2017 996,839 $ 48.21 6.32 $ 22.2 Awards exercisable at December 31, 2017 596,446 $ 41.01 4.94 $ 16.6 The aggregate intrinsic value above is calculated before applicable income taxes, based on the Company's closing stock price of as of the last business day of the period ended had all options been exercised on that date. The weighted average intrinsic value of the options exercised during 2017, was $32.95, $ and $32.07 per share, respectively. As of , total unrecognized stock-based compensation expense related to non-vested stock options was approximately $ million, which is expected to be recognized over a weighted average period of approximately three years. The Company issues new shares of common stock upon the exercise of stock options Non-vested stock option activity for the year ended is as follows: Awards Weighted Average Grant date Fair Value Per Share Nonvested awards outstanding at December 31, 2016 431,412 $ 45.61 Granted 187,533 77.99 Vested (183,679 ) 48.78 Canceled (34,873 ) 50.08 Nonvested awards outstanding at December 31, 2017 400,393 $ 58.94 Restricted Stock The Company has granted key employees rights to receive shares of the Company's common stock pursuant to the Plan. The rights will be deferred for a specified number of years of service, subject to restrictions on transfer and other conditions. Compensation expense for these shares is recognized over the vesting period . The Company granted 69,539 shares, 155,165 shares and 216,502 shares for the periods ended , , respectively. The fair value was determined based on the market value of unrestricted shares. As of , there was unrecognized stock-based compensation related to restricted stock of $5.1 million, which will be recognized over approximately the next three years. The compensation expense amortized with respect to all units was approximately $5.9 million, $5.8 million and $8.8 million for the periods ended , , respectively. In addition, the Company recorded reversals of $2.4 million, $3.8 million and $1.6 million for periods ended , , respectively, related to restricted stock forfeitures. Such costs and reversals are included in marketing and administrative expenses. The following table summarizes the restricted stock activity for the Plan: Awards Weighted Average Grant Date Fair Value Per Share Unvested balance at December 31, 2016 227,213 $ 49.57 Granted 69,539 78.00 Vested (61,274 ) 52.51 Canceled (55,368 ) 52.74 Unvested balance at December 31, 2017 180,110 $ 58.57

Earnings Per Share (EPS)

Earnings Per Share (EPS)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share (EPS) [Abstract]
Earnings Per Share (EPS)	Note 4. Earnings Per Share (EPS) Year Ended December 31, 2017 2016 2015 (in millions, except per share data) Net income attributable to MTI $ 195.1 $ 133.4 $ 107.9 Weighted average shares outstanding 35.2 34.9 34.7 Dilutive effect of stock options and stock units 0.4 0.3 0.3 Weighted average shares outstanding, adjusted 35.6 35.2 35.0 Basic earnings per share attributable to MTI $ 5.54 $ 3.82 $ 3.11 Diluted earnings per share attributable to MTI $ 5.48 $ 3.79 $ 3.08 Options to purchase 181,003 shares, 784 shares and 386,766 shares of common stock for the years ended December 31, 2017, 2016 and 2015 In the first quarter of 2017, the Company adopted the provisions of ASU 2016-09, “ Stock Compensation – Improvements to Employee Share-Based Payment Accounting”.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Income Taxes	Note 5. Income Taxes The U.S. Tax Cuts and Jobs Act (“U.S. Tax Reform”), enacted in December 2017, significantly changes U.S. corporate income tax laws by, among other things, reducing the U.S. corporate income tax rate to 21% starting in 2018 and creating a territorial tax system with a one-time mandatory tax on previously deferred foreign earnings of U.S. subsidiaries. Under U.S. GAAP (specifically, ASC Topic 740), the effects of changes in tax rates and laws on deferred tax balances are recognized in the period in which the new legislation is enacted. In response to U.S. Tax Reform, the Staff of the U.S. Securities and Exchange Commission issued Staff Accounting Bulletin No. 118 (“SAB No. 118”) to provide guidance to registrants in applying ASC Topic 740 in connection with U.S. Tax Reform. SAB No. 118 provides that in the period of enactment, the income tax effects of U.S. Tax Reform may be reported as a provisional amount based on a reasonable estimate (to the extent a reasonable estimate can be determined), which would be subject to adjustment during a “measurement period.” The measurement period begins in the reporting period of the U.S. Tax Reform enactment date and ends when a registrant has obtained, prepared and analyzed the information that was needed in order to complete the accounting requirements under ASC Topic 740. SAB No. 118 also describes supplemental disclosure that should accompany the provisional amounts. U.S. Tax Reform represents the first significant change in U.S. tax law in over 30 years. As permitted by SAB No. 118, some elements of the tax expense recorded in the fourth quarter of 2017 due to the enactment of U.S. Tax Reform are based on reasonable estimates and considered provisional. The Company is continuing to collect and analyze detailed information about the earnings and profits of its non-U.S. subsidiaries, the related taxes paid, the amounts which could be repatriated, the foreign taxes which may be incurred on repatriation and the associated impact of these items under U.S. Tax Reform. The Company may record adjustments to refine those estimates during the measurement period, as additional analysis is completed. As a result, we have recorded a net tax benefit of $47.3 million during the fourth quarter of 2017. This amount, which is reflected within the provision for income taxes in the Consolidated Statement of Income, includes the estimated impact of the one-time mandatory tax on previously deferred earnings of non-U.S. subsidiaries offset in part by the benefit from revaluation of net deferred tax liabilities based on the new lower corporate income tax rate. The impact of the U.S. Tax Reform may differ from this estimate, possibly materially, due to, among other things, changes in interpretations and assumptions made, additional guidance that may be issued and actions taken by the Company as a result of the U.S. Tax Reform. Income from operations before provision for taxes by domestic and foreign source is as follows: 2017 2016 2015 (millions of dollars) Income from continuing operations before income taxes and income from affiliates and joint ventures: Domestic $ 96.7 $ 72.9 $ 32.6 Foreign 94.2 97.4 100.0 $ 190.9 $ 170.3 $ 132.6 The provision (benefit) for taxes on income consists of the following: 2017 2016 2015 (millions of dollars) Domestic Taxes currently payable Federal $ 46.0 $ 18.7 $ 1.4 State and local 2.4 4.4 1.2 Deferred income taxes (78.1 ) (8.8 ) (3.2 ) Domestic tax provision (benefit) (29.7 ) 14.3 (0.6 ) Foreign Taxes currently payable 21.1 23.2 22.7 Deferred income taxes 2.0 (2.2 ) 0.7 Foreign tax provision 23.1 21.0 23.4 Total tax provision (benefit) $ (6.6 ) $ 35.3 $ 22.8 The provision (benefit) for taxes on income shown in the previous table is classified based on the location of the taxing authority, regardless of the location in which the taxable income is generated. The major elements contributing to the difference between the U.S. federal statutory tax rate and the consolidated effective tax rate are as follows: 2017 2016 2015 U.S. statutory rate 35.0 % 35.0 % 35.0 % Depletion (6.7 )% (6.6 )% (8.4 )% Difference between tax provided on foreign earnings and the U.S. statutory rate (3.8 )% (6.4 )% (8.3 )% State and local taxes, net of federal tax benefit 1.1 % 1.1 % 0.3 % Tax credits and foreign dividends 0.3 % 0.6 % (0.5 )% Change in valuation allowance (1.9 )% (1.1 )% (0.9 )% Impact of uncertain tax positions 0.4 % 0.4 % (0.1 )% Impact of officer's non-deductible compensation 0.8 % 0.1 % 2.9 % Manufacturing deduction (1.6 )% (2.0 )% (2.0 )% Impact of US Tax Reform (24.8 )% 0.0 % 0.0 % Other (2.3 )% (0.4 )% (0.8 )% Consolidated effective tax rate (3.5 )% 20.7 % 17.2 % The Company believes that its accrued liabilities are sufficient to cover its U.S. and foreign tax contingencies. The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities are presented below: 2017 2016 (millions of dollars) Deferred tax assets attributable to: Accrued liabilities $ 28.6 $ 49.7 Net operating loss carry forwards 33.2 34.6 Pension and post-retirement benefits costs 40.4 55.4 Other 22.0 35.0 Valuation allowance (21.4 ) (24.8 ) Total deferred tax assets 102.8 149.9 Deferred tax liabilities attributable to: Plant and equipment, principally due to differences in depreciation 161.6 251.3 Intangible assets 63.4 96.3 Other 11.6 14.0 Total deferred tax liabilities 236.6 361.6 Net deferred tax asset (liability) $ (133.8 ) $ (211.7 ) Net deferred tax assets and net deferred tax liabilities are as follows: 2017 2016 (millions of dollars) Net deferred tax asset, long-term $ 25.6 $ 27.1 Net deferred tax liability, long-term 159.4 238.8 Net deferred tax asset (liability), long-term $ (133.8 ) $ (211.7 ) The Company has $33.2 million of deferred tax assets arising from tax loss carry forwards which will be realized through future operations. Carry forwards of approximately $15.5 million expire over the next 20 years, and $17.7 million can be utilized over an indefinite period. On December 31, 2017, the Company had $14.7 million of total unrecognized tax benefits. Included in this amount were a total of $11.9 million of unrecognized income tax benefits that, if recognized, would affect the Company's effective tax rate. While it is expected that the amount of unrecognized tax benefits will change in the next 12 months, we do not expect the change to have a significant impact on the results of operations or the financial position of the Company. The following table summarizes the activity related to our unrecognized tax benefits: 2017 2016 (millions of dollars) Balance at beginning of the year $ 13.7 $ 4.0 Increases related to current year tax positions 1.2 8.8 Increases related to new judgements 1.2 0.9 Decreases related to audit settlements and statue expirations (1.4 ) - Balance at the end of the year $ 14.7 $ 13.7 The Company's accounting policy is to recognize interest and penalties accrued, relating to unrecognized income tax benefits as part of its provision for income taxes. The Company had recorded a $0.4 million benefit in interest and penalties during 2017 and had a total accrued balance on December 31, 2017 of $1.7 million. The Company operates in multiple taxing jurisdictions, both within and outside the U.S. In certain situations, a taxing authority may challenge positions that the Company has adopted in its income tax filings. The Company, with a few exceptions (none of which are material), is no longer subject to U.S. federal, state, local, and European income tax examinations by tax authorities for years prior to 2010. Net cash paid for income taxes were $47.7 million, $30.6 The Company had approximately $531.2 million of foreign subsidiaries' undistributed earnings as of permanently reinvest these earnings overseas for the foreseeable future and while U.S. federal tax expense as been recognized as a result of U.S. Tax Reform, no deferred tax liabilities with respect to foreign withholding taxes or state taxes have been recognized.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2017
Inventories [Abstract]
Inventories	Note 6. Inventories The following is a summary of inventories by major category: 2017 2016 (millions of dollars) Raw materials $ 82.5 $ 70.6 Work-in-process 7.9 5.4 Finished goods 92.3 80.5 Packaging and supplies 36.6 30.4 Total inventories $ 219.3 $ 186.9

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Note 7. Property, Plant and Equipment The major categories of property, plant and equipment and accumulated depreciation and depletion are presented below: December 31, 2017 2016 (millions of dollars) Mineral rights and reserves $ 545.9 $ 547.8 Land 44.5 42.7 Buildings 199.6 195.6 Machinery and equipment 1,247.5 1,193.6 Furniture and fixtures and other 132.3 123.3 Construction in progress 49.8 38.4 2,219.6 2,141.4 Less: accumulated depreciation and depletion (1,158.3 ) (1,089.6 ) Property, plant and equipment, net $ 1,061.3 $ 1,051.8 Depreciation and depletion expense for the years ended December 31, 2017, 2016 and 2015 was $75.6 million, $75.4 million and $82.1 million, respectively.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill and Other Intangible Assets [Abstract]
Goodwill and Other Intangible Assets	Note 8. Goodwill and Other Intangible Assets Goodwill and other intangible assets with indefinite lives are not amortized, but instead are assessed for impairment, at least annually. The carrying amount of goodwill was $779.3 million and $778.7 million as of December 31, 2017 and December 31, 2016, respectively. The net change in goodwill since December 31, 2016 was attributable to the effects of foreign exchange. The balance of goodwill by segment and the activity occurring in the past two fiscal years is as follows: Specialty Minerals Refractories Performance Materials Consolidated (millions of dollars) Balance at December 31, 2015 $ 13.3 $ 47.0 $ 720.9 $ 781.2 Change in goodwill relating to: Foreign exchange translation (1.2 ) (1.3 ) - (2.5 ) Total Changes $ (1.2 ) $ (1.3 ) $ - $ (2.5 ) Balance at December 31, 2016 $ 12.1 $ 45.7 $ 720.9 $ 778.7 Change in goodwill relating to: Foreign exchange translation 0.6 - 0.6 Total Changes 0.6 - - 0.6 Balance at December 31, 2017 $ 12.7 $ 45.7 $ 720.9 $ 779.3 Acquired intangible assets subject to amortization as of December 31, 2017 and December 31, 2016 December 31, 2017 December 31, 2016 Weighted Average Useful Life (Years) Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization (millions of dollars) Tradenames 34 $ 199.8 $ 20.7 $ 199.8 $ 15.3 Technology 12 18.8 4.8 18.8 3.6 Patents and trademarks 17 6.4 5.3 6.4 4.8 Customer relationships 30 4.5 2.2 4.5 1.4 28 $ 229.5 $ 33.0 $ 229.5 $ 25.1 The weighted average amortization period of the acquired intangible assets subject to amortization is approximately 28 years. Amortization expense was approximately $8.0 million, $8.2 million and $7.9 million for the years ended December 31, 2017, 2016 and 2015, respectively and is recorded within the Marketing and administrative expenses line within the Consolidated Statements of Income. The estimated amortization expense is $7.9 million annually for 2018-2022, and $157.0 million thereafter.

Derivative Financial Instrument

Derivative Financial Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2017
Derivative Financial Instruments and Hedging Activities [Abstract]
Derivative Financial Instruments and Hedging Activities	Note 9. Derivative Financial Instruments and Hedging Activities As a multinational corporation with operations throughout the world, the Company is exposed to certain market risks. The Company uses a variety of practices to manage these market risks, including, when considered appropriate, derivative financial instruments. The Company's objective is to offset gains and losses resulting from interest rates and foreign currency exposures with gains and losses on the derivative contracts used to hedge them. The Company uses derivative financial instruments only for risk management and not for trading or speculative purposes. By using derivative financial instruments to hedge exposures to changes in interest rates and foreign currencies, the Company exposes itself to credit risk and market risk. Credit risk is the risk that the counterparty will fail to perform under the terms of the derivative contract. When the fair value of a derivative contract is positive, the counterparty owes the Company, which creates credit risk for the Company. When the fair value of a derivative contract is negative, the Company owes the counterparty, and therefore, it does not face any credit risk. The Company minimizes the credit risk in derivative instruments by entering into transactions with major financial institutions. Market risk is the adverse effect on the value of a financial instrument that results from a change in interest rates, currency exchange rates, or commodity prices. The market risk associated with interest rate and forward exchange contracts is managed by establishing and monitoring parameters that limit the types and degree of market risk that may be undertaken. Cash flow hedges: For derivative instruments that are designated and qualify as cash flow hedges, the Company records the effective portion of the gain or loss in accumulated other comprehensive income (loss) as a separate component of shareholders' equity. The Company subsequently reclassifies the effective portion of gain or loss into earnings in the period during which the hedged transaction is recognized in earnings. The Company utilizes interest rate swaps to limit exposure to market fluctuations on floating-rate debt. During the second quarter of 2016, the Company entered into a floating to fixed interest rate swap for an initial aggregate notional amount of $300 million. The notional amount at December 31, 2017 was $200 million. This interest rate swap is designated as a cash flow hedge. The gains and losses associated with this interest rate swap are recorded in accumulated other comprehensive income (loss). The fair value of this swap was an asset of $2.9 million at December 31, 2017 and is recorded in other assets and deferred charges on the Consolidated Balance Sheet. In addition, the Company uses foreign exchange forward contracts to protect against foreign currency exchange rate risks inherent in its forecasted inventory purchases. The Company had 2 Other: The Company is exposed to potential gains or losses from foreign currency fluctuations affecting net investments and earning denominated in foreign currencies. The Company is particularly sensitive to currency exchange rate fluctuations for the following currencies: British pound sterling (GBP), Chinese renminbi (CYN), Euro, Malaysian ringgit (MYR), Polish zloty (PLN), South African Rand (ZAR), Thai baht (THB) and Turkish lira (TRY). When considered appropriate, the Company enters into foreign exchange derivative contracts to mitigate the risk of fluctuations on these exposures. The Company does not designate these contracts for hedge accounting treatment and the changes in fair value of these contracts are recorded in earnings. The Company recorded (gains) losses of $(1.2) million and $0.6 million in other non-operating income (deductions), net within the Consolidated Statements of Income for the years ended 2017 and 2016, respectively. There were no open contracts at December 31, 2017. There were 2 open foreign exchange contracts at December 31, 2016. The fair value of the 2016 foreign exchange contracts was not significant.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2017
Fair Value of Financial Instruments [Abstract]
Fair Value of Financial Instruments	Note 10. Fair Value of Financial Instruments Fair value is an exchange price that would be received for an asset or paid to transfer a liability (exit price) in an orderly transaction between market participants at the measurement date. The Company utilizes market data or assumptions that market participants would use in pricing the asset or liability. The Company follows a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs about which little or no market data exists, therefore requiring an entity to develop its own assumptions. Assets and liabilities measured at fair value are based on one or more of three valuation techniques. The three valuation techniques are as follows: • Market approach - prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities. • Cost approach - amount that would be required to replace the service capacity of an asset or replacement cost. • Income approach - techniques to convert future amounts to a single present amount based on market expectations, including present value techniques, option-pricing and other models. The Company primarily applies the income approach for foreign exchange derivatives for recurring fair value measurements and attempts to utilize valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. The following table sets forth by level within the fair value hierarchy the Company's financial assets and liabilities accounted for at fair value on a recurring basis at the end of each of the past two years. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company's assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. Fair Value Measurements Using Description Asset / (Liability) Balance at 12/31/17 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (millions of dollars) Deferred compensation plan assets $ 12.9 $ - $ 12.9 $ - Supplementary pension plan assets 11.6 - 11.6 - Interest rate swap 2.9 - 2.9 - Fair Value Measurements Using Description Asset / (Liability) Balance at 12/31/17 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (milliions of dollars) Money market funds $ 0.7 $ 0.7 $ - $ - The fair value of investment in the money market funds is determined by quoted prices in active markets and is categorized as Level 1. The fair value of foreign exchange contracts is determined based on inputs that are readily available in public markets or can be derived from information available in publicly quoted markets and are categorized as Level 2. Deferred compensation and supplementary pension plan assets related to the acquisition of AMCOL businesses and are valued using quoted prices for similar assets in active markets. The Company does not have any financial assets or liabilities measured at fair value on a recurring basis categorized as Level 3, except for pension assets discussed in Note 13, and there were no transfers in or out of Level 3 during the year ended . There were also no changes to the Company's valuation techniques used to measure asset and liability fair values on a recurring basis.

