Materion (MTRN) 10-K 18 Feb 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Jan. 29, 2021	Jun. 26, 2020
Document and Entity Information [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	1-15885
Entity Registrant Name	MATERION CORPORATION
Entity Incorporation, State or Country Code	OH
Entity Tax Identification Number	34-1919973
Entity Address, Address Line One	6070 Parkland Blvd
Entity Address, City or Town	Mayfield Heights
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	44124
City Area Code	216
Local Phone Number	486-4200
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	MTRN
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,175,158,375
Entity Common Stock, Shares Outstanding		20,330,126
Entity Central Index Key	0001104657
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Documents Incorporated by Reference	Portions of the Proxy Statement for the 2021 Annual Meeting of Shareholders are incorporated by reference into Part III.

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Net sales	$ 1,176,274,000	$ 1,185,424,000	$ 1,207,815,000
Cost of sales	983,641,000	922,734,000	956,454,000
Gross margin	192,633,000	262,690,000	251,361,000
Selling, general, and administrative expense	133,963,000	147,164,000	153,489,000
Research and development expense	20,283,000	18,271,000	15,187,000
Goodwill impairment charges	9,053,000	11,560,000	0
Asset impairment charges	1,419,000	2,581,000	0
Restructuring expense	11,237,000	785,000	5,599,000
Other - net	8,463,000	11,783,000	15,334,000
Operating profit	8,215,000	70,546,000	61,752,000
Other non-operating (income) expense-net	(3,939,000)	3,431,000	42,683,000
Interest expense - net	3,879,000	1,579,000	2,471,000
Income before income taxes	8,275,000	65,536,000	16,598,000
Income tax (benefit) expense	(7,187,000)	12,142,000	(4,446,000)
Net income	$ 15,462,000	$ 53,394,000	$ 21,044,000
Basic earnings per share:
Net income per share of common stock (in usd per share)	$ 0.76	$ 2.62	$ 1.04
Diluted earnings per share:
Net income per share of common stock (in usd per share)	$ 0.75	$ 2.59	$ 1.02
Weighted-average number of shares of common stock outstanding:
Basic	20,338	20,365	20,212
Diluted	20,603	20,655	20,613

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 15,462	$ 53,394	$ 21,044
Other comprehensive income:
Foreign currency translation adjustment	9,030	(421)	(484)
Derivative and hedging activity, net of tax (expense) benefit of $28, $5, and $672	(80)	(4)	138
Pension and post-employment benefit adjustment, net of tax benefit (expense) of $651, ($4,741), and ($13,300)	(2,127)	13,197	45,049
Other comprehensive income	6,823	12,772	44,703
Comprehensive income	$ 22,285	$ 66,166	$ 65,747

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Derivative and hedging activity, tax benefit	$ 28	$ 5	$ 672
Pension and post employment benefit adjustment, tax benefit (expense)	$ 651	$ (4,741)	$ (13,300)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 15,462	$ 53,394	$ 21,044
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, and amortization	42,384	41,116	35,524
Amortization of deferred financing costs in interest expense	790	962	1,009
Stock-based compensation expense (non-cash)	5,528	7,170	5,313
Amortization of pension and post-retirement costs	(151)	386	5,551
Loss on sale of property, plant, and equipment	466	344	518
Deferred income tax (benefit) expense	(9,850)	3,945	(1,912)
Impairment charges	10,472	14,141	0
Net pension curtailments and settlements	94	3,328	41,406
Changes in assets and liabilities net of acquired assets and liabilities:
Decrease (increase) in accounts receivable	(707)	(23,933)	(7,219)
Decrease (increase) in inventory	(1,288)	20,485	3,978
Decrease (increase) in prepaid and other current assets	2,475	869	1,814
Increase (decrease) in accounts payable and accrued expenses	(21,877)	(18,575)	8,820
Increase (decrease) in unearned revenue	2,935	(2,538)	477
Increase (decrease) in interest and taxes payable	(157)	(805)	435
Increase (decrease) in unearned income due to customer prepayments	54,103	4,733	0
Domestic pension plan contributions	0	(4,500)	(42,000)
Other — net	378	(1,300)	1,616
Net cash provided by operating activities	101,057	99,222	76,374
Cash flows from investing activities:
Payments for acquisition, net of cash acquired	(130,715)	0	0
Payments for purchase of property, plant, and equipment	(67,274)	(24,251)	(27,702)
Payments for mine development	0	(2,277)	(6,558)
Proceeds from settlement of currency exchange contract	3,249	0	0
Proceeds from sale of property, plant, and equipment	33	44	432
Net cash used in investing activities	(194,707)	(26,484)	(33,828)
Cash flows from financing activities:
Proceeds from short-term debt under revolving credit agreement, net	34,000	0	0
Repayment of long-term debt	(20,634)	(823)	(777)
Principal payments under finance lease obligations	(2,213)	(1,200)	(861)
Cash dividends paid	(9,257)	(8,856)	(8,389)
Deferred financing costs	0	(2,130)	0
Repurchase of common stock	(6,766)	(199)	(422)
Payments of withholding taxes for stock-based compensation awards	(2,221)	(4,846)	(3,156)
Net cash used in financing activities	(7,091)	(18,054)	(13,605)
Effects of exchange rate changes	1,612	(322)	(140)
Net change in cash and cash equivalents	(99,129)	54,362	28,801