Financial Instruments and Conce

Financial Instruments and Concentrations of Credit Risk	12 Months Ended
	Dec. 31, 2017
Financial Instruments and Concentrations of Credit Risk [Abstract]
Financial Instruments and Concentrations of Credit Risk	Note 11. Financial Instruments and Concentrations of Credit Risk The following methods and assumptions were used to estimate the fair value of each class of financial instrument: Cash and cash equivalents, short-term investments, accounts receivable and payable Short-term debt and other liabilities Long-term debt Forward exchange contracts Credit risk The Company's bad debt expense for the years ended December 31, 2017, 2016 and 2015 was $3.8 million,

Long-Term Debt and Commitments

Long-Term Debt and Commitments	12 Months Ended
	Dec. 31, 2017
Long-Term Debt and Commitments [Abstract]
Long-Term Debt and Commitments	Note 12. Long-Term Debt and Commitments The following is a summary of long term debt: December 31, 2017 2016 (millions of dollars) Term Loan Facility- Variable Tranche due February 14, 2024, net of unamortized discount and deferred financing costs of $ 22.7 million and $ 25.8 million $ 655.3 $ 762.3 Term Loan Facility- Fixed Tranche due May 9, 2021, net of unamortized discount and deferred financing costs of $0.5 million and $0.6 million $ 299.5 $ 299.4 Japan Loan Facilities 5.6 5.8 China Loan Facilities 3.2 9.2 Total $ 963.6 $ 1,076.7 Less: Current maturities 3.8 6.8 Long-term debt $ 959.8 $ 1,069.9 On May 9, 2014, in connection with the acquisition of AMCOL International Corporation (“AMCOL”), the Company entered into a credit agreement providing for a $1,560 million senior secured term loan facility (the “Term Facility”) and a $200 million senior secured revolving credit facility (the “Revolving Facility” and, together with the Term Facility, the “Facilities”). On June 23, 2015, the Company entered into an amendment (the “First Amendment”) to the credit agreement to reprice the $1.378 billion then outstanding on the Term Facility. As amended, the Term Facility had a $1.078 billion floating rate tranche and a $300 million fixed rate tranche. On February 14, 2017, the Company entered into an amendment (the “Second Amendment”) to the credit agreement to reprice the $788 million floating rate tranche then outstanding, which extended the maturity and lowered the interest costs by 75 basis points. Following the Second Amendment, the loans outstanding under the floating rate tranche of the Term Facility will mature on February 14, 2024, the loans outstanding under the fixed rate tranche of the Term Facility will mature on May 9, 2021 and the loans outstanding (if any) and commitments under the Revolving Facility will mature and terminate, as the case may be, on May 9, 2019. After the Second Amendment, loans under the floating rate tranche of the Term Facility bear interest at a rate equal to an adjusted LIBOR rate (subject to a floor of 0.75%) plus an applicable margin equal to 2.25% per annum. Loans under the fixed rate tranche of the Term Facility bear interest at a rate of 4.75%. Loans under the Revolving Facility will bear interest at a rate equal to an adjusted LIBOR rate plus an applicable margin equal to 1.75% per annum. Such rates are subject to decrease by up to 25 basis points in the event that, and for so long as, the Company’s net leverage ratio (as defined in the credit agreement) is less than certain thresholds. The floating rate tranche of the Term Facility was issued at par and the fixed rate tranche of the Term Facility was issued at a 0.25% discount in connection with the First Amendment. The variable rate tranche of the Term Facility was issued at a 0.25% discount in connection with the Second Amendment. The variable rate tranche has a 1% required amortization per year. The Company will pay certain fees under the credit agreement, including customary annual administration fees. The loans under the fixed rate tranche of the Term Facility are subject to prepayment premiums in the event of certain prepayments prior to the third anniversary of the effective date of the First Amendment. The obligations of the Company under the Facilities are unconditionally guaranteed jointly and severally by, subject to certain exceptions, all material domestic subsidiaries of the Company (the “Guarantors”) and secured, subject to certain exceptions, by a security interest in substantially all of the assets of the Company and the Guarantors. The credit agreement contains certain customary affirmative and negative covenants that limit or restrict the ability of the Company and its restricted subsidiaries to enter into certain transactions or take certain actions. In addition, the credit agreement contains a financial covenant that requires the Company, if on the last day of any fiscal quarter loans or letters of credit were outstanding under the Revolving Facility (excluding up to $15 million of letters of credit), to maintain a maximum net leverage ratio (as defined in the credit agreement) of, initially, 5.25 to 1.00 for the four fiscal quarter period preceding such day. Such maximum net leverage ratio requirement is subject to decrease during the duration of the facility to a minimum level (when applicable) of 3.50 to 1.00. As of December 31, 2017, there were no loans and $12.9 million in letters of credit outstanding under the Revolving Facility. The Company is in compliance with all the covenants associated with the Revolving Facility as of the end of the period covered by this report. During 2017, the Company repaid $110 million on its Term Facility. The Company has four committed loan facilities for the funding of new manufacturing facilities in China, for a combined 94.8 million RMB and $1.8 million. In December 2016, the Company entered into a committed loan facility in Japan in the amount of 680 million Yen (approximately $6.0 million). As of December 31, 2017, on a combined basis, $8.8 million was outstanding. Principal will be repaid in accordance with the payment schedules ending in 2021. The Company repaid $6.9 million on these loans in 2017. As of December 31, 2017, the Company had $37.1 million in uncommitted short-term bank credit lines, of which approximately $6.3 million was in use. Short-term borrowings as of December 31, 2017 and 2016 were $6.3 million and $6.1 million, respectively. The weighted average interest rate on short-term borrowings outstanding as of December 31, 2017 and December 31, 2016 was 3.9% and 3.7 The aggregate maturities of long-term debt are as follows: $3.8 million in 2018; $0.6 million in 2019; $0.6 million in 2020, $304 million in 2021; $0.0 million in 2022 and $678 million thereafter. During 2017, 2016 and 2015, respectively, the Company incurred interest costs of $45.4 million, $56.5 million and $62.6 million, including $0.2 million, $0.1 million and $0.5 million, respectively, which were capitalized. Interest paid approximated the incurred interest cost.

Benefit Plans

Benefit Plans	12 Months Ended
	Dec. 31, 2017
Benefit Plans [Abstract]
Benefit Plans	Note 13. Benefit Plans Pension Plans and Other Postretirement Benefit Plans The Company and its subsidiaries have pension plans covering the majority of eligible employees on a contributory or non-contributory basis. Benefits under defined benefit plans are generally based on years of service and an employee's career earnings. Employees generally become fully vested after five years. The Company also provides postretirement health care and life insurance benefits for the majority of its U.S. retired employees. Employees are generally eligible for benefits upon retirement and completion of a specified number of years of creditable service. The Company does not pre-fund these benefits and has the right to modify or terminate the plan in the future. The Company’s disclosures for the U.S. plans have been combined with those outside of the U.S. as the international plans do not have significantly different assumptions, and together represent less than 25% of our total benefit obligation. The following table set forth Company's pension obligation and funded status at December 31: Pension Benefits Post-Retirement Benefits 2017 2016 2017 2016 (millions of dollars) Change in benefit obligations: Beginning projected benefit obligation $ 427.9 $ 416.6 $ 9.3 $ 9.3 Service cost 7.9 8.2 0.3 0.3 Interest cost 12.6 13.0 0.3 0.3 Actuarial (gain)/loss 31.5 21.2 (3.0 ) (0.6 ) Benefits paid (20.4 ) (18.3 ) (0.1 ) - Settlements - (0.9 ) Foreign exchange impact 9.6 (11.4 ) 0.1 - Other 0.4 (0.5 ) - Ending projected benefit obligation 469.5 427.9 6.9 9.3 Change in plan assets: Beginning fair value 289.3 282.5 - - Actual return on plan assets 33.8 22.9 - - Employer contributions 10.7 10.5 0.1 - Plan participants' contributions 0.4 0.4 - - Benefits paid (20.4 ) (18.3 ) (0.1 ) - Settlements (0.8 ) (0.5 ) - - Foreign exchange impact 7.2 (8.2 ) - - Ending fair value 320.2 289.3 - - Funded status of the plan $ (149.3 ) $ (138.6 ) $ (6.9 ) $ (9.3 ) Amounts recognized in the consolidated balance sheet consist of: Pension Benefits Post-Retirement Benefits 2017 2016 2017 2016 (millions of dollars) Current liability $ (0.8 ) $ (0.8 ) $ (0.5 ) $ (0.6 ) Non-current liability (148.5 ) (137.8 ) (6.4 ) (8.7 ) Recognized liability $ (149.3 ) $ (138.6 ) $ (6.9 ) $ (9.3 ) The current portion of pension liabilities is included in accrued compensation and related items. Amounts recognized in accumulated other comprehensive income, net of related tax effects, consist of: Pension Benefits Post-Retirement Benefits 2017 2016 2017 2016 (millions of dollars) Net actuarial (gain) loss $ 91.4 $ 82.1 $ (4.1 ) $ (1.7 ) Prior service cost (0.1 ) (0.1 ) (0.7 ) (2.4 ) Amount recognized end of year $ 91.3 $ 82.0 $ (4.8 ) $ (4.1 ) The accumulated benefit obligation for all defined benefit pension plans was $435.4 million and $394.5 million at December 31, 2017 and 2016, respectively. Changes in the Plan assets and benefit obligations recognized in other comprehensive income: Pension Benefits Post-Retirement Benefits 2017 2016 2017 2016 (millions of dollars) Current year actuarial gain (loss) $ (15.8 ) $ (8.7 ) $ 2.6 $ 0.3 Amortization of actuarial (gain) loss 7.2 6.8 (0.2 ) (0.1 ) Amortization of prior service credit (gain) loss - 0.4 (2.3 ) (1.9 ) Total recognized in other comprehensive income $ (8.6 ) $ (1.5 ) $ 0.1 $ (1.7 ) The components of net periodic benefit costs are as follows: Pension Benefits Post-Retirement Benefits 2017 2016 2015 2017 2016 2015 (millions of dollars) Service cost $ 7.9 $ 8.2 $ 10.3 $ 0.3 $ 0.3 $ 0.4 Interest cost 12.6 13.0 15.4 0.3 0.3 0.3 Expected return on plan assets (18.7 ) (18.6 ) (19.7 ) - - - Amortization of prior service cost - 0.6 0.8 (3.1 ) (3.1 ) (3.1 ) Recognized net actuarial (gain) loss 10.8 10.7 12.1 (0.3 ) (0.2 ) (0.1 ) Settlement/curtailment loss - 0.3 - - - - Net periodic benefit cost $ 12.6 $ 14.2 $ 18.9 $ (2.8 ) $ (2.7 ) $ (2.5 ) Unrecognized prior service cost is amortized over the average remaining service period of each active employee. The Company's funding policy for U.S. plans generally is to contribute annually into trust funds at a rate that provides for future plan benefits and maintains appropriate funded percentages. Annual contributions to the U.S. qualified plans are at least sufficient to satisfy regulatory funding standards and are not more than the maximum amount deductible for income tax purposes. The funding policies for the international plans conform to local governmental and tax requirements. The plans' assets are invested primarily in stocks and bonds. The 2018 estimated amortization of amounts in other accumulated comprehensive income are as follows: Pension Benefits Post-Retirement Benefits (millions of dollars) Amortization of prior service credit (gain) loss $ - $ (0.9 ) Amortization of net (gain) loss 11.5 (0.6 ) Total cost to be recognized $ 11.5 $ (1.5 ) Additional Information The weighted average assumptions used to determine net periodic benefit cost in the accounting for the pension benefit plans and other benefit plans for the years ended December 31, 2017, 2016 and 2015 are as follows: 2017 2016 2015 Discount rate 3.56 % 3.88 % 3.71 % Expected return on plan assets 6.61 % 6.89 % 6.89 % Rate of compensation increase 3.01 % 3.03 % 3.04 % The weighted average assumptions used to determine benefit obligations for the pension benefit plans and other benefit plans at December 31, 2017, 2016 and 2015 are as follows: 2017 2016 2015 Discount rate 3.16 % 3.60 % 3.89 % Rate of compensation increase 3.01 % 2.96 % 3.04 % For 2017, 2016 and 2015, the discount rate was based on a Citigroup yield curve of high quality corporate bonds with cash flows matching our plans' expected benefit payments. The expected return on plan assets is based on our asset allocation mix and our historical return, taking into account current and expected market conditions. The actual return on pension assets was approximately 11% in 2017, % in 2016 and 1% in 2015. The Company maintains a self-funded health insurance plan for its retirees. This plan provided that the maximum health care cost trend rate would be %. Effective June 2010, the Company amended its plan to change the eligibility requirement for retirees and revised its plan so that increases in expected health care costs would be borne by the retiree. Plan Assets The Company's pension plan weighted average asset allocation percentages at December 31, 2017 and 2016 by asset category are as follows: Asset Category 2017 2016 Equity securities 56.0 % 60.2 % Fixed income securities 36.2 % 32.7 % Real estate 0.8 % 0.7 % Other 7.0 % 6.4 % Total 100.0 % 100.0 % The Company's pension plan fair values at December 31, 2017 and 2016 by asset category are as follows: Asset Category 2017 2016 (millions of dollars) Equity securities $ 179.2 $ 174.1 Fixed income securities 116.0 94.7 Real estate 2.4 1.9 Other 22.6 18.6 Total $ 320.2 $ 289.3 The following table presents domestic and foreign pension plan assets information at December 31, 2017, 2016 and 2015 (the measurement date of pension plan assets): U.S. Plans International Plans 2017 2016 2015 2017 2016 2015 (millions of dollars) Fair value of plan assets $ 241.9 $ 221.9 $ 213.0 $ 78.3 $ 67.4 $ 69.5 The following table summarizes our defined benefit pension plan assets measured at fair value as of December 31, 2017: Pension Assets Fair Value as of December 31, 2017 Quoted Prices In Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Total (Level 1) (Level 2) (Level 3) (millions of dollars) Equity securities US equities $ 156.1 $ - $ - $ 156.1 Non-US equities 23.1 - - 23.1 Fixed income securities Corporate debt instruments 82.0 34.0 - 116.0 Real estate and other Real estate - - 2.4 2.4 Other 0.2 - 22.4 22.6 Total assets $ 261.4 $ 34.0 $ 24.8 $ 320.2 The following table summarizes our defined benefit pension plan assets measured at fair value as of December 31, 2016: Pension Assets Fair Value as of December 31, 2016 Quoted Prices In Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Total (Level 1) (Level 2) (Level 3) (millions of dollars) Equity securities US equities $ 155.0 $ 0.2 $ - $ 155.2 Non-US equities 18.9 - - 18.9 Fixed income securities Corporate debt instruments 63.4 31.3 - 94.7 Real estate and other Real estate - - 1.9 1.9 Other - 0.2 18.4 18.6 Total assets $ 237.3 $ 31.7 $ 20.3 $ 289.3 U.S. equities Non-U.S. equities Fixed income— Real Estate and other— This class includes assets related to real estate and other assets such as insurance contracts . Asset classified as Level 1 are valued using quoted prices on major stock exchange on which individual assets are traded. Our Level 2 assets are valued using net asset value. The net asset value is quoted on a private market that is not active; however, the unit price is based on the underlying investments that are traded on an active market. Our Level 3 assets are estimated at fair value based on the most recent financial information available for the underlying securities, which are not traded on active market, and represents significant unobservable input. The following is a reconciliation of changes in fair value measurement of plan assets using significant unobservable inputs (Level 3): (millions of dollars) Beginning balance at December 31, 2015 $ 17.9 Purchases, sales, settlements - Actual return on plan assets still held at reporting date 3.0 Foreign exchange impact (0.6 ) Ending balance at December 31, 2016 $ 20.3 Purchases, sales, settlements - Actual return on plan assets still held at reporting date 3.9 Foreign exchange impact 0.5 Ending balance at December 31, 2017 $ 24.7 There were no transfers in or out of Level 3 during the year ended Contributions The Company expects to contribute $ million to its pension plans and $ million to its other post-retirement benefit plan in 2018. Estimated Future Benefit Payments The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid: Pension Benefits Other Benefits (millions of dollars) 2018 $ 22.9 $ 0.5 2019 $ 24.3 $ 0.5 2020 $ 25.5 $ 0.5 2021 $ 25.4 $ 0.5 2022 $ 26.2 $ 0.5 2023-2026 $ 131.6 $ 2.7 Investment Strategies The investment strategy for pension plan assets is to maintain a broadly diversified portfolio designed to both preserve and grow plan assets to meet future plan obligations. The Company's average rate of return on assets from inception through December 31, 2017 was over %. The Company’s assets are strategically allocated among equity, debt and other investments to achieve a diversification level that dampens fluctuations in investment returns. The Company’s long-term investment strategy is an investment portfolio mix of approximately 55%-65% in equity securities, 30%-35% in fixed income securities and 0%-15% in other securities. Savings and Investment Plans The Company maintains a voluntary Savings and Investment Plan (a 401(k) plan) for most non-union employees in the U.S. Within prescribed limits, the Company bases its contribution to the Savings and Investment Plan on employee contributions. The Company's contributions amounted to $5.2 million, $ million and $6.3 million for the years ended December 31, 2017, 2016 and 2015, respectively.