Cash and cash equivalents at beginning of period	125,007	70,645	41,844
Cash and cash equivalents at end of period	$ 25,878	$ 125,007	$ 70,645

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 25,878	$ 125,007
Accounts receivable	166,447	154,751
Inventories	250,778	236,253
Prepaid and other current assets	20,896	21,736
Total current assets	463,999	537,747
Deferred income taxes	3,134	1,666
Property, plant, and equipment	998,312	916,965
Less allowances for depreciation, depletion, and amortization	(688,626)	(684,689)
Property, plant, and equipment — net	309,686	232,276
Operating lease, right-of-use assets	62,089	23,413
Intangible assets	54,672	6,380
Other assets	19,364	17,937
Goodwill	144,916	79,011
Total Assets	1,057,860	898,430
Current liabilities
Short-term debt	1,937	868
Accounts payable	55,640	43,206
Salaries and wages	18,809	41,167
Other liabilities and accrued items	40,887	32,477
Income taxes	1,898	1,342
Unearned revenue	7,713	3,380
Total current liabilities	126,884	122,440
Other long-term liabilities	14,313	11,560
Operating lease liabilities	56,761	18,091
Finance lease liabilities	20,539	17,424
Retirement and post-employment benefits	41,877	32,466
Unearned income	86,761	32,891
Long-term income taxes	2,689	3,451
Deferred income taxes	15,864	13,104
Long-term debt	36,542	1,260
Shareholders’ equity
Serial preferred stock (no par value; 5,000 authorized shares, none issued)	0	0
Common stock (no par value; 60,000 authorized shares, issued shares of 27,148 for both 2020 and 2019)	258,642	249,674
Retained earnings	631,058	624,954
Common stock in treasury (6,820 shares for 2020 and 6,744 shares for 2019)	(199,187)	(186,845)
Accumulated other comprehensive loss	(38,639)	(45,462)
Other equity	3,756	3,422
Total shareholders’ equity	655,630	645,743
Total Liabilities and Shareholders’ Equity	$ 1,057,860	$ 898,430

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Thousands, $ / shares in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Serial preferred stock, par value (in dollars per share)	$ 0	$ 0
Serial preferred stock, shares authorized	5,000	5,000
Serial preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized	60,000	60,000
Common stock, shares, issued	27,148	27,148
Treasury stock, shares	6,820	6,744

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Previously Reported	Revision of Prior Period, Adjustment	Common Shares	Common SharesPreviously Reported	Common Shares Held In Treasury	Common Shares Held In TreasuryPreviously Reported	Common Stock	Common StockPreviously Reported	Retained Earnings	Retained EarningsCumulative Effect, Period of Adoption, Adjustment	Retained EarningsPreviously Reported	Retained EarningsRevision of Prior Period, Adjustment	Common Stock In Treasury	Common Stock In TreasuryPreviously Reported	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss)Previously Reported	Other Equity Transactions	Other Equity TransactionsPreviously Reported
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares				20,107	20,107
Common shares held in Treasury						7,042	7,042
Retained earnings | Accounting Standards Update 2014-09	$ 425										$ 425
Beginning balances at Dec. 31, 2017	527,115	$ 494,981	$ 32,134					$ 223,484	$ 223,484	$ 568,250		$ 536,116	$ 32,134	$ (166,128)	$ (166,128)	$ (102,937)	$ (102,937)	$ 4,446	$ 4,446
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	21,044	20,846						0		21,044				0		0		0
Other comprehensive income	2,722							0		0				0		2,722		0
Net pension curtailments and settlements	41,406							0		0				0		41,406		0
Tax Cuts and Jobs Act Reclassification	$ 0							0		(575)				0		575		0
Accounting Standards Update [Extensible List] | Accounting Standards Update 2014-09	us-gaap:AccountingStandardsUpdate201409Member
Cash dividends declared	$ (8,389)							0		(8,389)				0		0		0
Stock-based compensation activity, in shares				202		(203)
Stock-based compensation activity	5,314							11,131		(49)				(5,768)		0		0
Payments for withholding taxes for stock-based compensation awards, in shares				(60)		60
Payments for withholding taxes for stock-based compensation awards	(3,156)							0		0				(3,156)		0		0
Repurchase of shares				(10)		10
Repurchase of 10, 5, and 158 shares for the years ended 2018, 2019, and 2020, respectively	(422)							0		0				(422)		0		0
Directors' deferred compensation, in shares				3		(3)
Directors' deferred compensation	179							89		0				48		0		42
Ending balances at Dec. 31, 2018	586,238							234,704		580,706				(175,426)		(58,234)		4,488
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares				20,242
Common shares held in Treasury						6,906
Retained earnings | Accounting Standards Update 2016-02	(179)										$ (179)
Net income	53,394	50,660						0		53,394				0		0		0
Other comprehensive income	9,444							0		0				0		9,444		0
Net pension curtailments and settlements	$ 3,328							0		0				0		3,328		0
Accounting Standards Update [Extensible List] | Accounting Standards Update 2016-02	us-gaap:AccountingStandardsUpdate201602Member
Cash dividends declared	$ (8,856)							0		(8,856)				0		0		0
Stock-based compensation activity, in shares				252		(252)
Stock-based compensation activity	7,170							14,876		(111)				(7,595)		0		0
Payments for withholding taxes for stock-based compensation awards, in shares				(89)		89
Payments for withholding taxes for stock-based compensation awards	(4,846)							0		0				(4,846)		0		0
Repurchase of shares				(5)		5
Repurchase of 10, 5, and 158 shares for the years ended 2018, 2019, and 2020, respectively	(199)							0		0				(199)		0		0
Directors' deferred compensation, in shares				4		(4)
Directors' deferred compensation	249							94		0				1,221		0		(1,066)
Ending balances at Dec. 31, 2019	$ 645,743							249,674		624,954				(186,845)		(45,462)		3,422
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares				20,404
Common shares held in Treasury	6,744					6,744
Retained earnings	$ 624,954
Net income	15,462	$ 16,942						0		15,462				0		0		0
Other comprehensive income	6,729							0		0				0		6,729		0
Net pension curtailments and settlements	94							0		0				0		94		0
Cash dividends declared	(9,257)							0		(9,257)				0		0		0
Stock-based compensation activity, in shares				117		(117)
Stock-based compensation activity	5,619							8,867		(101)				(3,147)		0		0
Payments for withholding taxes for stock-based compensation awards, in shares				(39)		39
Payments for withholding taxes for stock-based compensation awards	(2,221)							0		0				(2,221)		0		0
Repurchase of shares				(158)		158
Repurchase of 10, 5, and 158 shares for the years ended 2018, 2019, and 2020, respectively	(6,766)							0		0				(6,766)		0		0
Directors' deferred compensation, in shares				4		(4)
Directors' deferred compensation	227							101		0				(208)		0		334
Ending balances at Dec. 31, 2020	$ 655,630							$ 258,642		$ 631,058				$ (199,187)		$ (38,639)		$ 3,756
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares				20,328
Common shares held in Treasury	6,820					6,820
Retained earnings	$ 631,058

Consolidated Statements of Sh_2

Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Cash dividends per share	$ 0.455	$ 0.435	$ 0.415

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Organization: Materion Corporation (the Company) is a holding company with subsidiaries that have operations in the United States, Europe, and Asia. These operations manufacture advanced engineered materials used in a variety of end markets, including semiconductor, industrial, aerospace and defense, automotive, energy, consumer electronics, and telecom and data center. The Company has four reportable segments: Performance Alloys and Composites, Advanced Materials, Precision Optics, and Other. Other includes unallocated corporate costs. Refer to Note C for additional segment details. The Company distributes its products through a combination of company-owned facilities and independent distributors and agents. Business Combinations: The Company records assets acquired and liabilities assumed at the date of acquisition at their respective fair values. Intangible assets acquired in a business combination are recognized and reported apart from goodwill. Goodwill represents the excess purchase price over the fair value of the tangible net assets and intangible assets acquired in a business combination. Acquisition-related expenses are recognized separately from the business combination and are expensed as incurred. The amounts reflected in Note B to the Consolidated Financial Statements are the results of the preliminary purchase price allocation for the Optics Balzers acquisition and will be updated upon completion of the final valuation. The Company is required to complete the purchase price allocation within 12 months of the acquisition date. If such completion of the allocation results in a change in the preliminary values, the measurement period adjustment will be recognized in the period in which the adjustment amount is determined. Use of Estimates: The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results may differ from those estimates. Change in Accounting Principle: During the fourth quarter of 2020, the Company changed its method of accounting for certain domestic inventory from the last-in, first-out (LIFO) method to the first-in, first-out (FIFO) method. All prior periods presented have been retroactively adjusted to apply the new method of accounting. Consolidation: The Consolidated Financial Statements include the accounts of Materion Corporation and its subsidiaries. All of the Company’s subsidiaries were wholly owned as of December 31, 2020. Intercompany accounts and transactions are eliminated in consolidation. Cash Equivalents: All highly liquid investments with a maturity of three months or less when purchased are considered to be cash equivalents. Accounts Receivable: An allowance for doubtful accounts is maintained for the expected losses resulting from the inability of customers to pay amounts due. The Company considers the current market conditions and credit losses related to the Company's trade receivables based on the macroeconomic environment, geographic considerations, and other expected market trends. Additionally, the allowance is based upon identified delinquent accounts, customer payment patterns, and other analyses of historical data and trends. Accounts receivable were net of an allowance for credit losses of $0.5 million and $0.4 million at