Leases

Leases	12 Months Ended
	Dec. 31, 2017
Leases [Abstract]
Leases	Note 14. Leases The Company has several non-cancelable operating leases, primarily for office space and equipment. Rent expense amounted to approximately $19.3 million, $16.2 million and $19.5 million for the years ended December 31, 2017, 2016 and 2015, respectively. Total future minimum rental commitments under all non-cancelable leases for each of the years 2018 through 2022 and in aggregate thereafter are approximately $ ecember 31, 2017. Total future minimum payments to be received under direct financing leases for each of the years 2018 through 2022 and the aggregate thereafter are approximately: $

Litigation

Litigation	12 Months Ended
	Dec. 31, 2017
Litigation [Abstract]
Litigation	Note 15. Litigation The Company is party to a number of lawsuits arising in the normal course of our business. On May 8, 2013, Armada (Singapore) PTE Limited, an ocean shipping company now in bankruptcy ("Armada") filed a case in federal court in the Northern District of Illinois against AMCOL and certain of its subsidiaries ( Armada (Singapore) PTE Limited v. AMCOL International Corp., et al., United States District Court for the Northern District of Illinois Certain of the Company's subsidiaries are among numerous defendants in a number of cases seeking damages for exposure to silica or to asbestos containing materials. The Company currently has three pending silica cases and 20 pending asbestos cases. To date, 1,493 silica cases and 53 asbestos cases have been dismissed, not including any lawsuits against AMCOL or American Colloid Company dismissed prior to our acquisition of AMCOL. Seven new asbestos cases were filed in 2017, including one that was previously reported on the Company’s 2016 Annual Report on Form 10-K. Four asbestos cases were dismissed during the period. No silica cases were dismissed during the period. Most of these claims do not provide adequate information to assess their merits, the likelihood that the Company will be found liable, or the magnitude of such liability, if any. Additional claims of this nature may be made against the Company or its subsidiaries. At this time management anticipates that the amount of the Company's liability, if any, and the cost of defending such claims, will not have a material effect on its financial position or results of operations. The Company has settled only one silica lawsuit, for a nominal amount, and no asbestos lawsuits to date (not including any that may have been settled by AMCOL prior to completion of the acquisition). We are unable to state an amount or range of amounts claimed in any of the lawsuits because state court pleading practices do not require identifying the amount of the claimed damage. The aggregate cost to the Company for the legal defense of these cases since inception continues to be insignificant. The majority of the costs of defense for these cases, excluding cases against AMCOL or American Colloid, are reimbursed by Pfizer Inc. pursuant to the terms of certain agreements entered into in connection with the Company's initial public offering in 1992. The Company is entitled to indemnification, pursuant to agreement, for sales prior to the initial public offering. Of the 20 pending asbestos cases, 13 of the non-AMCOL cases are subject to indemnification, in whole or in part, because the plaintiffs claim liability based on sales of products that occurred either entirely before the initial public offering, or both before and after the initial public offering. In the six remaining non-AMCOL cases, the plaintiffs have not alleged dates of exposure. The remaining case is an AMCOL case, which makes no allegation with respect to periods of exposure. Our experience has been that the Company is not liable to plaintiffs in any of these lawsuits and the Company does not expect to pay any settlements or jury verdicts in these lawsuits. Environmental Matters On April 9, 2003, the Connecticut Department of Environmental Protection issued an administrative consent order relating to our Canaan, Connecticut, plant where both our Refractories segment and Specialty Minerals segment have operations. We agreed to the order, which includes provisions requiring investigation and remediation of contamination associated with historic use of polychlorinated biphenyls ("PCBs") and mercury at a portion of the site. We have completed the required investigations and submitted several reports characterizing the contamination and assessing site-specific risks. We are awaiting regulators’ approval of the risk assessment report, which will form the basis for a proposal by the Company concerning eventual remediation. We believe that the most likely form of overall site remediation will be to leave the existing contamination in place (with some limited soil removal), encapsulate it, and monitor the effectiveness of the encapsulation. We anticipate that a substantial portion of the remediation cost will be borne by the United States based on its involvement at the site from 1942 – 1964, as historic documentation indicates that PCBs and mercury were first used at the facility at a time of U.S. government ownership for production of materials needed by the military. Pursuant to a Consent Decree entered on October 24, 2014, the United States paid the Company $2.3 million in the 4 th The Company is evaluating options for upgrading the wastewater treatment facilities at its Adams, Massachusetts plant. This work has been undertaken pursuant to an administrative Consent Order originally issued by the Massachusetts Department of Environmental Protection (“DEP”) on June 18, 2002. This order was amended on June 1, 2009 and on June 2, 2010. The amended Order includes the investigation by January 1, 2022 of options for ensuring that the facility's wastewater treatment ponds will not result in unpermitted discharge to groundwater. Additional requirements of the amendment include the submittal by July 1, 2022 of a plan for closure of a historic lime solids disposal area. Preliminary engineering reviews completed in 2005 indicate that the estimated cost of wastewater treatment upgrades to operate this facility beyond 2024 may be between $6 million and $8 million. The Company estimates that the remaining remediation costs would approximate $0.4 million, which has been accrued as of December 31, 2017. The Company and its subsidiaries are not party to any other material pending legal proceedings, other than routine litigation incidental to their businesses.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity [Abstract]
Stockholders' Equity	Note 16. Stockholders' Equity Capital Stock The Company's authorized capital stock consists of 100 million shares of common stock, par value $0.10 per share, of which 35,374,345 shares and 34,969,987 shares Cash Dividends Cash dividends of $ million or $0.20 per common share were paid during 2017. In January 2018, a cash dividend of approximately $ million or $0.05 per share, was Stock Award and Incentive Plan At the Company’s 2015 Annual Meeting of Stockholders, the Company’s stockholders ratified the adoption of the Company’s 2015 Stock Award and Incentive Plan (the “2015 Plan”), which provides for grants of incentive and non-qualified stock options, restricted stock, stock appreciation rights, stock awards or performance unit awards. The 2015 Plan is substantially similar to the Company’s 2001 Stock Award and Incentive Plan (as amended and restated as of March 18, 2009, the “2001 Plan” and collectively with the 2015 Plan, the “Plans”). The Company established the 2015 Plan to increase the total number of shares of common stock reserved and available for issuance by 880,000 shares from the number of shares remaining under the 2001 Plan. With the ratification of the 2015 Plan by the Company’s stockholders, the 2001 Plan was discontinued as to new grants (however, all awards previously granted under the 2001 Plan remained unchanged). The Plans are administered by the Compensation Committee of the Board of Directors. Stock options granted under the Plan have a term not in excess of ten years. The exercise price for stock options will not be less than the fair market value of the common stock on the date of the grant, and each award of stock options will vest ratably over a specified period, generally three years. The following table summarizes stock option and restricted stock activity for the Plans: Stock Options Restricted Shares Shares Available for Grant Shares Weighted Average Exercise Price Per Share ($) Shares Weighted Average Exercise Price Per Share ($) Balance January 1, 2015 996,127 951,079 $ 37.46 175,488 $ 50.56 Authorized 880,000 - - - - Granted (455,275 ) 238,773 60.40 216,502 60.32 Exercised/vested - (74,839 ) 33.12 (59,801 ) 47.51 Canceled 71,113 (23,169 ) 60.22 (47,944 ) 51.43 Balance December 31, 2015 1,491,965 1,091,844 42.29 284,245 58.63 Granted (538,787 ) 383,622 38.59 155,165 38.37 Exercised/vested - (150,944 ) 36.66 (88,746 ) 57.38 Canceled 249,248 (125,797 ) 43.78 (123,451 ) 50.72 Balance December 31, 2016 1,202,426 1,198,725 41.66 227,213 49.57 Granted (257,072 ) 187,533 77.99 69,539 78.00 Exercised/vested - (353,636 ) 41.56 (61,274 ) 52.51 Canceled 91,151 (35,783 ) 50.47 (55,368 ) 52.74 Balance December 31, 2017 1,036,505 996,839 48.21 180,110 58.57

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss)	Note 17. Accumulated Other Comprehensive Income (Loss) Accumulated other comprehensive income (loss) at December 31 comprised of the following components: 2017 2016 (millions of dollars) Cumulative foreign currency translation $ (104.1 ) $ (147.3 ) Unrecognized pension costs (net of tax benefit of $30.7 in 2017 and $39.4 in 2016) (86.5 ) (78.0 ) Unrealized gain (loss) on cash flow hedges (net of tax expense of $0.7 in 2017 and $1.8 in 2016) 4.5 4.2 $ (186.1 ) $ (221.1 ) The following table summarizes the changes in other comprehensive income (loss) by component: Year Ended December 31, 2017 2016 2015 Pre-Tax Amount Tax (Expense) Benefit Net-of- Tax Amount Pre-Tax Amount Tax (Expense) Benefit Net-of- Tax Amount Pre-Tax Amount Tax (Expense) Benefit Net-of- Tax Amount (millions of dollars) Foreign currency translation adjustment $ 44.7 $ - $ 44.7 $ (40.2 ) $ - $ (40.2 ) $ (76.6 ) $ - $ (76.6 ) Pension plans: Net actuarial gains (losses) and prior service costs arising during the period (17.6 ) 4.4 (13.2 ) (12.5 ) 4.1 (8.4 ) 0.5 0.5 1.0 Amortization of net actuarial (gains) losses and prior service costs 7.6 (2.9 ) 4.7 8.0 (2.8 ) 5.2 9.6 (3.3 ) 6.3 Unrealized gains (losses) on cash flow hedges 0.2 0.1 0.3 2.4 (0.8 ) 1.6 - - - Total other comprehensive income (loss) $ 34.9 $ 1.6 $ 36.5 $ (42.3 ) $ 0.5 $ (41.8 ) $ (66.5 ) $ (2.8 ) $ (69.3 ) The pre-tax amortization amounts of pension plans in the table above are included within the components of net periodic pension benefit costs (see Note 13) and the related tax amounts are included within provision (benefit) for taxes on income line within Consolidated Statements of Income.

Accounting for Asset Retirement

Accounting for Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2017
Accounting for Asset Retirement Obligations [Abstract]
Accounting for Asset Retirement Obligations	Note 18. Accounting for Asset Retirement Obligations The Company records asset retirement obligations in which the Company will be required to retire tangible long-lived assets. These are primarily related to its PCC satellite facilities and mining operations. The Company has also recorded the provisions related to conditional asset retirement obligations at its facilities. The Company has recorded asset retirement obligations at all of its facilities except where there are no contractual or legal obligations. The associated asset retirement costs are capitalized as part of the carrying amount of the long-lived asset. The following is a reconciliation of asset retirement obligations as of December 31, 2017 and 2016: 2017 2016 (millions of dollars) Asset retirement liability, beginning of period $ 21.5 $ 21.4 Accretion expense 3.3 2.5 Payments (3.2 ) (1.6 ) Foreign currency translation 0.5 (0.8 ) Asset retirement liability, end of period $ 22.1 $ 21.5 The Company mines various minerals using a surface mining process that requires the removal of overburden. In certain areas and under various governmental regulations, the Company is obligated to restore the land comprising each mining site to its original condition at the completion of the mining activity. This liability will be adjusted to reflect the passage of time, mining activities, and changes in estimated future cash outflows The current portion of the liability of approximately $1.6 million is included in other current liabilities and the long-term portion of the liability of approximately $20.5 million is included in other non-current liabilities in the Consolidated Balance Sheet as of December 31, 2017. Accretion expense is included in cost of goods sold in the Company's Consolidated Statements of Income.

Segment and Related Information

Segment and Related Information	12 Months Ended
	Dec. 31, 2017
Segment and Related Information [Abstract]
Segment and Related Information	Note 19. Segment and Related Information The Company determines its operating segments based on the discrete financial information that is regularly evaluated by its chief operating decision maker, our Chief Executive Officer, in deciding how to allocate resources and in assessing performance. Accordingly, in the first quarter of 2017, the Company reorganized the management structure for its Performance Materials and Construction Technologies business units to better reflect the way performance is evaluated and resources are allocated. As a result, all of the product lines within these business segments were combined into one operating segment. The Company's operating segments are strategic business units that offer different products and serve different markets. They are managed separately and require different technology and marketing strategies. The Company now has four reportable segments: Specialty Minerals, Refractories, Performance Materials and Energy Services. - The Specialty Minerals segment produces and sells the synthetic mineral product precipitated calcium carbonate ("PCC") and processed mineral product quicklime ("lime"), and mines mineral ores then processes and sells natural mineral products, primarily limestone and talc. - The Refractories segment produces and markets monolithic and shaped refractory materials and specialty products, services and application and measurement equipment, and calcium metal and metallurgical wire products. - The Performance Materials segment is a leading global supplier of bentonite and bentonite-related products, chromite and leonardite. This segment also provides products for non-residential construction, environmental and infrastructure projects worldwide, serving customers engaged in a broad range of construction projects. - The Energy Services segment provides services to improve the production, costs, compliance, and environmental impact of activities performed in oil and gas industry. This segment offers a range of services for off-shore filtration and well testing to the worldwide oil and gas industry. The accounting policies of the segments are the same as those described in the summary of significant accounting policies. The Company evaluates performance based on the operating income of the respective business units. The costs deducted to arrive at operating profit do not include several items, such as net interest or income tax expense. Depreciation expense related to corporate assets is allocated to the business segments and is included in their income from operations. However, such corporate depreciable assets are not included in the segment assets. Intersegment sales and transfers are not significant. Segment information for the years ended December 31, 2017, 2016 and 2015 was as follows: 2017 2016 2015 (millions of dollars) Net Sales Specialty Minerals $ 584.8 $ 591.5 $ 624.6 Performance Materials 734.8 686.1 694.9 Refractories 279.4 274.5 295.9 Energy Services 76.7 85.9 182.2 Total 1,675.7 1,638.0 1,797.6 Income from Operations Specialty Minerals 88.9 102.7 100.8 Performance Materials 119.7 121.1 118.4 Refractories 39.8 37.0 27.8 Energy Services 6.1 (25.9 ) (27.9 ) Total 254.5 234.9 219.1 Depreciation, Depletion and Amortization Specialty Minerals 35.5 34.9 34.0 Performance Materials 40.5 38.9 39.4 Refractories 6.8 6.9 7.5 Energy Services 8.2 11.2 17.4 Total 91.0 91.9 98.3 Segment Assets Specialty Minerals 519.4 491.7 505.3 Performance Materials 1,989.6 1,942.1 1,965.4 Refractories 307.4 283.4 292.7 Energy Services 110.6 104.7 154.7 Total 2,927.0 2,821.9 2,918.1 Capital Expenditures Specialty Minerals 32.6 40.4 51.9 Performance Materials 33.1 12.8 11.1 Refractories 5.9 5.9 11.1 Energy Services 4.5 1.4 11.1 Total 76.1 60.5 85.2 A reconciliation of the totals reported for the operating segments to the applicable line items in the consolidated financial statements is as follows: 2017 2016 2015 (millions of dollars) Income from Operations before Provision (Benefit) for Taxes on Income Income from operations for reportable segments $ 254.5 $ 234.9 $ 219.1 Acquisition related transaction and integration costs (3.4 ) (8.0 ) (11.8 ) Unallocated corporate expenses (8.4 ) (6.0 ) (7.0 ) Consolidated income from operations 242.7 220.9 200.3 Non-operating deductions, net (51.8 ) (50.6 ) (67.7 ) Income from continuing operations before provision (benefit) for taxes on income 190.9 170.3 132.6 Total Assets Total segment assets 2,927.0 2,821.9 2,918.1 Corporate assets 43.4 41.5 61.9 Consolidated total assets 2,970.4 2,863.4 2,980.0 Capital Expenditures Total segment capital expenditures 76.1 60.5 85.2 Corporate capital expenditures 0.6 1.9 0.8 Consolidated capital expenditures 76.7 62.4 86.0 Financial information relating to the Company's operations by geographic area was as follows: 2017 2016 2015 (millions of dollars) Net Sales United States $ 939.3 $ 936.2 $ 1,049.6 Canada/Latin America 81.6 82.6 86.3 Europe/Africa 349.0 338.8 382.1 Asia 305.8 280.4 279.6 Total International 736.4 701.8 748.0 Consolidated net sales 1,675.7 1,638.0 1,797.6 Long-Lived Assets United States $ 1,774.4 $ 1,794.5 $ 1,829.3 Canada/Latin America 14.8 14.8 13.0 Europe/Africa 115.9 98.2 117.6 Asia 132.0 127.3 138.3 Total International 262.7 240.3 268.9 Consolidated long-lived assets 2,037.1 2,034.8 2,098.2 Net sales and long-lived assets are attributed to countries and geographic areas based on the location of the legal entity. No individual foreign country represents more than 10% of consolidated net sales or consolidated long-lived asset. The Company's sales by product category are as follows: 2017 2016 2015 (millions of dollars) Paper PCC $ 377.7 $ 387.9 $ 423.3 Specialty PCC 66.0 64.3 64.8 Talc 53.8 55.7 55.9 Ground Calcium Carbonate 87.3 83.6 80.6 Metalcasting 294.3 258.0 266.4 Household, Personal Care & Specialty Products 169.6 171.2 172.7 Basic Minerals 125.0 103.9 106.0 Environmental Products 67.7 78.9 69.8 Building Materials 78.2 74.1 80.0 Refractory Products 226.9 219.0 230.7 Metallurgical Products 52.5 55.5 65.2 Energy Services 76.7 85.9 182.2 Total $ 1,675.7 $ 1,638.0 $ 1,797.6

Quarterly Financial Data (unaud

Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Data (unaudited) [Abstract]
Quarterly Financial Data (unaudited)	Note 20. Quarterly Financial Data (unaudited) 2017 quarters First Second Third Fourth (millions of dollars, except per share amounts) Net sales by segment Specialty Minerals segment $ 146.2 $ 147.0 $ 147.7 $ 143.9 Performance Materials segment 169.9 180.3 188.8 $ 195.8 Refractories segment 70.2 68.9 69.0 $ 71.3 Energy Services segment 18.7 17.9 19.0 $ 21.1 Net sales 405.0 414.1 424.5 432.1 Gross profit 113.7 119.7 119.3 114.5 Income from operations 61.7 68.5 66.8 45.7 Consolidated net income 35.6 43.8 42.8 76.7 Net income attributable to Minerals Technologies Inc. (MTI) 34.6 43.0 41.7 75.8 Basic earnings per share attributable to MTI shareholders $ 0.99 $ 1.23 $ 1.18 $ 2.14 Diluted earnings per share attributable to MTI shareholders $ 0.97 $ 1.21 $ 1.17 $ 2.12 Market price range per share of common stock: High $ 83.70 $ 80.20 $ 75.60 $ 73.55 Low $ 72.20 $ 70.50 $ 62.95 $ 66.40 Close $ 76.60 $ 73.20 $ 70.65 $ 68.85 Dividends paid per common share $ 0.05 $ 0.05 $ 0.05 $ 0.05 2016 quarters First Second Third Fourth (millions of dollars, except per share amounts) Net sales by segment Specialty Minerals segment $ 155.6 $ 150.6 $ 147.3 $ 138.0 Performance Materials segment 159.6 182.5 169.0 175.0 Refractories segment 69.2 73.9 63.4 68.0 Energy Services segment 25.8 20.0 19.8 20.3 Net sales 410.2 427.0 399.5 401.3 Gross profit 112.7 121.1 115.2 111.4 Income from operations 57.6 39.5 67.3 56.5 Consolidated net income 34.8 22.3 42.5 37.5 Net income attributable to MTI 33.9 21.2 41.6 36.7 Basic earnings per share attributable to MTI shareholders $ 0.97 $ 0.61 $ 1.19 $ 1.05 Diluted earnings per share attributable to MTI shareholders $ 0.97 $ 0.60 $ 1.18 $ 1.04 Market price range per share of common stock: High $ 57.12 $ 61.66 $ 72.51 $ 82.90 Low $ 37.03 $ 52.53 $ 56.00 $ 66.10 Close $ 57.12 $ 57.38 $ 70.69 $ 77.25 Dividends paid per common share $ 0.05 $ 0.05 $ 0.05 $ 0.05

SCHEDULE II-VALUATION AND QUALI

SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS	12 Months Ended
	Dec. 31, 2017
SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS [Abstract]
SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS	MINERALS TECHNOLOGIES INC. & SUBSIDIARY COMPANIES SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS (millions of dollars) Description Balance at Beginning of Period Additions Charged to Costs, Provisions and Expenses Deductions (a) Balance at End of Period Year ended December 31, 2017 Valuation and qualifying accounts deducted from assets to which they apply: Allowance for doubtful accounts $ 7.9 3.8 (7.5 ) 4.2 Year ended December 31, 2016 Valuation and qualifying accounts deducted from assets to which they apply: Allowance for doubtful accounts $ 4.4 6.2 (2.7 ) 7.9 Year ended December 31, 2015 Valuation and qualifying accounts deducted from assets to which they apply: Allowance for doubtful accounts $ 3.6 2.6 (1.8 ) 4.4 (a) Includes impact of translation of foreign currencies.