December 31, 2020 and 2019, respectively. The change in the allowance for credit losses includes expense and net write-offs, none of which are material. The Company extends credit to customers based upon their financial condition, and collateral is not generally required. Property, Plant, and Equipment: Property, plant, and equipment is stated on the basis of cost. Depreciation is computed principally by the straight-line method, except certain assets for which depreciation may be computed by the units-of-production method. The depreciable lives that are used in computing the annual provision for depreciation by class of asset are primarily as follows: Years Land improvements 10 to 20 Buildings 20 to 40 Leasehold improvements Life of lease Machinery and equipment 3 to 15 Furniture and fixtures 4 to 10 Automobiles and trucks 3 to 8 Research equipment 3 to 10 Computer hardware 3 to 10 Computer software 3 to 10 An asset acquired under a finance lease will be recorded at the lesser of the present value of the projected lease payments or the fair value of the asset and will be depreciated in accordance with the above schedule. Leasehold improvements will be depreciated over the life of the improvement if it is shorter than the life of the lease. Repair and maintenance costs are expensed as incurred. Mineral Resources and Mine Development: Property acquisition costs are capitalized as mineral resources on the balance sheet and are depleted using the units-of-production method based upon total estimated recoverable proven reserves of the beryllium-bearing bertrandite ore body. The Company uses beryllium pounds as the unit of accounting measure, and depletion expense is recorded on a pro-rata basis based upon the amount of beryllium pounds extracted as a percentage of total estimated beryllium pounds contained in all ore bodies. Mine development costs at the Company's open pit surface mine include drilling, infrastructure, and other related costs to delineate an ore body, and the removal of overburden to initially expose an ore body. Before mineralization is classified as proven and probable reserves, costs are classified as exploration expense. Capitalization of mine development project costs that meet the definition of an asset begins once mineralization is classified as proven and probable reserves. Historically, the Company’s mine development costs involved the development of a new source of ore, and, as such, mine development costs incurred were capitalized during the pre-production phase of a mine and amortized into inventory as the ore was extracted. In 2020, the Company expanded a mine to further develop an ore body. Since the pre-production phase ended when ore was first extracted from this mine, the Company recognized approximately $12.9 million of mine development costs in 2020 as a component of cost of sales. This expansion is expected to benefit future periods. Drilling and related costs are capitalized for an ore body where proven and probable reserves exist, and the activities are directed at obtaining additional information on the ore body. All other drilling and related costs are expensed as incurred. Drilling costs incurred during the production phase for operational ore control are allocated to inventory costs and then included as a component of costs applicable to sales. The costs of removing overburden and waste materials to access the ore body at an open-pit mine prior to the production phase are capitalized during the development of an open-pit mine and are capitalized at each pit. These costs are amortized as the ore is extracted using the units-of-production method based upon total estimated recoverable proven reserves for the individual pit. The Company uses beryllium pounds as the unit of accounting measure for recording amortization. To the extent that the aforementioned costs benefit an entire ore body, the costs are amortized over the estimated useful life of the ore body. Costs incurred to access specific ore blocks or areas that only provide benefit over the life of that area are amortized over the estimated life of that specific ore block area. Goodwill and Other Intangible Assets: Goodwill is reviewed annually for impairment or more frequently if impairment indicators arise. The Company conducts its annual goodwill and indefinite-lived intangible asset impairment assessment as of the first day of the fourth quarter, or more frequently under certain circumstances. For the purpose of the goodwill impairment assessment, the Company has the option to perform a qualitative assessment (commonly referred to as "step zero") to determine whether further quantitative analysis for impairment of goodwill or indefinite-lived intangible assets is necessary or a quantitative assessment ("step one") where the Company estimates the fair value of each reporting unit using a discounted cash flow method (income approach). Goodwill is assigned to the reporting unit, which is the operating segment level or one level below the operating segment. Intangible assets with finite lives are amortized using the straight-line method or effective interest method, as applicable, over the periods estimated to be benefited, which is generally 20 years or less. Finite-lived intangible assets are also reviewed for impairment if facts and circumstances warrant. Long-Lived Asset Impairment: Management performs impairment tests of long-lived assets, including property and equipment, whenever an event occurs or circumstances change that indicate that the carrying value may not be recoverable or the useful life of the asset has changed. Upon indications of impairment, assets and liabilities are grouped at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities. The asset group would be considered impaired when the estimated future undiscounted cash flows generated by the asset group are less than its carrying value. If such undiscounted cash flows indicate that the carrying value of the asset group is not recoverable, impairment losses are measured by comparing the estimated fair value of the asset group to its carrying amount. Derivatives: The Company recognizes all derivatives on the balance sheet at fair value. If the derivative is designated and effective as a cash flow hedge, changes in the fair value of the derivative are recognized in other comprehensive income, a component of shareholders’ equity, until the hedged item is recognized in earnings. If the derivative is designated as a fair value hedge, changes in fair value are offset against the change in the fair value of the hedged asset, liability, or commitment through earnings. The ineffective portion of a derivative’s change in fair value, if any, is recognized in earnings immediately. If a derivative is not a hedge, changes in its fair value are adjusted through the income statement. Asset Retirement Obligation: The Company records a liability to recognize the legal obligation to remove an asset at the time the asset is acquired or when the legal liability arises. The liability is recorded for the present value of the ultimate obligation by discounting the estimated future cash flows using a credit-adjusted risk-free interest rate. The liability is accreted over time, with the accretion charged to expense. An asset equal to the fair value of the liability is recorded concurrent with the liability and depreciated over the life of the underlying asset. Unearned Income: Expenditures for capital equipment to be reimbursed under government contracts are recorded in property, plant, and equipment, while the reimbursements for those expenditures are recorded in unearned income, a liability on the balance sheet. When the assets subject to reimbursement are placed in service, the total cost is depreciated over the useful lives, and the unearned income liability is reduced and credited to cost of sales on the Consolidated Statements of Income ratably with the annual depreciation expense. Also included in Unearned Income as of December 31, 2020 are $58.8 million of customer prepayments. See Note L for additional discussion. Advertising Costs: The Company expenses all advertising costs as incurred. Advertising costs were $0.3 million in 2020, $0.7 million in 2019, and $1.2 million in 2018. Stock-based Compensation: The Company recognizes stock-based compensation expense based on the grant date fair value of the award over the period during which an employee is required to provide service in exchange for the award. Stock-based awards include performance-based restricted stock units (PRSUs), restricted stock units (RSUs), and stock appreciation rights (SARs). The fair value of PRSUs and RSUs is primarily based on the closing market price of a share of the Company's common stock on the date of grant, modified as appropriate to take into account the features of such grants. SARs are granted with an exercise price equal to the closing price of the Company's common shares on the date of grant. The fair value of SARs is determined using a Black-Scholes option-pricing model, which incorporates assumptions regarding the expected volatility, the expected option life, the risk-free interest rate, and the expected dividend yield. See Note R for additional information about stock-based compensation. Capitalized Interest: Interest expense associated with active capital asset construction and mine development projects is capitalized and amortized over the future useful lives of the related assets. Income Taxes: The Company uses the liability method in measuring the provision for income taxes and recognizing deferred tax assets and liabilities on the balance sheet. The Company will record a valuation allowance to reduce the deferred tax assets to the amount that is more likely than not to be realized, as warranted by current facts and circumstances. The Company applies a more-likely-than-not recognition threshold for all tax uncertainties and will record a liability for those tax benefits that have a less than 50% likelihood of being sustained upon examination by the taxing authorities. Net Income Per Share: Basic earnings per share (EPS) is computed by dividing income available to common stockholders by the weighted-average number of common shares outstanding for the period. Diluted EPS reflects the assumed conversion of all dilutive common stock equivalents as appropriate using the treasury stock method. New Pronouncements Adopted: In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-13, Financial Instruments - Credit Losses . This ASU requires an entity to change its accounting approach in determining impairment of certain financial instruments, including trade receivables, from an “incurred loss” to a “current expected credit loss” model. The standard is effective for fiscal years beginning after December 15, 2019, including interim periods within such fiscal years. The Company adopted this guidance as of January 1, 2020, and the adoption did not have a material effect on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU 2018-14 Defined Benefit Plans (Topic 715-20) - Changes to the Disclosure Requirements for Defined Benefit Plans, which intends to improve disclosure effectiveness by adding, removing, or clarifying certain disclosure requirements related to defined benefit pension or other postretirement plans . The standard is effective for fiscal years ending after December 15, 2020. The Company adopted this guidance as of December 31, 2020. The effect of the adoption did not materially impact the Company's financial statements or related disclosures. No other recently issued or effective ASUs had, or are expected to have, a material effect on the Company's results of operations, financial condition, or liquidity. Inventories: Inventories are stated at the lower of cost or net realizable value. In the fourth quarter of 2020, the Company voluntarily changed its method of inventory costing for the majority of its domestic inventories to the FIFO method from the LIFO method. Except for its bertrandite ore mine which values inventory using a weighted average cost method, the Company's remaining inventories are valued using the FIFO method. The Company believes that a current costing method is preferable as it improves comparability with its most similar peers, it more closely resembles the physical flow of its inventory (i.e., it provides better matching of revenues and expenses), and it results in uniformity across a significant majority of the Company’s inventory. Prior to the change in method, inventories valued on the LIFO cost method were approximately 45% of the Company's total inventories as of December 31, 2020. The effects of the change in accounting principle from LIFO to FIFO have been retrospectively applied to all periods presented. As a result of the retrospective application of the change in accounting principle, certain financial statement line items in the Company’s consolidated balance sheets as of December 31, 2019 and the consolidated statements of income, comprehensive income, shareholders’ equity, and cash flows for the years ended December 31, 2019 and 2018 were adjusted as necessary. As a result of the retrospective application of this change in accounting method, the following financial statement line items within the accompanying financial statements were adjusted, as follows: Consolidated Statements of Income (Thousands except per share amounts) 2020 2019 2018 Selected Items As Computed Under LIFO As Reported Under FIFO Difference Previously Reported As Adjusted Adjustment Previously Reported As Adjusted Adjustment Cost of sales $ 981,722 $ 983,641 $ 1,919 $ 926,280 $ 922,734 $ (3,546) $ 956,710 $ 956,454 $ (256) Gross margin 194,552 192,633 (1,919) 259,144 262,690 3,546 251,105 251,361 256 Operating profit 10,134 8,215 (1,919) 67,000 70,546 3,546 61,496 61,752 256 Income before income taxes 10,194 8,275 (1,919) 61,990 65,536 3,546 16,342 16,598 256 Income tax (benefit) expense (6,748) (7,187) (439) 11,330 12,142 812 (4,504) (4,446) 58 Net income 16,942 15,462 (1,480) 50,660 53,394 2,734 20,846 21,044 198 Basic earnings per share: Net income per share of common stock $ 0.83 $ 0.76 $ (0.07) $ 2.49 $ 2.62 $ 0.13 $ 1.03 $ 1.04 $ 0.01 Diluted earnings per share: Net income per share of common stock $ 0.82 $ 0.75 $ (0.07) $ 2.45 $ 2.59 $ 0.14 $ 1.01 $ 1.02 $ 0.01 Consolidated Statements of Comprehensive Income (Thousands) 2020 2019 2018 Selected Items As Computed Under LIFO As Reported Under FIFO Difference Previously Reported As Adjusted Adjustment Previously Reported As Adjusted Adjustment Net income $ 16,942 $ 15,462 $ (1,480) $ 50,660 $ 53,394 $ 2,734 $ 20,846 $ 21,044 $ 198 Comprehensive income 23,765 22,285 (1,480) 63,432 66,166 2,734 65,549 65,747 198 Consolidated Balance Sheets (Thousands) 2020 2019 Selected Items As Computed Under LIFO As Reported Under FIFO Difference Previously Reported As Adjusted Adjustment Inventories, net $ 206,834 $ 250,778 $ 43,944 $ 190,390 $ 236,253 $ 45,863 Prepaid and other current assets 23,470 20,896 (2,574) 21,839 21,736 (103) Deferred income taxes (liability) 8,081 15,864 7,783 2,410 13,104 10,694 Retained earnings 597,471 631,058 33,587 589,888 624,954 35,066 Consolidated Statements of Cash Flows (Thousands) 2020 2019 2018 Selected Items As Computed Under LIFO As Reported Under FIFO Difference Previously Reported As Adjusted Adjustment Previously Reported As Adjusted Adjustment Net income $ 16,942 $ 15,462 $ (1,480) $ 50,660 $ 53,394 $ 2,734 $ 20,846 $ 21,044 $ 198 Deferred income tax (benefit) expense (6,940) (9,850) (2,910) 2,584 3,945 1,361 (1,318) (1,912) (594) Decrease (increase) in inventory (3,207) (1,288) 1,919 24,031 20,485 (3,546) 4,234 3,978 (256) Decrease (increase) in prepaid and other current assets 4 2,475 2,471 1,418 869 (549) 1,162 1,814 652 As a result of the retrospective application of this change in accounting principle, the following financial statement line items within the unaudited interim 2020 and 2019 quarterly condensed consolidated financial statements were adjusted, as follows: Quarterly Data (unaudited) (Thousands except per share amounts) 2020 First Quarter Second Quarter Selected Items Previously Reported As Adjusted Adjustment Previously Reported As Adjusted Adjustment Cost of sales $ 232,371 $ 233,376 $ 1,005 $ 223,378 $ 224,513 $ 1,135 Gross margin 45,575 44,570 (1,005) 48,090 46,955 (1,135) Operating (loss) profit (4,563) (5,568) (1,005) 8,706 7,571 (1,135) (Loss) Income before income taxes (3,865) (4,870) (1,005) 8,298 7,163 (1,135) Income tax (benefit) expense (762) (992) (230) 1,620 1,360 (260) Net (loss) income (3,103) (3,878) (775) 6,678 5,803 (875) Basic earnings per share: Net (loss) income per share of common stock $ (0.15) $ (0.19) $ (0.04) $ 0.33 $ 0.29 $ (0.04) Diluted earnings per share: Net (loss) income per share of common stock $ (0.15) $ (0.19) $ (0.04) $ 0.32 $ 0.28 $ (0.04) (Thousands except per share amounts) 2020 Third Quarter Fourth Quarter Selected Items Previously Reported As Adjusted Adjustment As Computed Under LIFO As Reported Difference Cost of sales $ 240,531 $ 241,860 $ 1,329 $ 285,442 $ 283,892 $ (1,550) Gross margin 46,640 45,311 (1,329) 54,247 55,797 1,550 Operating (loss) profit 713 (616) (1,329) 5,278 6,828 1,550 (Loss) Income before income taxes 455 (874) (1,329) 5,306 6,856 1,550 Income tax (benefit) expense (6,041) (6,345) (304) (1,565) (1,210) 355 Net income 6,496 5,471 (1,025) 6,871 8,066 1,195 Basic earnings per share: Net income per share of common stock $ 0.32 $ 0.27 $ (0.05) $ 0.34 $ 0.40 $ 0.06 Diluted earnings per share: Net income per share of common stock $ 0.32 $ 0.27 $ (0.05) $ 0.33 $ 0.39 $ 0.06 (Thousands except per share amounts) 2019 First Quarter Second Quarter Selected Items Previously Reported As Adjusted Adjustment Previously Reported As Adjusted Adjustment Cost of sales $ 232,129 $ 231,835 $ (294) $ 228,249 $ 225,846 $ (2,403) Gross margin 69,312 69,606 294 69,594 71,997 2,403 Operating profit 21,387 21,681 294 22,750 25,153 2,403 Income before income taxes 20,676 20,970 294 19,138 21,541 2,403 Income tax expense 3,770 3,837 67 3,598 4,148 550 Net income 16,906 17,133 227 15,540 17,393 1,853 Basic earnings per share: Net income per share of common stock $ 0.83 $ 0.85 $ 0.02 $ 0.76 $ 0.85 $ 0.09 Diluted earnings per share: Net income per share of common stock $ 0.82 $ 0.83 $ 0.01 $ 0.75 $ 0.84 $ 0.09 (Thousands except per share amounts) 2019 Third Quarter Fourth Quarter Selected Items Previously Reported As Adjusted Adjustment Previously Reported As Adjusted Adjustment Cost of sales $ 240,748 $ 239,374 $ (1,374) $ 225,154 $ 225,679 $ 525 Gross margin 65,231 66,605 1,374 55,007 54,482 (525) Operating profit 6,289 7,663 1,374 16,574 16,049 (525) Income before income taxes 5,726 7,100 1,374 16,450 15,925 (525) Income tax expense 2,263 2,578 315 1,699 1,579 (120) Net income 3,463 4,522 1,059 14,751 14,346 (405) Basic earnings per share: Net income per share of common stock $ 0.17 $ 0.22 $ 0.05 $ 0.72 $ 0.70 $ (0.02) Diluted earnings per share: Net income per share of common stock $ 0.17 $ 0.22 $ 0.05 $ 0.71 $ 0.69 $ (0.02)

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Business Combination	Acquisition On July 17, 2020, the Company acquired 100% of the capital stock of Optics Balzers, an industry leader in thin film optical coatings. The purchase price for Optics Balzers was $136.1 million, including the assumption of $22.5 million of debt. The transaction was funded with cash on hand, including a portion of the $150.0 million borrowed under our revolving credit facility during the first half of 2020. This business operates within the Precision Optics segment, and the results of operations are included as of the date of acquisition. The combination of Materion and Optics Balzers creates a premier optical thin film coating solutions provider with a highly complementary geographic, product, and end market portfolio. The preliminary purchase price allocation for the acquisition is as follows: (Thousands) July 17, 2020 Assets: Cash and cash equivalents $ 5,390 Accounts receivable 8,484 Inventories 10,715 Prepaid and other current assets 937 Property, plant, and equipment 46,791 Operating lease, right-of-use assets 13,357 Intangible assets 49,300 Goodwill 70,639 Total assets acquired $ 205,613 Liabilities: Short-term debt $ 600 Accounts payable 2,851 Salaries and wages 4,392 Other liabilities and accrued items 3,678 Income taxes 61 Unearned revenue 1,259 Other long-term liabilities 207 Operating lease liabilities 12,356 Finance lease liabilities 2,642 Retirement and post-employment benefits 6,586 Unearned income 1,835 Long-term income taxes 181 Deferred income taxes 10,934 Long-term debt 21,926 Total liabilities assumed $ 69,508 Net assets acquired $ 136,105 Assets acquired and liabilities assumed are recognized at