Summary of Significant Accoun29

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Summary of Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include the accounts of Minerals Technologies Inc. (the "Company"), its wholly and majority-owned subsidiaries, as well as variable interest entities for which the Company is the primary beneficiary. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The Company employs accounting policies that are in accordance with U.S. generally accepted accounting principles and require management to make estimates and assumptions relating to the reporting of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reported period. Significant estimates include those related to revenue recognition, valuation of long-lived assets, goodwill and other intangible assets, pension plan assumptions, income tax, and litigation and environmental liabilities. Actual results could differ from those estimates.
Cash Equivalents and Short-term Investments	Cash Equivalents and Short-term Investments The Company considers all highly liquid investments with original maturities of three months or less to be cash equivalents. Short-term investments consist of financial instruments, mainly bank deposits, with original maturities beyond three months, but less than twelve months. Short-term investments amounted to $2.7 were no unrealized holding gains and losses on the short-term bank investments held at .
Trade Accounts Receivable	Trade Accounts Receivable Trade accounts receivables are recorded at the invoiced amount and do not bear interest. The allowance for doubtful accounts is the Company's best estimate of the amount of probable credit losses in the Company's existing accounts receivable. The Company determines the allowance based on historical write-off experience and specific allowances for bankrupt customers. The Company also analyzes the collection history and financial condition of its other customers, considering current industry conditions and determines whether an allowance needs to be established. The Company reviews its allowance for doubtful accounts monthly. Past due balances over 90 days based on payment terms are reviewed individually for collectability. Account balances are charged off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. The Company does not have any off-balance-sheet credit exposure related to its customers.
Inventories	Inventories Inventories are valued at the lower of cost or market. Cost is determined by the first-in, first-out (FIFO) method. Additionally, items such as idle facility expense, excessive spoilage, freight handling costs, and re-handling costs are recognized as current period charges. The allocation of fixed production overheads to the costs of conversion are based upon the normal capacity of the production facility. Fixed overhead costs associated with idle capacity are expensed as incurred.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are recorded at cost. Significant improvements are capitalized, while maintenance and repair expenditures are charged to operations as incurred. The Company capitalizes interest cost as a component of construction in progress. The straight-line method of depreciation is used for substantially all of the assets for financial reporting purposes, except for mining related equipment which uses units-of-production method. The annual rates of depreciation are 3% - 6.67% for buildings, 6.67% - 12.5% for machinery and equipment, 8% - 12.5% for furniture and fixtures and 12.5% - 25% for computer equipment and software-related assets. The estimated useful lives of our PCC production facilities and machinery and equipment pertaining to our natural stone mining and processing plants and our chemical plants are 15 years. Property, plant and equipment are depreciated over their useful lives. Useful lives are based on management's estimates of the period that the assets can generate revenue, which does not necessarily coincide with the remaining term of a customer's contractual obligation to purchase products made using those assets. The Company's sales of PCC are predominantly pursuant to long-term evergreen contracts, initially ten years in length, with paper mills at which the Company operates satellite PCC plants. The terms of many of these agreements have been extended, often in connection with an expansion of the satellite PCC plant. Failure of a PCC customer to renew an agreement or continue to purchase PCC from a Company facility could result in an impairment of assets charge or accelerated depreciation at such facility. Depletion of mineral reserves is determined on a unit-of-extraction basis for financial reporting purposes, based upon proven and probable reserves, and on a percentage depletion basis for tax purposes.
Stripping Costs Incurred During Production	Stripping Costs Incurred During Production Stripping costs are those costs incurred for the removal of waste materials for the purpose of accessing ore body that will be produced commercially. Stripping costs incurred during the production phase of a mine are variable costs that are included in the costs of inventory produced during the period that the stripping costs are incurred.
Accounting for the Impairment of Long-Lived Assets	Accounting for the Impairment of Long-Lived Assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable, the Company estimates the undiscounted future cash flows (excluding interest), resulting from the use of the asset and its ultimate disposition. If the sum of the undiscounted cash flows (excluding interest) is less than the carrying value, the Company recognizes an impairment loss, measured as the amount by which the carrying value exceeds the fair value of the asset, determined principally using discounted cash flows.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill represents the excess of purchase price and related costs over the value assigned to the net tangible and identifiable intangible assets of businesses acquired. Goodwill is not amortized, but instead assessed for impairment. Intangible assets with estimable useful lives are amortized on a straight-line basis over their respective estimated lives to the estimated residual values, and reviewed for impairment. The Company performs a qualitative assessment for each of its reporting units to determine if the two step process for impairment testing is required. If the Company determines that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, the Company would then evaluate the recoverability of goodwill using a two-step impairment test approach at the reporting unit level. In the first step, the fair value for the reporting unit is compared to its book value including goodwill. In the case that the fair value of the reporting unit is less than book value, a second step is performed which compares the fair value of the reporting unit's goodwill to the book value of the goodwill. The fair value for the goodwill is determined based on the difference between the fair values of the reporting unit and the net fair values of the identifiable assets and liabilities of such reporting unit. If the fair value of the goodwill is less than the book value, the difference is recognized as impairment.
Investment in joint ventures	Investment in joint ventures The Company uses the equity method of accounting to incorporate the results of its investments in companies in which it has significant influence, but does not control; and cost method of accounting in companies in which it cannot exercise significant control. The Company records the equity in earnings of its investments in joint ventures on a one month lag. At December 31, 2017, the book value of Company’s equity method investment was $16.1 million. The Company had no cost method investments at December 31, 2017.
Accounting for Asset Retirement Obligations	Accounting for Asset Retirement Obligations The Company provides for obligations associated with the retirement of long-lived assets and the associated asset retirement costs. The fair value of a liability for an asset retirement obligation is recognized in the period in which it is incurred if a reasonable estimate of fair value can be made. The associated asset retirement costs are capitalized as part of the carrying amount of the long-lived asset. The Company also provides for legal obligations to perform asset retirement activities where timing or methods of settlement are conditional on future events. The Company also records liabilities related to land reclamation as a part of the asset retirement obligations. The Company mines land for various minerals using a surface-mining process that requires the removal of overburden. In many instances, the Company is obligated to restore the land upon completion of the mining activity. As the overburden is removed, the Company recognizes this liability for land reclamation based on the estimated fair value of the obligation. The obligation is adjusted to reflect the passage of time and changes in estimated future cash outflows.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The recorded amounts of cash and cash equivalents, receivables, short-term borrowings, accounts payable, accrued interest, and variable-rate long-term debt approximate fair value because of the short maturity of those instruments or the variable nature of underlying interest rates. Short-term investments are recorded at cost, which approximates fair market value.
Derivative Financial Instruments	Derivative Financial Instruments The Company records derivative financial instruments which are used to hedge certain foreign exchange risk at fair value on the balance sheet. See Note 9 for a full description of the Company's hedging activities and related accounting policies.
Revenue Recognition	Revenue Recognition Revenue from sale of products is recognized when title passes to the customer, the customer assumes the risks and rewards of ownership, and collectability is reasonably assured; generally, this occurs when the goods are shipped to the customer. In most of the Company's PCC contracts, the price per ton is based upon the total number of tons sold to the customer during the year. Under those contracts the price billed to the customer for shipments during the year is based on periodic estimates of the total annual volume that will be sold to such customer. Revenues are adjusted at the end of each year to reflect the actual volume sold. The Company also has consignment arrangements with certain customers in our Refractories segment. Revenues for these transactions are recorded when the consigned products are consumed by the customer. Revenue from sales of equipment is recorded upon completion of installation and receipt of customer acceptance. Revenue from services is recorded when the services have been performed and collectability is reasonably assured. Revenue from long-term construction contracts is recorded using the percentage-of-completion method. Progress is generally based upon costs incurred to date as compared to the total estimated costs to complete the work under the contract or the amount of product installed in relation to the total amount expected to be installed. All known or anticipated losses on contracts are provided when they become evident. Cost adjustments that are in the process of being negotiated with customers for extra work or changes in scope of work are included in revenue when collection is reasonably assured.
Foreign Currency	Foreign Currency The assets and liabilities of the Company's international subsidiaries are translated into U.S. dollars using exchange rates at the respective balance sheet date. The resulting translation adjustments are recorded in accumulated other comprehensive income (loss) in shareholders' equity. Income statement items are generally translated at monthly average exchange rates prevailing during the period. International subsidiaries operating in highly inflationary economies translate non-monetary assets at historical rates, while net monetary assets are translated at current rates, with the resulting translation adjustments included in net income. At December 31, 2017, the Company had no international subsidiaries operating in highly inflationary economies.
Income Taxes	Income Taxes Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates in effect for the year in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The Company operates in multiple taxing jurisdictions, both within the U.S. and outside the U.S. In certain situations, a taxing authority may challenge positions that the Company has adopted in its income tax filings. The Company regularly assesses its tax position for such transactions and includes reserves for those differences in position. The reserves are utilized or reversed once the statute of limitations has expired or the matter is otherwise resolved. The application of income tax law is inherently complex. Laws and regulations in this area are voluminous and are often ambiguous. As such, we are required to make many subjective assumptions and judgments regarding our income tax exposures. Interpretations of and guidance surrounding income tax laws and regulations change over time. As such, changes in our subjective assumptions and judgments can materially affect amounts recognized in the consolidated balance sheets and statements of operations. The Company's accounting policy is to recognize interest and penalties as part of its provision for income taxes. See Note 5 for additional detail on our uncertain tax positions. The accompanying financial statements do not include a provision for foreign withholding taxes on international subsidiaries' unremitted earnings, which are expected to be permanently reinvested overseas.
Research and Development	Research and Development Research and development costs are expensed as incurred.
Accounting for Stock-Based Compensation	Accounting for Stock-Based Compensation The Company recognizes compensation expense for share-based awards based upon the grant date fair value over the vesting period.
Pension and Post-retirement Benefits	Pension and Post-retirement Benefits The Company has defined benefit pension plans covering the majority of its employees. The benefits are generally based on years of service and an employee's modified career earnings. The Company also provides post-retirement healthcare benefits for the majority of its retirees and employees in the United States. The Company measures the costs of its obligation based on its best estimate. The net periodic costs are recognized as employees render the services necessary to earn the post-retirement benefits.
Environmental	Environmental Expenditures that relate to current operations are expensed or capitalized as appropriate. Expenditures that relate to an existing condition caused by past operations and which do not contribute to current or future revenue generation are expensed. Liabilities are recorded when it is probable the Company will be obligated to pay amounts for environmental site evaluation, remediation or related costs, and such amounts can be reasonably estimated.
Earnings Per Share	Earnings Per Share Basic earnings per share have been computed based upon the weighted average number of common shares outstanding during the period. Diluted earnings per share have been computed based upon the weighted average number of common shares outstanding during the period assuming the issuance of common shares for all potentially dilutive common shares outstanding.
Subsequent Events	Subsequent Events The Company has evaluated for subsequent events through the date of issuance of its financial statements.
Recently Issued Accounting Standards	Recently Issued Accounting Standards Changes to accounting principles generally accepted in the United States of America (U.S. GAAP) are established by the Financial Accounting Standards Board (FASB) in the form of accounting standards updates (ASUs) to the FASB’s Accounting Standards Codification. The Company considers the applicability and impact of all ASUs. ASUs not listed below were assessed and determined to be either not applicable or are expected to have minimal impact on our consolidated financial position and results of operations. Revenue from Contracts with Customers In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers” which will supersede nearly all existing revenue recognition guidance under U.S. GAAP. The underlying principle is that an entity will recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. The guidance provides a five-step analysis of transactions to determine when and how revenue is recognized. Other major provisions include capitalization of certain contract costs, consideration of time value of money in the transaction price, and allowing estimates of variable consideration to be recognized before contingencies are resolved in certain circumstances. The guidance also requires enhanced disclosures regarding the nature, amount, timing and uncertainty of revenue and cash flows arising from an entity’s contracts with customers. The guidance is effective for the interim and annual periods beginning on or after December 15, 2017. The guidance permits the use of either a retrospective or cumulative effect transition method. The Company has completed its evaluation of the provisions of this standard and we have concluded that our adoption of ASU No. 2014-09 will not materially change the amount or timing of revenues recognized by us, nor will it materially affect our financial position. We have adopted this new standard effective January 1, 2018. The Company has elected to use the cumulative effect transition method and there will not be a change to our previously reported financial results. Leases In February 2016, the FASB issued ASU 2016-02, “Leases”, which requires lessees to recognize most leases on-balance sheet, thereby increasing their reported assets and liabilities, in some cases very significantly. Lessor accounting remains substantially similar to current U.S. GAAP. ASU 2016-02 is effective for public business entities for annual and interim periods in fiscal years beginning after December 15, 2018. ASU 2016-02 mandates a modified retrospective transition method for all entities. The Company is currently evaluating the impact of this ASU on the Company’s consolidated financial statements and related disclosures. Based on the current status of this assessment, the adoption of this guidance is not expected to have a material impact on the Company’s financial statements. Intangibles – Goodwill and Other In January 2017, the FASB issued ASU 2017-04, “Intangibles-Goodwill and Other: Simplifying the Test for Goodwill Impairment”, which no longer requires an entity to perform a hypothetical purchase price allocation to measure goodwill impairment. Instead, goodwill will be measured using the difference between the carrying amount and the fair value of the reporting unit. The guidance is effective for the interim and annual periods beginning on or after December 15, 2019, with early adoption permitted. The adoption of this guidance is not expected to have a material impact on the Company’s financial statements. Compensation – Retirement Benefits In March 2017, the FASB issued ASU 2017-07, “Compensation – Retirement Benefits: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost”, which requires companies to present the service cost component of the net benefit cost in the same line items in which they report compensation cost. All other components of net periodic benefit cost will be presented outside operating income. The guidance is effective for the interim and annual periods beginning on or after December 15, 2017. We adopted this new standard effective January 1, 2018. The adoption of this guidance is not expected to have a material impact on the Company’s financial statements. Derivatives and Hedging In August 2017, the FASB issued accounting guidance to improve and simplify existing guidance to allow companies to better reflect their risk management activities in the financial statements. The guidance expands the ability to hedge nonfinancial and financial risk components, eliminates the requirement to separately measure and recognize hedge ineffectiveness and eases requirements of an entity’s assessment of hedge effectiveness. The adoption of this guidance is not expected to have a material impact on the Company’s financial statements. Adoption of ASU 2016-09, Stock Compensation- Improvements to Employee Share-Based Payment Accounting On January 1, 2017, the Company adopted the provisions of ASU 2016-09, “Stock Compensation – Improvements to Employee Share-Based Payment Accounting”, an amendment to account standards codification (“ASC”) 718, which simplifies several aspects of accounting for share-based payments, including accounting for income taxes, forfeitures, statutory withhold rates as well as presentation on the statement of cash flows. The Company has elected to adopt the standard on a prospective basis. As a result of this adoption, the Company recognizes excess tax benefits in the current account period. The cash flow benefit of the excess tax benefit is included as an operating activity in the Consolidated Statement of Cash Flows for the period ended December 31, 2017. Additionally, taxes paid for shares withheld for tax-withholding purposes are reported as financing activities in the Condensed Consolidated Statements of Cash Flows. Previously, this activity was included in operating activities. Prior year Condensed Consolidated Statement of Cash Flows has not been restated. In accordance with the standard, the Company will continue to account for forfeitures using an estimated forfeiture rate.

Restructuring and Other Items30

Restructuring and Other Items, net (Tables)	12 Months Ended
	Dec. 31, 2017
Restructuring and Other Items, net [Abstract]
Schedule of restructuring charges	The following table outlines the amount of restructuring charges recorded within the Consolidated Statements of Income, and the segments they relate to: Restructuring and Other Items, net Year Ended December 31, 2017 2017 2016 2015 (millions of dollars) Impairment of assets Specialty Minerals $ 5.3 $ - $ - Performance Materials - - - Energy Services - 18.5 33.0 Corporate - - 1.2 Total impairment of assets charges $ 5.3 $ 18.5 $ 34.2 Severance and other employee costs Specialty Minerals $ 5.0 $ - $ - Performance Materials - - - Refractories - - 2.0 Energy Services 1.7 12.7 9.0 Corporate 4.1 - - Total severance and other employee costs $ 10.8 $ 12.7 $ 11.0 Other Refractories $ - $ (2.0 ) $ - Energy Services (1.1 ) (0.9 ) - Total restructuring and other items, net $ 15.0 $ 28.3 $ 45.2
Reconciliation of restructuring liability	The following table is a reconciliation of our restructuring liability balance: (millions of dollars) Restructuring liability, December 31, 2016 $ 3.6 Additional provisions 10.8 Cash payments (6.3 ) Restructuring liability, December 31, 2017 $ 8.1

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Stock-Based Compensation [Abstract]
Weighted average assumptions used to determine fair value for stock awards	The fair value for stock awards was estimated at the date of grant using the Black-Scholes option valuation model with the following weighted average assumptions for the years ended December 31, 2017, 2016 and 2015: 2017 2016 2015 Expected life (in years) 6.4 6.5 6.4 Interest rate 2.04 % 1.72 % 1.52 % Volatility 36.61 % 36.75 % 36.86 % Expected dividend yield 0.26 % 0.54 % 0.33 %
Summary of stock option activity	The following table summarizes stock option activity for the year ended December 31, 2017: Awards Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Life (Years) Aggregate Intrinsic Value (Millions) Awards outstanding at December 31, 2016 1,198,725 $ 41.66 Granted 187,533 77.99 Exercised (353,636 ) 41.56 Canceled (35,783 ) 50.47 Awards outstanding at December 31, 2017 996,839 $ 48.21 6.32 $ 22.2 Awards exercisable at December 31, 2017 596,446 $ 41.01 4.94 $ 16.6
Non-vested stock option activity	Non-vested stock option activity for the year ended is as follows: Awards Weighted Average Grant date Fair Value Per Share Nonvested awards outstanding at December 31, 2016 431,412 $ 45.61 Granted 187,533 77.99 Vested (183,679 ) 48.78 Canceled (34,873 ) 50.08 Nonvested awards outstanding at December 31, 2017 400,393 $ 58.94
Summary of restricted stock activity	The following table summarizes the restricted stock activity for the Plan: Awards Weighted Average Grant Date Fair Value Per Share Unvested balance at December 31, 2016 227,213 $ 49.57 Granted 69,539 78.00 Vested (61,274 ) 52.51 Canceled (55,368 ) 52.74 Unvested balance at December 31, 2017 180,110 $ 58.57

Earnings Per Share (EPS) (Table

Earnings Per Share (EPS) (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share (EPS) [Abstract]
Computation of basic and diluted earnings per share	Year Ended December 31, 2017 2016 2015 (in millions, except per share data) Net income attributable to MTI $ 195.1 $ 133.4 $ 107.9 Weighted average shares outstanding 35.2 34.9 34.7 Dilutive effect of stock options and stock units 0.4 0.3 0.3 Weighted average shares outstanding, adjusted 35.6 35.2 35.0 Basic earnings per share attributable to MTI $ 5.54 $ 3.82 $ 3.11 Diluted earnings per share attributable to MTI $ 5.48 $ 3.79 $ 3.08

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Income from operations before provision for taxes by domestic and foreign source	Income from operations before provision for taxes by domestic and foreign source is as follows: 2017 2016 2015 (millions of dollars) Income from continuing operations before income taxes and income from affiliates and joint ventures: Domestic $ 96.7 $ 72.9 $ 32.6 Foreign 94.2 97.4 100.0 $ 190.9 $ 170.3 $ 132.6
Provision (benefit) for taxes on income	The provision (benefit) for taxes on income consists of the following: 2017 2016 2015 (millions of dollars) Domestic Taxes currently payable Federal $ 46.0 $ 18.7 $ 1.4 State and local 2.4 4.4 1.2 Deferred income taxes (78.1 ) (8.8 ) (3.2 ) Domestic tax provision (benefit) (29.7 ) 14.3 (0.6 ) Foreign Taxes currently payable 21.1 23.2 22.7 Deferred income taxes 2.0 (2.2 ) 0.7 Foreign tax provision 23.1 21.0 23.4 Total tax provision (benefit) $ (6.6 ) $ 35.3 $ 22.8
Reconciliation of statutory federal tax rate to effective federal tax rate	The major elements contributing to the difference between the U.S. federal statutory tax rate and the consolidated effective tax rate are as follows: 2017 2016 2015 U.S. statutory rate 35.0 % 35.0 % 35.0 % Depletion (6.7 )% (6.6 )% (8.4 )% Difference between tax provided on foreign earnings and the U.S. statutory rate (3.8 )% (6.4 )% (8.3 )% State and local taxes, net of federal tax benefit 1.1 % 1.1 % 0.3 % Tax credits and foreign dividends 0.3 % 0.6 % (0.5 )% Change in valuation allowance (1.9 )% (1.1 )% (0.9 )% Impact of uncertain tax positions 0.4 % 0.4 % (0.1 )% Impact of officer's non-deductible compensation 0.8 % 0.1 % 2.9 % Manufacturing deduction (1.6 )% (2.0 )% (2.0 )% Impact of US Tax Reform (24.8 )% 0.0 % 0.0 % Other (2.3 )% (0.4 )% (0.8 )% Consolidated effective tax rate (3.5 )% 20.7 % 17.2 %
Deferred tax assets and liabilities	The Company believes that its accrued liabilities are sufficient to cover its U.S. and foreign tax contingencies. The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities are presented below: 2017 2016 (millions of dollars) Deferred tax assets attributable to: Accrued liabilities $ 28.6 $ 49.7 Net operating loss carry forwards 33.2 34.6 Pension and post-retirement benefits costs 40.4 55.4 Other 22.0 35.0 Valuation allowance (21.4 ) (24.8 ) Total deferred tax assets 102.8 149.9 Deferred tax liabilities attributable to: Plant and equipment, principally due to differences in depreciation 161.6 251.3 Intangible assets 63.4 96.3 Other 11.6 14.0 Total deferred tax liabilities 236.6 361.6 Net deferred tax asset (liability) $ (133.8 ) $ (211.7 ) Net deferred tax assets and net deferred tax liabilities are as follows: 2017 2016 (millions of dollars) Net deferred tax asset, long-term $ 25.6 $ 27.1 Net deferred tax liability, long-term 159.4 238.8 Net deferred tax asset (liability), long-term $ (133.8 ) $ (211.7 )
Activity related to unrecognized tax benefits	The following table summarizes the activity related to our unrecognized tax benefits: 2017 2016 (millions of dollars) Balance at beginning of the year $ 13.7 $ 4.0 Increases related to current year tax positions 1.2 8.8 Increases related to new judgements 1.2 0.9 Decreases related to audit settlements and statue expirations (1.4 ) - Balance at the end of the year $ 14.7 $ 13.7

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2017
Inventories [Abstract]
Inventories by major category	The following is a summary of inventories by major category: 2017 2016 (millions of dollars) Raw materials $ 82.5 $ 70.6 Work-in-process 7.9 5.4 Finished goods 92.3 80.5 Packaging and supplies 36.6 30.4 Total inventories $ 219.3 $ 186.9

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Major categories of property, plant and equipment and accumulated depreciation and depletion	The major categories of property, plant and equipment and accumulated depreciation and depletion are presented below: December 31, 2017 2016 (millions of dollars) Mineral rights and reserves $ 545.9 $ 547.8 Land 44.5 42.7 Buildings 199.6 195.6 Machinery and equipment 1,247.5 1,193.6 Furniture and fixtures and other 132.3 123.3 Construction in progress 49.8 38.4 2,219.6 2,141.4 Less: accumulated depreciation and depletion (1,158.3 ) (1,089.6 ) Property, plant and equipment, net $ 1,061.3 $ 1,051.8

Goodwill and Other Intangible36

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Other Intangible Assets [Abstract]
Carrying amount of goodwill by reportable segment	The balance of goodwill by segment and the activity occurring in the past two fiscal years is as follows: Specialty Minerals Refractories Performance Materials Consolidated (millions of dollars) Balance at December 31, 2015 $ 13.3 $ 47.0 $ 720.9 $ 781.2 Change in goodwill relating to: Foreign exchange translation (1.2 ) (1.3 ) - (2.5 ) Total Changes $ (1.2 ) $ (1.3 ) $ - $ (2.5 ) Balance at December 31, 2016 $ 12.1 $ 45.7 $ 720.9 $ 778.7 Change in goodwill relating to: Foreign exchange translation 0.6 - 0.6 Total Changes 0.6 - - 0.6 Balance at December 31, 2017 $ 12.7 $ 45.7 $ 720.9 $ 779.3
Acquired intangible assets subject to amortization	Acquired intangible assets subject to amortization as of December 31, 2017 and December 31, 2016 December 31, 2017 December 31, 2016 Weighted Average Useful Life (Years) Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization (millions of dollars) Tradenames 34 $ 199.8 $ 20.7 $ 199.8 $ 15.3 Technology 12 18.8 4.8 18.8 3.6 Patents and trademarks 17 6.4 5.3 6.4 4.8 Customer relationships 30 4.5 2.2 4.5 1.4 28 $ 229.5 $ 33.0 $ 229.5 $ 25.1

Fair Value of Financial Instr37

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value of Financial Instruments [Abstract]
Fair value of financial assets and liabilities on a recurring basis	The following table sets forth by level within the fair value hierarchy the Company's financial assets and liabilities accounted for at fair value on a recurring basis at the end of each of the past two years. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company's assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. Fair Value Measurements Using Description Asset / (Liability) Balance at 12/31/17 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (millions of dollars) Deferred compensation plan assets $ 12.9 $ - $ 12.9 $ - Supplementary pension plan assets 11.6 - 11.6 - Interest rate swap 2.9 - 2.9 - Fair Value Measurements Using Description Asset / (Liability) Balance at 12/31/17 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (milliions of dollars) Money market funds $ 0.7 $ 0.7 $ - $ -

Long-Term Debt and Commitments

Long-Term Debt and Commitments (Tables)	12 Months Ended
	Dec. 31, 2017
Long-Term Debt and Commitments [Abstract]
Summary of long term debt	The following is a summary of long term debt: December 31, 2017 2016 (millions of dollars) Term Loan Facility- Variable Tranche due February 14, 2024, net of unamortized discount and deferred financing costs of $ 22.7 million and $ 25.8 million $ 655.3 $ 762.3 Term Loan Facility- Fixed Tranche due May 9, 2021, net of unamortized discount and deferred financing costs of $0.5 million and $0.6 million $ 299.5 $ 299.4 Japan Loan Facilities 5.6 5.8 China Loan Facilities 3.2 9.2 Total $ 963.6 $ 1,076.7 Less: Current maturities 3.8 6.8 Long-term debt $ 959.8 $ 1,069.9

Benefit Plans (Tables)

Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Benefit Plans [Abstract]
Obligations and funded status of pension and other postretirement benefit plans	The following table set forth Company's pension obligation and funded status at December 31: Pension Benefits Post-Retirement Benefits 2017 2016 2017 2016 (millions of dollars) Change in benefit obligations: Beginning projected benefit obligation $ 427.9 $ 416.6 $ 9.3 $ 9.3 Service cost 7.9 8.2 0.3 0.3 Interest cost 12.6 13.0 0.3 0.3 Actuarial (gain)/loss 31.5 21.2 (3.0 ) (0.6 ) Benefits paid (20.4 ) (18.3 ) (0.1 ) - Settlements - (0.9 ) Foreign exchange impact 9.6 (11.4 ) 0.1 - Other 0.4 (0.5 ) - Ending projected benefit obligation 469.5 427.9 6.9 9.3 Change in plan assets: Beginning fair value 289.3 282.5 - - Actual return on plan assets 33.8 22.9 - - Employer contributions 10.7 10.5 0.1 - Plan participants' contributions 0.4 0.4 - - Benefits paid (20.4 ) (18.3 ) (0.1 ) - Settlements (0.8 ) (0.5 ) - - Foreign exchange impact 7.2 (8.2 ) - - Ending fair value 320.2 289.3 - - Funded status of the plan $ (149.3 ) $ (138.6 ) $ (6.9 ) $ (9.3 )
Amounts recognized in the consolidated balance sheet	Amounts recognized in the consolidated balance sheet consist of: Pension Benefits Post-Retirement Benefits 2017 2016 2017 2016 (millions of dollars) Current liability $ (0.8 ) $ (0.8 ) $ (0.5 ) $ (0.6 ) Non-current liability (148.5 ) (137.8 ) (6.4 ) (8.7 ) Recognized liability $ (149.3 ) $ (138.6 ) $ (6.9 ) $ (9.3 )
Amounts recognized in accumulated other comprehensive income	Amounts recognized in accumulated other comprehensive income, net of related tax effects, consist of: Pension Benefits Post-Retirement Benefits 2017 2016 2017 2016 (millions of dollars) Net actuarial (gain) loss $ 91.4 $ 82.1 $ (4.1 ) $ (1.7 ) Prior service cost (0.1 ) (0.1 ) (0.7 ) (2.4 ) Amount recognized end of year $ 91.3 $ 82.0 $ (4.8 ) $ (4.1 )
Change in plan assets and benefit obligations recognized in other comprehensive income	Changes in the Plan assets and benefit obligations recognized in other comprehensive income: Pension Benefits Post-Retirement Benefits 2017 2016 2017 2016 (millions of dollars) Current year actuarial gain (loss) $ (15.8 ) $ (8.7 ) $ 2.6 $ 0.3 Amortization of actuarial (gain) loss 7.2 6.8 (0.2 ) (0.1 ) Amortization of prior service credit (gain) loss - 0.4 (2.3 ) (1.9 ) Total recognized in other comprehensive income $ (8.6 ) $ (1.5 ) $ 0.1 $ (1.7 )
Components of net periodic benefit cost	The components of net periodic benefit costs are as follows: Pension Benefits Post-Retirement Benefits 2017 2016 2015 2017 2016 2015 (millions of dollars) Service cost $ 7.9 $ 8.2 $ 10.3 $ 0.3 $ 0.3 $ 0.4 Interest cost 12.6 13.0 15.4 0.3 0.3 0.3 Expected return on plan assets (18.7 ) (18.6 ) (19.7 ) - - - Amortization of prior service cost - 0.6 0.8 (3.1 ) (3.1 ) (3.1 ) Recognized net actuarial (gain) loss 10.8 10.7 12.1 (0.3 ) (0.2 ) (0.1 ) Settlement/curtailment loss - 0.3 - - - - Net periodic benefit cost $ 12.6 $ 14.2 $ 18.9 $ (2.8 ) $ (2.7 ) $ (2.5 )
Estimated amortization of amounts in other accumulated comprehensive income to be recognized in next fiscal year	The 2018 estimated amortization of amounts in other accumulated comprehensive income are as follows: Pension Benefits Post-Retirement Benefits (millions of dollars) Amortization of prior service credit (gain) loss $ - $ (0.9 ) Amortization of net (gain) loss 11.5 (0.6 ) Total cost to be recognized $ 11.5 $ (1.5 )
Weighted average assumptions used to determine net periodic benefit cost and benefit obligation	The weighted average assumptions used to determine net periodic benefit cost in the accounting for the pension benefit plans and other benefit plans for the years ended December 31, 2017, 2016 and 2015 are as follows: 2017 2016 2015 Discount rate 3.56 % 3.88 % 3.71 % Expected return on plan assets 6.61 % 6.89 % 6.89 % Rate of compensation increase 3.01 % 3.03 % 3.04 % The weighted average assumptions used to determine benefit obligations for the pension benefit plans and other benefit plans at December 31, 2017, 2016 and 2015 are as follows: 2017 2016 2015 Discount rate 3.16 % 3.60 % 3.89 % Rate of compensation increase 3.01 % 2.96 % 3.04 %
Weighted average asset allocation percentages	The Company's pension plan weighted average asset allocation percentages at December 31, 2017 and 2016 by asset category are as follows: Asset Category 2017 2016 Equity securities 56.0 % 60.2 % Fixed income securities 36.2 % 32.7 % Real estate 0.8 % 0.7 % Other 7.0 % 6.4 % Total 100.0 % 100.0 %
Fair value of plan assets by asset category	The Company's pension plan fair values at December 31, 2017 and 2016 by asset category are as follows: Asset Category 2017 2016 (millions of dollars) Equity securities $ 179.2 $ 174.1 Fixed income securities 116.0 94.7 Real estate 2.4 1.9 Other 22.6 18.6 Total $ 320.2 $ 289.3
Fair value of plan assets by geographic location	The following table presents domestic and foreign pension plan assets information at December 31, 2017, 2016 and 2015 (the measurement date of pension plan assets): U.S. Plans International Plans 2017 2016 2015 2017 2016 2015 (millions of dollars) Fair value of plan assets $ 241.9 $ 221.9 $ 213.0 $ 78.3 $ 67.4 $ 69.5
Defined benefit pension plan assets measured at fair value	The following table summarizes our defined benefit pension plan assets measured at fair value as of December 31, 2017: Pension Assets Fair Value as of December 31, 2017 Quoted Prices In Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Total (Level 1) (Level 2) (Level 3) (millions of dollars) Equity securities US equities $ 156.1 $ - $ - $ 156.1 Non-US equities 23.1 - - 23.1 Fixed income securities Corporate debt instruments 82.0 34.0 - 116.0 Real estate and other Real estate - - 2.4 2.4 Other 0.2 - 22.4 22.6 Total assets $ 261.4 $ 34.0 $ 24.8 $ 320.2 The following table summarizes our defined benefit pension plan assets measured at fair value as of December 31, 2016: Pension Assets Fair Value as of December 31, 2016 Quoted Prices In Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Total (Level 1) (Level 2) (Level 3) (millions of dollars) Equity securities US equities $ 155.0 $ 0.2 $ - $ 155.2 Non-US equities 18.9 - - 18.9 Fixed income securities Corporate debt instruments 63.4 31.3 - 94.7 Real estate and other Real estate - - 1.9 1.9 Other - 0.2 18.4 18.6 Total assets $ 237.3 $ 31.7 $ 20.3 $ 289.3
Reconciliation of changes in fair value measurement of plan assets using significant unobservable inputs (Level 3)	The following is a reconciliation of changes in fair value measurement of plan assets using significant unobservable inputs (Level 3): (millions of dollars) Beginning balance at December 31, 2015 $ 17.9 Purchases, sales, settlements - Actual return on plan assets still held at reporting date 3.0 Foreign exchange impact (0.6 ) Ending balance at December 31, 2016 $ 20.3 Purchases, sales, settlements - Actual return on plan assets still held at reporting date 3.9 Foreign exchange impact 0.5 Ending balance at December 31, 2017 $ 24.7
Estimated future benefit payments	The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid: Pension Benefits Other Benefits (millions of dollars) 2018 $ 22.9 $ 0.5 2019 $ 24.3 $ 0.5 2020 $ 25.5 $ 0.5 2021 $ 25.4 $ 0.5 2022 $ 26.2 $ 0.5 2023-2026 $ 131.6 $ 2.7

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity [Abstract]
Stock option and restricted stock activity	The following table summarizes stock option and restricted stock activity for the Plans: Stock Options Restricted Shares Shares Available for Grant Shares Weighted Average Exercise Price Per Share ($) Shares Weighted Average Exercise Price Per Share ($) Balance January 1, 2015 996,127 951,079 $ 37.46 175,488 $ 50.56 Authorized 880,000 - - - - Granted (455,275 ) 238,773 60.40 216,502 60.32 Exercised/vested - (74,839 ) 33.12 (59,801 ) 47.51 Canceled 71,113 (23,169 ) 60.22 (47,944 ) 51.43 Balance December 31, 2015 1,491,965 1,091,844 42.29 284,245 58.63 Granted (538,787 ) 383,622 38.59 155,165 38.37 Exercised/vested - (150,944 ) 36.66 (88,746 ) 57.38 Canceled 249,248 (125,797 ) 43.78 (123,451 ) 50.72 Balance December 31, 2016 1,202,426 1,198,725 41.66 227,213 49.57 Granted (257,072 ) 187,533 77.99 69,539 78.00 Exercised/vested - (353,636 ) 41.56 (61,274 ) 52.51 Canceled 91,151 (35,783 ) 50.47 (55,368 ) 52.74 Balance December 31, 2017 1,036,505 996,839 48.21 180,110 58.57

Accumulated Other Comprehensi41

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated other comprehensive income (loss), net of related tax, attributable to MTI	Accumulated other comprehensive income (loss) at December 31 comprised of the following components: 2017 2016 (millions of dollars) Cumulative foreign currency translation $ (104.1 ) $ (147.3 ) Unrecognized pension costs (net of tax benefit of $30.7 in 2017 and $39.4 in 2016) (86.5 ) (78.0 ) Unrealized gain (loss) on cash flow hedges (net of tax expense of $0.7 in 2017 and $1.8 in 2016) 4.5 4.2 $ (186.1 ) $ (221.1 )
Changes in other comprehensive income (loss) by component	The following table summarizes the changes in other comprehensive income (loss) by component: Year Ended December 31, 2017 2016 2015 Pre-Tax Amount Tax (Expense) Benefit Net-of- Tax Amount Pre-Tax Amount Tax (Expense) Benefit Net-of- Tax Amount Pre-Tax Amount Tax (Expense) Benefit Net-of- Tax Amount (millions of dollars) Foreign currency translation adjustment $ 44.7 $ - $ 44.7 $ (40.2 ) $ - $ (40.2 ) $ (76.6 ) $ - $ (76.6 ) Pension plans: Net actuarial gains (losses) and prior service costs arising during the period (17.6 ) 4.4 (13.2 ) (12.5 ) 4.1 (8.4 ) 0.5 0.5 1.0 Amortization of net actuarial (gains) losses and prior service costs 7.6 (2.9 ) 4.7 8.0 (2.8 ) 5.2 9.6 (3.3 ) 6.3 Unrealized gains (losses) on cash flow hedges 0.2 0.1 0.3 2.4 (0.8 ) 1.6 - - - Total other comprehensive income (loss) $ 34.9 $ 1.6 $ 36.5 $ (42.3 ) $ 0.5 $ (41.8 ) $ (66.5 ) $ (2.8 ) $ (69.3 )

Accounting for Asset Retireme42

Accounting for Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting for Asset Retirement Obligations [Abstract]
Reconciliation of asset retirement obligations	The following is a reconciliation of asset retirement obligations as of December 31, 2017 and 2016: 2017 2016 (millions of dollars) Asset retirement liability, beginning of period $ 21.5 $ 21.4 Accretion expense 3.3 2.5 Payments (3.2 ) (1.6 ) Foreign currency translation 0.5 (0.8 ) Asset retirement liability, end of period $ 22.1 $ 21.5

Segment and Related Informati43

Segment and Related Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment and Related Information [Abstract]
Segment information	Segment information for the years ended December 31, 2017, 2016 and 2015 was as follows: 2017 2016 2015 (millions of dollars) Net Sales Specialty Minerals $ 584.8 $ 591.5 $ 624.6 Performance Materials 734.8 686.1 694.9 Refractories 279.4 274.5 295.9 Energy Services 76.7 85.9 182.2 Total 1,675.7 1,638.0 1,797.6 Income from Operations Specialty Minerals 88.9 102.7 100.8 Performance Materials 119.7 121.1 118.4 Refractories 39.8 37.0 27.8 Energy Services 6.1 (25.9 ) (27.9 ) Total 254.5 234.9 219.1 Depreciation, Depletion and Amortization Specialty Minerals 35.5 34.9 34.0 Performance Materials 40.5 38.9 39.4 Refractories 6.8 6.9 7.5 Energy Services 8.2 11.2 17.4 Total 91.0 91.9 98.3 Segment Assets Specialty Minerals 519.4 491.7 505.3 Performance Materials 1,989.6 1,942.1 1,965.4 Refractories 307.4 283.4 292.7 Energy Services 110.6 104.7 154.7 Total 2,927.0 2,821.9 2,918.1 Capital Expenditures Specialty Minerals 32.6 40.4 51.9 Performance Materials 33.1 12.8 11.1 Refractories 5.9 5.9 11.1 Energy Services 4.5 1.4 11.1 Total 76.1 60.5 85.2
Reconciliation of operating income before income taxes, assets, and capital expenditures from segments to consolidated	A reconciliation of the totals reported for the operating segments to the applicable line items in the consolidated financial statements is as follows: 2017 2016 2015 (millions of dollars) Income from Operations before Provision (Benefit) for Taxes on Income Income from operations for reportable segments $ 254.5 $ 234.9 $ 219.1 Acquisition related transaction and integration costs (3.4 ) (8.0 ) (11.8 ) Unallocated corporate expenses (8.4 ) (6.0 ) (7.0 ) Consolidated income from operations 242.7 220.9 200.3 Non-operating deductions, net (51.8 ) (50.6 ) (67.7 ) Income from continuing operations before provision (benefit) for taxes on income 190.9 170.3 132.6 Total Assets Total segment assets 2,927.0 2,821.9 2,918.1 Corporate assets 43.4 41.5 61.9 Consolidated total assets 2,970.4 2,863.4 2,980.0 Capital Expenditures Total segment capital expenditures 76.1 60.5 85.2 Corporate capital expenditures 0.6 1.9 0.8 Consolidated capital expenditures 76.7 62.4 86.0
Financial information related to operations by geographic area	Financial information relating to the Company's operations by geographic area was as follows: 2017 2016 2015 (millions of dollars) Net Sales United States $ 939.3 $ 936.2 $ 1,049.6 Canada/Latin America 81.6 82.6 86.3 Europe/Africa 349.0 338.8 382.1 Asia 305.8 280.4 279.6 Total International 736.4 701.8 748.0 Consolidated net sales 1,675.7 1,638.0 1,797.6 Long-Lived Assets United States $ 1,774.4 $ 1,794.5 $ 1,829.3 Canada/Latin America 14.8 14.8 13.0 Europe/Africa 115.9 98.2 117.6 Asia 132.0 127.3 138.3 Total International 262.7 240.3 268.9 Consolidated long-lived assets 2,037.1 2,034.8 2,098.2
Sales by product category	The Company's sales by product category are as follows: 2017 2016 2015 (millions of dollars) Paper PCC $ 377.7 $ 387.9 $ 423.3 Specialty PCC 66.0 64.3 64.8 Talc 53.8 55.7 55.9 Ground Calcium Carbonate 87.3 83.6 80.6 Metalcasting 294.3 258.0 266.4 Household, Personal Care & Specialty Products 169.6 171.2 172.7 Basic Minerals 125.0 103.9 106.0 Environmental Products 67.7 78.9 69.8 Building Materials 78.2 74.1 80.0 Refractory Products 226.9 219.0 230.7 Metallurgical Products 52.5 55.5 65.2 Energy Services 76.7 85.9 182.2 Total $ 1,675.7 $ 1,638.0 $ 1,797.6

Quarterly Financial Data (una44

Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Data (unaudited) [Abstract]
Quarterly Financial Data	2017 quarters First Second Third Fourth (millions of dollars, except per share amounts) Net sales by segment Specialty Minerals segment $ 146.2 $ 147.0 $ 147.7 $ 143.9 Performance Materials segment 169.9 180.3 188.8 $ 195.8 Refractories segment 70.2 68.9 69.0 $ 71.3 Energy Services segment 18.7 17.9 19.0 $ 21.1 Net sales 405.0 414.1 424.5 432.1 Gross profit 113.7 119.7 119.3 114.5 Income from operations 61.7 68.5 66.8 45.7 Consolidated net income 35.6 43.8 42.8 76.7 Net income attributable to Minerals Technologies Inc. (MTI) 34.6 43.0 41.7 75.8 Basic earnings per share attributable to MTI shareholders $ 0.99 $ 1.23 $ 1.18 $ 2.14 Diluted earnings per share attributable to MTI shareholders $ 0.97 $ 1.21 $ 1.17 $ 2.12 Market price range per share of common stock: High $ 83.70 $ 80.20 $ 75.60 $ 73.55 Low $ 72.20 $ 70.50 $ 62.95 $ 66.40 Close $ 76.60 $ 73.20 $ 70.65 $ 68.85 Dividends paid per common share $ 0.05 $ 0.05 $ 0.05 $ 0.05 2016 quarters First Second Third Fourth (millions of dollars, except per share amounts) Net sales by segment Specialty Minerals segment $ 155.6 $ 150.6 $ 147.3 $ 138.0 Performance Materials segment 159.6 182.5 169.0 175.0 Refractories segment 69.2 73.9 63.4 68.0 Energy Services segment 25.8 20.0 19.8 20.3 Net sales 410.2 427.0 399.5 401.3 Gross profit 112.7 121.1 115.2 111.4 Income from operations 57.6 39.5 67.3 56.5 Consolidated net income 34.8 22.3 42.5 37.5 Net income attributable to MTI 33.9 21.2 41.6 36.7 Basic earnings per share attributable to MTI shareholders $ 0.97 $ 0.61 $ 1.19 $ 1.05 Diluted earnings per share attributable to MTI shareholders $ 0.97 $ 0.60 $ 1.18 $ 1.04 Market price range per share of common stock: High $ 57.12 $ 61.66 $ 72.51 $ 82.90 Low $ 37.03 $ 52.53 $ 56.00 $ 66.10 Close $ 57.12 $ 57.38 $ 70.69 $ 77.25 Dividends paid per common share $ 0.05 $ 0.05 $ 0.05 $ 0.05

Summary of Significant Accoun45

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash Equivalents and Short-term Investments [Abstract]
Short-term investments	$ 2.7	$ 2
Unrealized holding gains and losses on short-term bank investments	$ 0
Trade Accounts Receivable [Abstract]
Past due threshold for individual collectability review	90 days
Property, Plant and Equipment [Abstract]
Initial term of long term evergreen contracts	10 years
Investment in Joint Ventures [Abstract]
Equity method investment	$ 16.1
Cost method investment	$ 0
Buildings [Member] | Minimum [Member]
Property, Plant and Equipment [Abstract]
Annual rates of depreciation	3.00%
Buildings [Member] | Maximum [Member]
Property, Plant and Equipment [Abstract]
Annual rates of depreciation	6.67%
Machinery and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Abstract]
Annual rates of depreciation	6.67%
Machinery and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Abstract]
Annual rates of depreciation	12.50%
Furniture and Fixtures [Member] | Minimum [Member]
Property, Plant and Equipment [Abstract]
Annual rates of depreciation	8.00%
Furniture and Fixtures [Member] | Maximum [Member]
Property, Plant and Equipment [Abstract]
Annual rates of depreciation	12.50%
Computer Equipment and Software-related Assets [Member] | Minimum [Member]
Property, Plant and Equipment [Abstract]
Annual rates of depreciation	12.50%
Computer Equipment and Software-related Assets [Member] | Maximum [Member]
Property, Plant and Equipment [Abstract]
Annual rates of depreciation	25.00%
PCC Production Facilities [Member]
Property, Plant and Equipment [Abstract]
Estimated useful life	15 years
Machinery and Equipment for Natural Stone Mining and Processing Plants and Chemical Plants [Member]
Property, Plant and Equipment [Abstract]
Estimated useful life	15 years

Restructuring and Other Items46

Restructuring and Other Items, net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Annualized savings from reduction of workforce	$ 6	$ 11.5
Restructuring Charges [Abstract]
Impairment of assets charges	5.3	18.5	$ 34.2
Severance and other employee costs	10.8	12.7	11
Total restructuring and other items, net	15	28.3	45.2
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning of period	3.6
Additional provisions	10.8
Cash payments	(6.3)
Restructuring liability, ending of period	8.1	3.6
Specialty Minerals [Member]
Restructuring Charges [Abstract]
Impairment of assets charges	5.3	0	0
Severance and other employee costs	5	0	0
Performance Materials [Member]
Restructuring Charges [Abstract]
Impairment of assets charges	0	0	0
Severance and other employee costs	0	0	0
Refractories [Member]
Restructuring Cost and Reserve [Line Items]
Gain on previously impaired assets		2.9
Restructuring Charges [Abstract]
Severance and other employee costs	0	0	2
Other	0	(2)	0
Energy Services [Member]
Restructuring Charges [Abstract]
Impairment of assets charges	0	18.5	33
Severance and other employee costs	1.7	12.7	9
Other	(1.1)	(0.9)	0
Corporate [Member]
Restructuring Charges [Abstract]
Impairment of assets charges	0	0	1.2
Severance and other employee costs	$ 4.1	$ 0	$ 0

Stock-Based Compensation, Stock

Stock-Based Compensation, Stock Award and Incentive Plan and Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock available for issuance (in shares)			880,000
Term of stock options granted under Plan	10 years
Vesting period, generally, for stock options granted under the plan	3 years
Share based compensation costs	$ 4,100	$ 3,500	$ 4,000
Tax benefit of share-based compensation	$ 1,100	$ 1,400	$ 1,600
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Forfeiture rate assumed	8.71%	7.38%	7.34%
Weighted average grant date fair value for stock options granted (in dollars per share)	$ 30.28	$ 14.34	$ 22.68
Weighted average grant date fair value for stock options vested (in dollars per share)	$ 18.45	$ 20.94	$ 17.83
Total intrinsic value of stock options exercised	$ 11,700	$ 4,900	$ 2,400
Weighted Average Assumptions [Abstract]
Expected life	6 years 4 months 24 days	6 years 5 months 23 days	6 years 4 months 24 days
Interest rate	2.04%	1.72%	1.52%
Volatility	36.61%	36.75%	36.86%
Expected dividend yield	0.26%	0.54%	0.33%
Stock Options [Roll Forward]
Balance, beginning of year (in shares)	1,198,725
Granted (in shares)	187,533
Exercised (in shares)	(353,636)
Canceled (in shares)	(35,783)
Balance, end of year (in shares)	996,839	1,198,725
Exercisable, end of year (in shares)	596,446
Weighted Average Exercise Price Per Share [Abstract]
Balance, beginning of year (in dollars per share)	$ 41.66
Granted (in dollars per share)	77.99
Exercised (in dollars per share)	41.56
Canceled (in dollars per share)	50.47
Balance, end of year (in dollars per share)	48.21	$ 41.66
Exercisable, end of year (in dollars per share)	$ 41.01
Weighted Average Remaining Contractual Life [Abstract]
Outstanding options, end of year	6 years 3 months 25 days
Exercisable options, end of year	4 years 11 months 8 days
Aggregate Intrinsic Value [Abstract]
Outstanding options, end of year	$ 22,200
Exercisable options, end of year	$ 16,600
Additional Information [Abstract]
Closing stock price on last business day of the period (in dollars per share)	$ 68.85
Weighted average intrinsic value of options exercised (in dollars per share)	$ 32.95	$ 32.34	$ 32.07
Unrecognized stock-based compensation expense	$ 4,500
Weighted average period over which unrecognized stock-based compensation expense is expected to be recognized	3 years
Nonvested Stock Options [Member]
Stock Options [Roll Forward]
Balance, beginning of year (in shares)	431,412
Granted (in shares)	187,533
Vested (in shares)	(183,679)
Canceled (in shares)	(34,873)
Balance, end of year (in shares)	400,393	431,412
Weighted Average Exercise Price Per Share [Abstract]
Balance, beginning of year (in dollars per share)	$ 45.61
Granted (in dollars per share)	77.99
Vested (in dollars per share)	48.78
Canceled (in dollars per share)	50.08
Balance, end of year (in dollars per share)	$ 58.94	$ 45.61
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation costs	$ 5,900	$ 5,800	$ 8,800
Additional Information [Abstract]
Unrecognized stock-based compensation expense	$ 5,100
Weighted average period over which unrecognized stock-based compensation expense is expected to be recognized	3 years

Stock-Based Compensation, Restr

Stock-Based Compensation, Restricted Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation costs	$ 4,100	$ 3,500	$ 4,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense	$ 4,500
Weighted average period over which unrecognized stock-based compensation expense is expected to be recognized	3 years
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense	$ 5,100
Weighted average period over which unrecognized stock-based compensation expense is expected to be recognized	3 years
Share based compensation costs	$ 5,900	5,800	8,800
Reversals of compensation expense related to restricted stock forfeitures	$ 2,400	$ 3,800	$ 1,600
Restricted Stock [Roll Forward]
Balance, beginning of year (in shares)	227,213	284,245	175,488
Granted (in shares)	69,539	155,165	216,502
Vested (in shares)	(61,274)	(88,746)	(59,801)
Canceled (in shares)	(55,368)	(123,451)	(47,944)
Balance, end of year (in shares)	180,110	227,213	284,245
Weighted Average Grant Date Fair Value [Abstract]
Balance, beginning of year (in dollars per share)	$ 49.57	$ 58.63	$ 50.56
Granted (in dollars per share)	78	38.37	60.32
Vested (in dollars per share)	52.51	57.38	47.51
Canceled (in dollars per share)	52.74	50.72	51.43
Balance, end of year (in dollars per share)	$ 58.57	$ 49.57	$ 58.63

Earnings Per Share (EPS) (Detai

Earnings Per Share (EPS) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2016	Oct. 02, 2016	Jul. 03, 2016	Apr. 03, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share (EPS) [Abstract]
Net income attributable to MTI	$ 75.8	$ 41.7	$ 43	$ 34.6	$ 36.7	$ 41.6	$ 21.2	$ 33.9	$ 195.1	$ 133.4	$ 107.9
Weighted average shares outstanding (in shares)									35,200,000	34,900,000	34,700,000
Dilutive effect of stock options and stock units (in shares)									400,000	300,000	300,000
Weighted average shares outstanding, adjusted (in shares)									35,600,000	35,200,000	35,000,000
Basic earnings per share attributable to MTI (in dollars per share)	$ 2.14	$ 1.18	$ 1.23	$ 0.99	$ 1.05	$ 1.19	$ 0.61	$ 0.97	$ 5.54	$ 3.82	$ 3.11
Diluted earnings per share attributable to MTI (in dollars per share)	$ 2.12	$ 1.17	$ 1.21	$ 0.97	$ 1.04	$ 1.18	$ 0.60	$ 0.97	$ 5.48	$ 3.79	$ 3.08
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in the weighted average commons shares outstanding calculation (in shares)									181,003	784	386,766

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Line Items]
Provisional income tax benefit	$ (47.3)
Domestic			$ 96.7	$ 72.9	$ 32.6
Foreign			94.2	97.4	100
Income from operations before provision for taxes and equity in earnings			190.9	170.3	132.6
Domestic [Abstract]
Taxes currently payable, Federal			46	18.7	1.4
Taxes currently payable, State and local			2.4	4.4	1.2
Deferred income taxes			(78.1)	(8.8)	(3.2)
Domestic tax provision (benefit)			(29.7)	14.3	(0.6)
Foreign [Abstract]
Taxes currently payable			21.1	23.2	22.7
Deferred income taxes			2	(2.2)	0.7
Foreign tax provision			23.1	21	23.4
Total tax provision (benefit)			$ (6.6)	$ 35.3	$ 22.8
Reconciliation of U. S. federal statutory tax rate to effective tax rate [Abstract]
U.S. statutory rate			35.00%	35.00%	35.00%
Depletion			(6.70%)	(6.60%)	(8.40%)
Difference between tax provided on foreign earnings and the US statutory rate			(3.80%)	(6.40%)	(8.30%)
State and local taxes, net of federal tax benefit			1.10%	1.10%	0.30%
Tax credits and foreign dividends			0.30%	0.60%	(0.50%)
Change in valuation allowance			(1.90%)	(1.10%)	(0.90%)
Impact of uncertain tax positions			0.40%	0.40%	(0.10%)
Impact of officer's non-deductible compensation			0.80%	0.10%	2.90%
Manufacturing deduction			(1.60%)	(2.00%)	(2.00%)
Impact of US Tax Reform			(24.80%)	(0.00%)	(0.00%)
Other			(2.30%)	(0.40%)	(0.80%)
Consolidated effective tax rate			(3.50%)	20.70%	17.20%
Deferred tax assets attributable to [Abstract]
Accrued liabilities	28.6		$ 28.6	$ 49.7
Net operating loss carry forwards	33.2		33.2	34.6
Pension and post-retirement benefits costs	40.4		40.4	55.4
Other	22		22	35
Valuation allowance	(21.4)		(21.4)	(24.8)
Total deferred tax assets	102.8		102.8	149.9
Deferred tax liabilities attributable to [Abstract]
Plant and equipment, principally due to differences in depreciation	161.6		161.6	251.3
Intangible assets	63.4		63.4	96.3
Other	11.6		11.6	14
Total deferred tax liabilities	236.6		236.6	361.6
Net deferred tax asset (liability)	(133.8)		(133.8)	(211.7)
Current and long-term portion of net deferred tax assets [Abstract]
Net deferred tax asset, long-term	25.6		25.6	27.1
Net deferred tax liability, long-term	159.4		159.4	238.8
Net deferred tax asset (liability), long-term	(133.8)		(133.8)	(211.7)
Operating Loss Carryforwards [Line Items]
Deferred tax assets arising from tax loss carry forwards which will be realized through future operations	33.2		$ 33.2
Expiration period			20 years
Unrecognized tax benefits [Abstract]
Unrecognized tax benefits that would impact effective tax rate	11.9		$ 11.9
Unrecognized tax benefits [Roll forward]
Balance at beginning of the year		$ 14.7	13.7	4
Increases related to current year positions			1.2	8.8
Increases related to new judgments			1.2	0.9
Decreases related to audit settlements and statute expirations			(1.4)	0
Balance at the end of the year	14.7		14.7	13.7	$ 4
Income Tax Penalties and Interest Expense [Abstract]
Unrecognized tax benefits, net reversal of accrued interest and penalties			0.4
Unrecognized tax benefits, accrued interest and penalties	1.7		1.7
Cash paid for income taxes [Abstract]
Net cash Income taxes paid			47.7	$ 30.6	$ 43.8
Undistributed earnings of foreign subsidiaries [Abstract]
Foreign subsidiaries' undistributed earnings	531.2		531.2
Deferred tax liabilities with respect to foreign withholding taxes or state taxes have been recognized	0		0
Finite lived tax loss carry forwards [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax assets arising from tax loss carry forwards which will be realized through future operations	15.5		15.5
Indefinite lived tax loss carry forwards [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax assets arising from tax loss carry forwards which will be realized through future operations	$ 17.7		$ 17.7
Plan [Member]
Reconciliation of U. S. federal statutory tax rate to effective tax rate [Abstract]
U.S. statutory rate		21.00%

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Inventories [Abstract]
Raw materials	$ 82.5	$ 70.6
Work-in-process	7.9	5.4
Finished goods	92.3	80.5
Packaging and supplies	36.6	30.4
Total inventories	$ 219.3	$ 186.9

Property, Plant and Equipment52

Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,219.6	$ 2,141.4
Less: accumulated depreciation and depletion	(1,158.3)	(1,089.6)
Property, plant and equipment, net	1,061.3	1,051.8
Depreciation and depletion expense	75.6	75.4	$ 82.1
Mineral Rights and Reserves [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	545.9	547.8
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	44.5	42.7
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	199.6	195.6
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,247.5	1,193.6
Furniture and Fixtures and Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	132.3	123.3
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 49.8	$ 38.4

Goodwill and Other Intangible53

Goodwill and Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Balance Beginning	$ 778.7	$ 781.2
Change in goodwill relating to [Abstract]
Foreign exchange translation	0.6	(2.5)
Total	0.6	(2.5)
Balance Ending	$ 779.3	778.7
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	28 years
Gross carrying amount	$ 229.5	229.5
Accumulated amortization	33	25.1
Specialty Minerals [Member]
Goodwill [Roll Forward]
Balance Beginning	12.1	13.3
Change in goodwill relating to [Abstract]
Foreign exchange translation	0.6	(1.2)
Total	0.6	(1.2)
Balance Ending	12.7	12.1
Refractories [Member]
Goodwill [Roll Forward]
Balance Beginning	45.7	47
Change in goodwill relating to [Abstract]
Foreign exchange translation	0	(1.3)
Total	0	(1.3)
Balance Ending	45.7	45.7
Performance Materials [Member]
Goodwill [Roll Forward]
Balance Beginning	720.9	720.9
Change in goodwill relating to [Abstract]
Foreign exchange translation	0	0
Total	0	0
Balance Ending	$ 720.9	720.9
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	34 years
Gross carrying amount	$ 199.8	199.8
Accumulated amortization	$ 20.7	15.3
Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	12 years
Gross carrying amount	$ 18.8	18.8
Accumulated amortization	$ 4.8	3.6
Patents and Trademarks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	17 years
Gross carrying amount	$ 6.4	6.4
Accumulated amortization	$ 5.3	4.8
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	30 years
Gross carrying amount	$ 4.5	4.5
Accumulated amortization	$ 2.2	$ 1.4

Goodwill and Other Intangible54

Goodwill and Other Intangible Assets, Acquired Intangible Assets (Details) - Acquired Finite-Lived Intangible Assets [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 8	$ 8.2	$ 7.9
Estimated amortization expense, 2018	7.9
Estimated amortization expense, 2019	7.9
Estimated amortization expense, 2020	7.9
Estimated amortization expense, 2021	7.9
Estimated amortization expense, 2022	7.9
Estimated amortization expense, thereafter	$ 157

Derivative Financial Instrume55

Derivative Financial Instruments and Hedging Activities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)Contract	Dec. 31, 2016USD ($)Contract	Dec. 31, 2015USD ($)	Jul. 03, 2016USD ($)
Derivatives, Fair Value [Line Items]
(Gains) losses in other non-operating income (deductions)	$ 4.5	$ (3.8)	$ 2.3
Foreign Exchange Forward [Member]
Derivatives, Fair Value [Line Items]
Number of contracts | Contract	0	2
(Gains) losses in other non-operating income (deductions)	$ (1.2)	$ 0.6
Cash Flow Hedges [Member] | Foreign Exchange Forward [Member]
Derivatives, Fair Value [Line Items]
Number of contracts | Contract	2
Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Other Non-current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	$ 2.9
Cash Flow Hedges [Member] | Designated [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional amount	$ 200			$ 300

Fair Value of Financial Instr56

Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers in or out of Level 3	$ 0	$ 0
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan assets	12.9
Supplementary pension plan assets	11.6
Interest rate swap	2.9
Money market funds	0.7
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan assets	0
Supplementary pension plan assets	0
Interest rate swap	0
Money market funds	0.7
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan assets	12.9
Supplementary pension plan assets	11.6
Interest rate swap	2.9
Money market funds	0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan assets	0
Supplementary pension plan assets	0
Interest rate swap	0
Money market funds	$ 0

Financial Instruments and Con57

Financial Instruments and Concentrations of Credit Risk (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financial Instruments and Concentrations of Credit Risk [Abstract]
Bad debt expense	$ 3.8	$ 6.2	$ 2.6

Long-Term Debt and Commitment58

Long-Term Debt and Commitments (Details) ¥ in Millions, ¥ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)Loan	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2017CNY (¥)	Dec. 31, 2017JPY (¥)	Feb. 14, 2017USD ($)	Jun. 23, 2015USD ($)	May 09, 2014USD ($)
Debt Instrument [Line Items]
Debt	$ 963.6	$ 1,076.7
Less: Current maturities	3.8	6.8
Long-term debt	959.8	1,069.9
Maximum borrowing capacity	37.1
Repayments of long-term debt	118.9	193.2	$ 191.8
Uncommitted short-term bank credit lines, amount outstanding	6.3
Short-term Borrowings [Abstract]
Short-term borrowings	$ 6.3	$ 6.1
Weighted average interest rate on short-term borrowings	3.90%	3.70%		3.90%	3.90%
Long-term debt maturities [Abstract]
2,018	$ 3.8
2,019	0.6
2,020	0.6
2,021	304
2,022	0
Thereafter	678
Interest costs [Abstract]
Interest costs	45.4	$ 56.5	62.6
Capitalized interest cost	$ 0.2	0.1	$ 0.5
Minimum [Member]
Debt Instrument [Line Items]
Net leverage ratio	3.50
Maximum [Member]
Debt Instrument [Line Items]
Net leverage ratio	5.25
Term Loan Facility, Due February 14, 2024 [Member]
Debt Instrument [Line Items]
Debt	$ 655.3	762.3
Long-term debt, unamortized discount and deferred financing costs	$ 22.7	25.8
Maturity date	Feb. 14, 2024
Term Loan Facility, Due February 14, 2024 [Member] | Floating Rate Tranche [Member]
Debt Instrument [Line Items]
Amortization rate on notes	1.00%
Term Loan Facility, Due May 9, 2021 [Member]
Debt Instrument [Line Items]
Debt	$ 299.5	299.4
Long-term debt, unamortized discount and deferred financing costs	$ 0.5	0.6
Maturity date	May 9, 2021
Maximum borrowing capacity								$ 1,560
Repayments of long-term debt	$ 110
Term Loan Facility First Amendment [Member]
Debt Instrument [Line Items]
Line of credit outstanding							$ 1,378
Term Loan Facility First Amendment [Member] | Floating Rate Tranche [Member]
Debt Instrument [Line Items]
Line of credit outstanding							1,078
Term Loan Facility First Amendment [Member] | Fixed Rate Tranche [Member]
Debt Instrument [Line Items]
Line of credit outstanding							$ 300
Facility variable interest rate	0.25%			0.25%	0.25%
Term Loan Facility Second Amendment [Member] | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Facility variable interest rate	0.75%			0.75%	0.75%
Term Loan Facility Second Amendment [Member] | LIBOR [Member] | Maximum [Member]
Debt Instrument [Line Items]
Facility variable interest rate	2.25%			2.25%	2.25%
Term Loan Facility Second Amendment [Member] | Floating Rate Tranche [Member]
Debt Instrument [Line Items]
Line of credit outstanding						$ 788
Facility variable interest rate	0.25%			0.25%	0.25%
Basis points related to debt	0.75%
Term Loan Facility Second Amendment [Member] | Fixed Rate Tranche [Member]
Debt Instrument [Line Items]
Facility variable interest rate	4.75%			4.75%	4.75%
Japan Loan Facilities [Member]
Debt Instrument [Line Items]
Debt	$ 5.6	5.8
Maximum borrowing capacity	6				¥ 680
China Loan Facilities [Member]
Debt Instrument [Line Items]
Debt	3.2	$ 9.2
Maximum borrowing capacity	$ 1.8			¥ 94.8
Number of committed loan facilities | Loan	4
Combined Loan Facility of China and Japan [Member]
Debt Instrument [Line Items]
Maturity date	Dec. 31, 2021
Debt instrument outstanding	$ 8.8
Repayments of long-term debt	$ 6.9
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maturity date	May 9, 2019
Maximum borrowing capacity								$ 200
Basis points related to debt	0.25%
Debt instrument outstanding	$ 0
Letters of credit outstanding	$ 12.9
Revolving Credit Facility [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Facility variable interest rate	1.75%			1.75%	1.75%
Letter of Credit [Member]
Debt Instrument [Line Items]
Letters of credit outstanding	$ 15

Benefit Plans, Pension Obligati

Benefit Plans, Pension Obligation and Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Benefit Plans [Abstract]
Employee vesting period for defined benefit plans	5 years
Employer Contributions [Abstract]
Maximum percentage of total benefit obligation for international pension plans	25.00%
Change in plan assets [Roll Forward]
Beginning fair value	$ 289.3
Ending fair value	320.2	$ 289.3
Pension Benefits [Member]
Change in benefit obligations [Roll Forward]
Beginning projected benefit obligation	427.9	416.6
Service cost	7.9	8.2	$ 10.3
Interest cost	12.6	13	15.4
Actuarial (gain)/loss	31.5	21.2
Benefits paid	(20.4)	(18.3)
Settlements	0	(0.9)
Foreign exchange impact	9.6	(11.4)
Other	0.4	(0.5)
Ending projected benefit obligation	469.5	427.9	416.6
Change in plan assets [Roll Forward]
Beginning fair value	289.3	282.5
Actual return on plan assets	33.8	22.9
Employer contributions	10.7	10.5
Plan participants' contributions	0.4	0.4
Benefits paid	(20.4)	(18.3)
Settlements	(0.8)	(0.5)
Foreign exchange impact	7.2	(8.2)
Ending fair value	320.2	289.3	282.5
Funded status of the plan	(149.3)	(138.6)
Post-retirement Benefits [Member]
Change in benefit obligations [Roll Forward]
Beginning projected benefit obligation	9.3	9.3
Service cost	0.3	0.3	0.4
Interest cost	0.3	0.3	0.3
Actuarial (gain)/loss	(3)	(0.6)
Benefits paid	(0.1)	0
Settlements	0	0
Foreign exchange impact	0.1	0
Other	0	0
Ending projected benefit obligation	6.9	9.3	9.3
Change in plan assets [Roll Forward]
Beginning fair value	0	0
Actual return on plan assets	0	0
Employer contributions	0.1	0
Plan participants' contributions	0	0
Benefits paid	(0.1)	0
Settlements	0	0
Foreign exchange impact	0	0
Ending fair value	0	0	$ 0
Funded status of the plan	$ (6.9)	$ (9.3)

Benefit Plans, Amounts Recogniz

Benefit Plans, Amounts Recognized in Consolidated Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Amounts recognized in Balance Sheet [Abstract]
Current liability	$ (55.4)	$ (61.3)
Non-current liability	(155)	(147.3)
Pension Benefits [Member]
Amounts recognized in Balance Sheet [Abstract]
Current liability	(0.8)	(0.8)
Non-current liability	(148.5)	(137.8)
Recognized liability	(149.3)	(138.6)
Post-retirement Benefits [Member]
Amounts recognized in Balance Sheet [Abstract]
Current liability	(0.5)	(0.6)
Non-current liability	(6.4)	(8.7)
Recognized liability	$ (6.9)	$ (9.3)

Benefit Plans, Amounts Recogn61

Benefit Plans, Amounts Recognized in Accumulated Other Comprehensive Income, net of Related Tax Effects (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Amounts recognized in accumulated other comprehensive income [Abstract]
Amount recognized end of year	$ 86.5	$ 78
Accumulated benefit obligation	435.4	394.5
Pension Benefits [Member]
Amounts recognized in accumulated other comprehensive income [Abstract]
Net actuarial (gain) loss	91.4	82.1
Prior service cost	(0.1)	(0.1)
Amount recognized end of year	91.3	82
Post-retirement Benefits [Member]
Amounts recognized in accumulated other comprehensive income [Abstract]
Net actuarial (gain) loss	(4.1)	(1.7)
Prior service cost	(0.7)	(2.4)
Amount recognized end of year	$ (4.8)	$ (4.1)

Benefit Plans, Changes in Plan

Benefit Plans, Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Changes in Plan assets and benefit obligations recognized in other comprehensive income [Abstract]
Amortization of prior service credit (gain) loss	$ (4.7)	$ (5.2)	$ (6.3)
Total recognized in other comprehensive income	8.5	3.2	$ (7.3)
Pension Benefits [Member]
Changes in Plan assets and benefit obligations recognized in other comprehensive income [Abstract]
Current year actuarial gain (loss)	(15.8)	(8.7)
Amortization of actuarial (gain) loss	7.2	6.8
Amortization of prior service credit (gain) loss	0	0.4
Total recognized in other comprehensive income	(8.6)	(1.5)
Post-retirement Benefits [Member]
Changes in Plan assets and benefit obligations recognized in other comprehensive income [Abstract]
Current year actuarial gain (loss)	2.6	0.3
Amortization of actuarial (gain) loss	(0.2)	(0.1)
Amortization of prior service credit (gain) loss	(2.3)	(1.9)
Total recognized in other comprehensive income	$ 0.1	$ (1.7)

Benefit Plans, Components of Ne

Benefit Plans, Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost	$ 7.9	$ 8.2	$ 10.3
Interest cost	12.6	13	15.4
Expected return on plan assets	(18.7)	(18.6)	(19.7)
Amortization of prior service cost	0	0.6	0.8
Recognized net actuarial (gain) loss	10.8	10.7	12.1
Settlement/curtailment loss	0	0.3	0
Net periodic benefit cost	12.6	14.2	18.9
Post-retirement Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost	0.3	0.3	0.4
Interest cost	0.3	0.3	0.3
Expected return on plan assets	0	0	0
Amortization of prior service cost	(3.1)	(3.1)	(3.1)
Recognized net actuarial (gain) loss	(0.3)	(0.2)	(0.1)
Settlement/curtailment loss	0	0	0
Net periodic benefit cost	$ (2.8)	$ (2.7)	$ (2.5)

Benefit Plans, Estimated Amorti

Benefit Plans, Estimated Amortization of Amounts in Other Accumulated Comprehensive Income (Details) $ in Millions	Dec. 31, 2017USD ($)
Pension Benefits [Member]
Amounts that will be amortized from Accumulated other comprehensive income (loss) in next fiscal year [Abstract]
Amortization of prior service credit (gain) loss	$ 0
Amortization of net (gain) loss	11.5
Total costs to be recognized	11.5
Post-retirement Benefits [Member]
Amounts that will be amortized from Accumulated other comprehensive income (loss) in next fiscal year [Abstract]
Amortization of prior service credit (gain) loss	(0.9)
Amortization of net (gain) loss	(0.6)
Total costs to be recognized	$ (1.5)

Benefit Plans, Weighted Average

Benefit Plans, Weighted Average Assumptions Used (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Weighted average assumptions used to determine net periodic benefit cost [Abstract]
Discount rate	3.56%	3.88%	3.71%
Expected return on plan assets	6.61%	6.89%	6.89%
Rate of compensation increase	3.01%	3.03%	3.04%
Weighted average assumptions used to determine benefit obligation [Abstract]
Discount rate	3.16%	3.60%	3.89%
Rate of compensation increase	3.01%	2.96%	3.04%
Actual return on pension assets	11.00%	8.00%	1.00%
Maximum health care cost trend rate	5.00%

Benefit Plans, Weighted Avera66

Benefit Plans, Weighted Average Asset Allocation by Asset Category (Details)	Dec. 31, 2017	Dec. 31, 2016
Weighted average asset allocations [Abstract]
Weighted average asset allocation percentages, Total	100.00%	100.00%
Equity Securities [Member]
Weighted average asset allocations [Abstract]
Weighted average asset allocation percentages, Total	56.00%	60.20%
Fixed Income Securities [Member]
Weighted average asset allocations [Abstract]
Weighted average asset allocation percentages, Total	36.20%	32.70%
Real Estate [Member]
Weighted average asset allocations [Abstract]
Weighted average asset allocation percentages, Total	0.80%	0.70%
Other [Member]
Weighted average asset allocations [Abstract]
Weighted average asset allocation percentages, Total	7.00%	6.40%

Benefit Plans, Fair Values by A

Benefit Plans, Fair Values by Asset Category (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Weighted average asset allocations value [Abstract]
Fair value of plan assets	$ 320.2	$ 289.3
Equity Securities [Member]
Weighted average asset allocations value [Abstract]
Fair value of plan assets	179.2	174.1
Fixed Income Securities [Member]
Weighted average asset allocations value [Abstract]
Fair value of plan assets	116	94.7
Real Estate [Member]
Weighted average asset allocations value [Abstract]
Fair value of plan assets	2.4	1.9
Other [Member]
Weighted average asset allocations value [Abstract]
Fair value of plan assets	$ 22.6	$ 18.6

Benefit Plans, Domestic and For

Benefit Plans, Domestic and Foreign Pension Plan Assets and Summary of Defined Benefit Pension Plan Assets Measured at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair value of plan assets [Abstract]
Fair value of plan assets	$ 320.2	$ 289.3
Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	261.4	237.3
Significant Other Observable Inputs (Level 2) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	34	31.7
Significant Unobservable Inputs (Level 3) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	24.8	20.3
Equity Securities [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	179.2	174.1
US Equities [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	156.1	155.2
US Equities [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	156.1	155
US Equities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0.2
US Equities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non-US Equities [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	23.1	18.9
Non-US Equities [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	23.1	18.9
Non-US Equities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non-US Equities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Fixed Income Securities [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	116	94.7
Corporate Debt Instruments [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	116	94.7
Corporate Debt Instruments [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	82	63.4
Corporate Debt Instruments [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	34	31.3
Corporate Debt Instruments [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Real Estate [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	2.4	1.9
Real Estate [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Real Estate [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Real Estate [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	2.4	1.9
Other [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	22.6	18.6
Other [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0.2	0
Other [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0.2
Other [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	22.4	18.4
U.S. Plans [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	241.9	221.9	$ 213
International Plans [Member]
Fair value of plan assets [Abstract]
Fair value of plan assets	$ 78.3	$ 67.4	$ 69.5

Benefit Plans, Reconciliation o

Benefit Plans, Reconciliation of Changes in Fair Value Measurement of Plan Assets (Details) - Significant Unobservable Inputs (Level 3) [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of changes in fair value measurement of plan assets [Roll Forward]
Beginning balance	$ 20.3	$ 17.9
Purchases, sales, settlements	0	0
Actual return on plan assets still held at reporting date	3.9	3
Foreign exchange impact	0.5	(0.6)
Ending balance	$ 24.7	$ 20.3

Benefit Plans, Contributions (D

Benefit Plans, Contributions (Details) $ in Millions	Dec. 31, 2017USD ($)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected company contribution to its benefit plans	$ 15
Post-retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected company contribution to its benefit plans	$ 0.5

Benefit Plans, Estimated Future

Benefit Plans, Estimated Future Benefit Payments (Details) $ in Millions	Dec. 31, 2017USD ($)
Pension Benefits [Member]
Estimated future benefit payments [Abstract]
2,018	$ 22.9
2,019	24.3
2,020	25.5
2,021	25.4
2,022	26.2
2023-2026	131.6
Post-retirement Benefits [Member]
Estimated future benefit payments [Abstract]
2,018	0.5
2,019	0.5
2,020	0.5
2,021	0.5
2,022	0.5
2023-2026	$ 2.7

Benefit Plans, Investment Strat

Benefit Plans, Investment Strategies (Details)	12 Months Ended
	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Average rate of return on assets	9.00%
Equity Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target long-term investment portfolio mix	55.00%
Equity Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target long-term investment portfolio mix	65.00%
Fixed Income Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target long-term investment portfolio mix	30.00%
Fixed Income Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target long-term investment portfolio mix	35.00%
Other Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target long-term investment portfolio mix	0.00%
Other Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target long-term investment portfolio mix	15.00%

Benefit Plans, Savings and Inve

Benefit Plans, Savings and Investment Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Benefit Plans [Abstract]
Company's contributions to employee voluntary savings and investment plan	$ 5.2	$ 5.1	$ 6.3

Leases (Details)

Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Leases [Abstract]
Rent expense	$ 19.3	$ 16.2	$ 19.5
Future minimum rental commitments under non-cancelable operating leases [Abstract]
2,018	18.1
2,019	14.5
2,020	10.7
2,021	7.6
2,022	6.5
Thereafter	24.9
Future minimum rentals to be received under non-cancelable subleases	5.2
Future minimum payments to be received under direct financing leases [Abstract]
2,018	0.4
2,019	0.1
2,020	0
2,021	0
2,022	0
Thereafter	$ 0

Litigation (Details)

Litigation (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)ContractLoadCase	Oct. 24, 2014USD ($)	Dec. 31, 2009
Loss Contingencies [Line Items]
Number of contracts entered | Contract	2
Number of ship loads | Load	60
Default arbitration awards | $	$ 70
Number of cases dismissed	0
Site Contingency [Line Items]
Consent decree paid by US government | $		$ 2.3
AMCOL International Corporation [Member]
Loss Contingencies [Line Items]
Ownership interest	19.00%		20.00%
Silica Cases [Member]
Loss Contingencies [Line Items]
Number of pending cases	3
Cumulative number of cases dismissed	1,493
Number of lawsuits settled	1
Asbestos Cases [Member]
Loss Contingencies [Line Items]
Number of pending cases	20
Cumulative number of cases dismissed	53
Number of new cases filed	7
Number of previously reported cases	1
Number of cases dismissed	4
Number of lawsuits settled	0
Number of cases claim liability	13
Number of allege liability	6
Number of cases with no alleged exposure	0
Administrative Consent Order for Contamination Associated with Historic Use of PCBs [Member]
Site Contingency [Line Items]
Location of plant	Canaan, Connecticut
Estimated accrued remediation cost | $	$ 0.4
Administrative Consent Order for Installation of Groundwater Contamination System [Member]
Site Contingency [Line Items]
Location of plant	Adams, Massachusetts plant
Estimated accrued remediation cost | $	$ 0.4
Estimated cost of wastewater treatment upgrades, lower range | $	6
Estimated cost of wastewater treatment upgrades, upper range | $	$ 8

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2016	Oct. 02, 2016	Jul. 03, 2016	Apr. 03, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 31, 2018
Capital Stock [Abstract]
Common stock, shares authorized (in shares)	100,000,000				100,000,000				100,000,000	100,000,000
Common stock, par value (in dollars per share)	$ 0.10				$ 0.10				$ 0.10	$ 0.10
Common stock, shares outstanding (in shares)	35,374,345				34,969,987				35,374,345	34,969,987
Preferred stock, shares authorized (in shares)	1,000,000				1,000,000				1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0				0				0	0
Preferred stock, shares outstanding (in shares)	0				0				0	0
Cash Dividends [Abstract]
Cash dividends paid									$ 7
Cash dividends paid (in dollars per share)	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.20
Stock Award and Incentive Plan [Abstract]
Term of stock options granted under Plan									10 years
Vesting period, generally, for stock options granted under the plan									3 years
Shares Available for Grant [Roll Forward]
Balance, beginning of year (in shares)				1,202,426				1,491,965	1,202,426	1,491,965	996,127
Authorized (in shares)											880,000
Granted (in shares)									(257,072)	(538,787)	(455,275)
Exercised/vested (in shares)									0	0	0
Canceled (in shares)									91,151	249,248	71,113
Balance, end of year (in shares)	1,036,505				1,202,426				1,036,505	1,202,426	1,491,965
Subsequent Event [Member] | Dividend Declared 2018 Q1 [Member]
Cash Dividends [Abstract]
Cash dividend declared												$ 1.7
Cash dividend declared (in dollars per share)												$ 0.05
Stock Options [Member]
Stock Options [Roll Forward]
Balance, beginning of year (in shares)				1,198,725				1,091,844	1,198,725	1,091,844	951,079
Granted (in shares)									187,533	383,622	238,773
Exercised/vested (in shares)									(353,636)	(150,944)	(74,839)
Canceled (in shares)									(35,783)	(125,797)	(23,169)
Balance, end of year (in shares)	996,839				1,198,725				996,839	1,198,725	1,091,844
Weighted Average Exercise Price Per Share [Abstract]
Balance, beginning of year (in dollars per share)				$ 41.66				$ 42.29	$ 41.66	$ 42.29	$ 37.46
Granted (in dollars per share)									77.99	38.59	60.40
Exercised/vested (in dollars per share)									41.56	36.66	33.12
Canceled (in dollars per share)									50.47	43.78	60.22
Balance, end of year (in dollars per share)	$ 48.21				$ 41.66				$ 48.21	$ 41.66	$ 42.29
Restricted Stock [Member]
Restricted Stock [Roll Forward]
Balance, beginning of year (in shares)				227,213				284,245	227,213	284,245	175,488
Granted (in shares)									69,539	155,165	216,502
Exercised/vested (in shares)									(61,274)	(88,746)	(59,801)
Canceled (in shares)									(55,368)	(123,451)	(47,944)
Balance, end of year (in shares)	180,110				227,213				180,110	227,213	284,245
Weighted Average Exercise Price Per Share [Abstract]
Balance, beginning of year (in dollars per share)				$ 49.57				$ 58.63	$ 49.57	$ 58.63	$ 50.56
Granted (in dollars per share)									78	38.37	60.32
Exercised/vested (in dollars per share)									52.51	57.38	47.51
Canceled (in dollars per share)									52.74	50.72	51.43
Balance, end of year (in dollars per share)	$ 58.57				$ 49.57				$ 58.57	$ 49.57	$ 58.63

Accumulated Other Comprehensi77

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Cumulative foreign currency translation	$ (104.1)	$ (147.3)
Unrecognized pension costs (net of tax benefit of $30.7 in 2017 and $39.4 in 2016)	(86.5)	(78)
Unrealized gain (loss) on cash flow hedges (net of tax expense of $0.7 in 2017 and $1.8 in 2016)	4.5	4.2
Total accumulated other comprehensive income (loss)	(186.1)	(221.1)
Unrecognized pension costs, tax benefit	30.7	39.4
Unrealized gain (loss) on cash flow hedges, tax expense	0.7	1.8
Foreign currency translation adjustment [Abstract]
Foreign currency translation adjustment, pre-tax amount	44.7	(40.2)	$ (76.6)
Foreign currency translation adjustment, tax (expense) benefit	0	0	0
Foreign currency translation adjustments, net-of-tax amount	44.7	(40.2)	(76.6)
Pension plans [Abstract]
Net actuarial gains (losses) and prior service costs arising during the period, pre-tax amount	(17.6)	(12.5)	0.5
Net actuarial gains (losses) and prior service costs arising during the period, tax (expense) benefit	4.4	4.1	0.5
Net actuarial gains (losses) and prior service costs arising during the period, net-of-tax amount	(13.2)	(8.4)	1
Amortization of net actuarial (gains) losses and prior service costs, pre-tax amount	7.6	8	9.6
Amortization of net actuarial (gains) losses and prior service costs, tax (expense) benefit	(2.9)	(2.8)	(3.3)
Amortization of net actuarial (gains) losses and prior service costs, net-of-tax amount	4.7	5.2	6.3
Unrealized gains (losses) on cash flow hedges [Abstract]
Unrealized gains (losses) on cash flow hedges, pre-tax amount	0.2	2.4	0
Unrealized gains (losses) on cash flow hedges, tax (expense) benefit	0.1	(0.8)	0
Unrealized gains (losses) on cash flow hedges, net-of-tax amount	0.3	1.6	0
Total other comprehensive income (loss), pre-tax amount	34.9	(42.3)	(66.5)
Total other comprehensive income (loss)	1.6	0.5	(2.8)
Total other comprehensive income (loss), net of tax	$ 36.5	$ (41.8)	$ (69.3)

Accounting for Asset Retireme78

Accounting for Asset Retirement Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Asset retirement obligation [Roll Forward]
Asset retirement liability, beginning of period	$ 21.5	$ 21.4
Accretion expense	3.3	2.5
Payments	(3.2)	(1.6)
Foreign currency translation	0.5	(0.8)
Asset retirement liability, end of period	22.1	$ 21.5
Asset retirement obligation [Abstract]
Asset retirement obligation current portion	1.6
Asset retirement obligation noncurrent portion	$ 20.5

Segment and Related Informati79

Segment and Related Information (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017USD ($)	Oct. 01, 2017USD ($)	Jul. 02, 2017USD ($)	Apr. 02, 2017USD ($)	Dec. 31, 2016USD ($)	Oct. 02, 2016USD ($)	Jul. 03, 2016USD ($)	Apr. 03, 2016USD ($)	Dec. 31, 2017USD ($)Segment	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Segment and Related Information [Abstract]
Number of reportable segments | Segment									4
Segment Reporting Information [Line Items]
Net sales	$ 432.1	$ 424.5	$ 414.1	$ 405	$ 401.3	$ 399.5	$ 427	$ 410.2	$ 1,675.7	$ 1,638	$ 1,797.6
Income from operations	45.7	66.8	68.5	61.7	56.5	67.3	39.5	57.6	242.7	220.9	200.3
Depreciation, depletion and amortization									91	91.9	98.3
Segment assets	2,970.4				2,863.4				2,970.4	2,863.4	2,980
Capital expenditures									76.7	62.4	86
Income from operations before provision (benefit) for taxes on income [Abstract]
Acquisition related transaction and integration costs									(3.4)	(8)	(11.8)
Unallocated corporate expenses									(8.4)	(6)	(7)
Consolidated income from operations	45.7	66.8	68.5	61.7	56.5	67.3	39.5	57.6	242.7	220.9	200.3
Non-operating deductions, net									(51.8)	(50.6)	(67.7)
Income from continuing operations before provision (benefit) for taxes on income									190.9	170.3	132.6
Specialty Minerals [Member]
Segment Reporting Information [Line Items]
Net sales	143.9	147.7	147	146.2	138	147.3	150.6	155.6
Performance Materials [Member]
Segment Reporting Information [Line Items]
Net sales	195.8	188.8	180.3	169.9	175	169	182.5	159.6
Refractories [Member]
Segment Reporting Information [Line Items]
Net sales	71.3	69	68.9	70.2	68	63.4	73.9	69.2
Energy Services [Member]
Segment Reporting Information [Line Items]
Net sales	21.1	$ 19	$ 17.9	$ 18.7	20.3	$ 19.8	$ 20	$ 25.8
Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net sales									1,675.7	1,638	1,797.6
Income from operations									254.5	234.9	219.1
Depreciation, depletion and amortization									91	91.9	98.3
Segment assets	2,927				2,821.9				2,927	2,821.9	2,918.1
Capital expenditures									76.1	60.5	85.2
Income from operations before provision (benefit) for taxes on income [Abstract]
Consolidated income from operations									254.5	234.9	219.1
Reportable Segments [Member] | Specialty Minerals [Member]
Segment Reporting Information [Line Items]
Net sales									584.8	591.5	624.6
Income from operations									88.9	102.7	100.8
Depreciation, depletion and amortization									35.5	34.9	34
Segment assets	519.4				491.7				519.4	491.7	505.3
Capital expenditures									32.6	40.4	51.9
Income from operations before provision (benefit) for taxes on income [Abstract]
Consolidated income from operations									88.9	102.7	100.8
Reportable Segments [Member] | Performance Materials [Member]
Segment Reporting Information [Line Items]
Net sales									734.8	686.1	694.9
Income from operations									119.7	121.1	118.4
Depreciation, depletion and amortization									40.5	38.9	39.4
Segment assets	1,989.6				1,942.1				1,989.6	1,942.1	1,965.4
Capital expenditures									33.1	12.8	11.1
Income from operations before provision (benefit) for taxes on income [Abstract]
Consolidated income from operations									119.7	121.1	118.4
Reportable Segments [Member] | Refractories [Member]
Segment Reporting Information [Line Items]
Net sales									279.4	274.5	295.9
Income from operations									39.8	37	27.8
Depreciation, depletion and amortization									6.8	6.9	7.5
Segment assets	307.4				283.4				307.4	283.4	292.7
Capital expenditures									5.9	5.9	11.1
Income from operations before provision (benefit) for taxes on income [Abstract]
Consolidated income from operations									39.8	37	27.8
Reportable Segments [Member] | Energy Services [Member]
Segment Reporting Information [Line Items]
Net sales									76.7	85.9	182.2
Income from operations									6.1	(25.9)	(27.9)
Depreciation, depletion and amortization									8.2	11.2	17.4
Segment assets	110.6				104.7				110.6	104.7	154.7
Capital expenditures									4.5	1.4	11.1
Income from operations before provision (benefit) for taxes on income [Abstract]
Consolidated income from operations									6.1	(25.9)	(27.9)
Corporate [Member]
Segment Reporting Information [Line Items]
Segment assets	$ 43.4				$ 41.5				43.4	41.5	61.9
Capital expenditures									$ 0.6	$ 1.9	$ 0.8

Segment and Related Informati80

Segment and Related Information, Sales By Region Category (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2016	Oct. 02, 2016	Jul. 03, 2016	Apr. 03, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 432.1	$ 424.5	$ 414.1	$ 405	$ 401.3	$ 399.5	$ 427	$ 410.2	$ 1,675.7	$ 1,638	$ 1,797.6
Long-lived assets	2,037.1				2,034.8				2,037.1	2,034.8	2,098.2
Total International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									736.4	701.8	748
Long-lived assets	262.7				240.3				262.7	240.3	268.9
Reportable Geographical Components [Member] | United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									939.3	936.2	1,049.6
Long-lived assets	1,774.4				1,794.5				1,774.4	1,794.5	1,829.3
Reportable Geographical Components [Member] | Canada/Latin America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									81.6	82.6	86.3
Long-lived assets	14.8				14.8				14.8	14.8	13
Reportable Geographical Components [Member] | Europe/Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									349	338.8	382.1
Long-lived assets	115.9				98.2				115.9	98.2	117.6
Reportable Geographical Components [Member] | Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									305.8	280.4	279.6
Long-lived assets	$ 132				$ 127.3				$ 132	$ 127.3	$ 138.3

Segment and Related Informati81

Segment and Related Information, Sales by Product Category (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2016	Oct. 02, 2016	Jul. 03, 2016	Apr. 03, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue from External Customer [Line Items]
Net sales	$ 432.1	$ 424.5	$ 414.1	$ 405	$ 401.3	$ 399.5	$ 427	$ 410.2	$ 1,675.7	$ 1,638	$ 1,797.6
Paper PCC [Member]
Revenue from External Customer [Line Items]
Net sales									377.7	387.9	423.3
Specialty PCC [Member]
Revenue from External Customer [Line Items]
Net sales									66	64.3	64.8
Talc [Member]
Revenue from External Customer [Line Items]
Net sales									53.8	55.7	55.9
Ground Calcium Carbonate [Member]
Revenue from External Customer [Line Items]
Net sales									87.3	83.6	80.6
Metalcasting [Member]
Revenue from External Customer [Line Items]
Net sales									294.3	258	266.4
Household, Personal Care & Specialty Products [Member]
Revenue from External Customer [Line Items]
Net sales									169.6	171.2	172.7
Basic Minerals [Member]
Revenue from External Customer [Line Items]
Net sales									125	103.9	106
Environmental Products [Member]
Revenue from External Customer [Line Items]
Net sales									67.7	78.9	69.8
Building Materials [Member]
Revenue from External Customer [Line Items]
Net sales									78.2	74.1	80
Refractory Products [Member]
Revenue from External Customer [Line Items]
Net sales									226.9	219	230.7
Metallurgical Products [Member]
Revenue from External Customer [Line Items]
Net sales									52.5	55.5	65.2
Energy Services [Member]
Revenue from External Customer [Line Items]
Net sales									$ 76.7	$ 85.9	$ 182.2

Quarterly Financial Data (una82

Quarterly Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2016	Oct. 02, 2016	Jul. 03, 2016	Apr. 03, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue from External Customer [Line Items]
Net sales	$ 432.1	$ 424.5	$ 414.1	$ 405	$ 401.3	$ 399.5	$ 427	$ 410.2	$ 1,675.7	$ 1,638	$ 1,797.6
Gross profit	114.5	119.3	119.7	113.7	111.4	115.2	121.1	112.7	467.2	460.4	471
Income from operations	45.7	66.8	68.5	61.7	56.5	67.3	39.5	57.6	242.7	220.9	200.3
Consolidated net income	76.7	42.8	43.8	35.6	37.5	42.5	22.3	34.8	199	137.1	111.6
Net income attributable to Minerals Technologies Inc. (MTI)	$ 75.8	$ 41.7	$ 43	$ 34.6	$ 36.7	$ 41.6	$ 21.2	$ 33.9	$ 195.1	$ 133.4	$ 107.9
Basic earnings per share attributable to MTI shareholders (in dollars per share)	$ 2.14	$ 1.18	$ 1.23	$ 0.99	$ 1.05	$ 1.19	$ 0.61	$ 0.97	$ 5.54	$ 3.82	$ 3.11
Diluted earnings per share attributable to MTI shareholders (in dollars per share)	2.12	1.17	1.21	0.97	1.04	1.18	0.60	0.97	5.48	3.79	$ 3.08
Market price range per share of common stock [Abstract]
High (in dollars per share)	73.55	75.60	80.20	83.70	82.90	72.51	61.66	57.12
Low (in dollars per share)	66.40	62.95	70.50	72.20	66.10	56	52.53	37.03
Close (in dollars per share)	68.85	70.65	73.20	76.60	77.25	70.69	57.38	57.12	68.85	$ 77.25
Dividends paid per common share (in dollars per share)	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.20
Specialty Minerals [Member]
Revenue from External Customer [Line Items]
Net sales	$ 143.9	$ 147.7	$ 147	$ 146.2	$ 138	$ 147.3	$ 150.6	$ 155.6
Performance Materials [Member]
Revenue from External Customer [Line Items]
Net sales	195.8	188.8	180.3	169.9	175	169	182.5	159.6
Refractories [Member]
Revenue from External Customer [Line Items]
Net sales	71.3	69	68.9	70.2	68	63.4	73.9	69.2
Energy Services [Member]
Revenue from External Customer [Line Items]
Net sales	$ 21.1	$ 19	$ 17.9	$ 18.7	$ 20.3	$ 19.8	$ 20	$ 25.8

SCHEDULE II-VALUATION AND QUA83

SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS (Details) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		$ 7.9	$ 4.4	$ 3.6
Additions Charged to Costs, Provisions and Expenses		3.8	6.2	2.6
Deductions	[1]	(7.5)	(2.7)	(1.8)
Balance at End of Period		$ 4.2	$ 7.9	$ 4.4
[1]	Includes impact of translation of foreign currencies.