their respective fair values as of the acquisition date. The Company engaged specialists to assist in the valuation of property, plant, and equipment, intangible assets, and retirement and post-employment benefits. The estimates in the purchase price allocation are based on available information and will be revised during the measurement period, not to exceed 12 months, as additional information becomes available on tax-related items, and as additional analysis is performed. Such revisions are not expected to have a material impact on the Company's results of operations and financial position. No material measurement period adjustments have been recorded since the acquisition date. The Company's consolidated financial statements include the results of operations of Optics Balzers from the acquisition date through December 31, 2020. The amount of Net sales and operating results attributable to the acquisition during this period were not material. Acquisition-related transaction and integration costs totaled $6.5 million in 2020. These costs are included in selling, general, and administrative expense in the Consolidated Statements of Income. As part of the acquisition, the Company recorded approximately $70.6 million of goodwill in its Precision Optics segment. Goodwill was calculated as the excess of the purchase price over the estimated fair values of the tangible net assets and intangible assets acquired and primarily attributable to the synergies expected to arise after the acquisition dates. The goodwill is not expected to be deductible for U.S. tax purposes. The following table reports the intangible assets by asset category as of the closing date: (Thousands) Value at Acquisition Weighted Average Life Customer relationships $ 40,141 18 years Technology 4,059 5 years Licenses and other 5,100 5 years Total $ 49,300

Segment Reporting and Geographi

Segment Reporting and Geographic Information	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment Reporting and Geographic Information	Segment Reporting and Geographic Information Certain amounts below have been adjusted to reflect the retrospective application of the Company's change in inventory accounting method, as described in Note A. The Company has the following operating segments: Performance Alloys and Composites, Advanced Materials, Precision Optics, and Other. The Company’s operating segments represent components of the Company for which separate financial information is available that is utilized on a regular basis by the Chief Executive Officer, the Company's Chief Operating Decision Maker, in determining how to allocate the Company’s resources and evaluate performance. The segments are determined based on several factors, including the availability of discrete financial information and the Company’s organizational and management structure. Performance Alloys and Composites provides advanced engineered solutions comprised of beryllium and non-beryllium containing alloy systems and custom engineered parts in strip, bulk, rod, plate, bar, tube, and other customized shapes. Advanced Materials produces advanced chemicals, microelectric packaging, precious metal, non-precious metal, and specialty metal products, including vapor deposition targets, frame lid assemblies, clad and precious metal preforms, high temperature braze materials, and ultra-fine wire. Precision Optics produces thin film coatings, optical filter materials, sputter-coated, and precision-converted thin film materials. The Other reportable segment includes unallocated corporate costs and assets. Financial information for reportable segments was as follows: (Thousands) Performance Advanced Materials Precision Optics Other Total 2020 Net sales $ 394,195 $ 670,867 $ 111,212 $ — $ 1,176,274 Intersegment sales 6 35,912 — — 35,918 Operating profit (loss) 13,597 22,120 (4,382) (23,120) 8,215 Depreciation, depletion, and amortization 25,782 8,061 6,564 1,977 42,384 Expenditures for long-lived assets 53,841 9,003 908 3,522 67,274 Total Assets 477,892 251,637 268,004 60,327 1,057,860 2019 Net sales $ 500,201 $ 573,763 $ 111,460 $ — $ 1,185,424 Intersegment sales 38 70,047 — — 70,085 Operating profit (loss) 73,815 25,124 (3,550) (24,843) 70,546 Depreciation, depletion, and amortization 24,437 8,955 5,695 2,029 41,116 Expenditures for long-lived assets 15,520 7,572 1,045 2,391 26,528 Total Assets 442,885 214,961 78,981 161,603 898,430 2018 Net sales $ 500,590 $ 586,643 $ 120,582 $ — $ 1,207,815 Intersegment sales 37 50,460 — — 50,497 Operating profit (loss) 60,008 16,732 10,707 (25,695) 61,752 Depreciation, depletion, and amortization 17,434 8,575 7,066 2,449 35,524 Expenditures for long-lived assets 15,396 15,523 1,983 1,358 34,260 Total Assets 453,345 206,393 90,537 93,035 843,310 Intersegment sales are eliminated in consolidation. The primary measure of evaluating segment performance is operating profit. From an assets perspective, segments are evaluated based upon a return on invested capital metric, which includes inventory, accounts receivable, and property, plant, and equipment. A reconciliation of total segment operating profit to total consolidated income before income taxes is as follows: (Thousands) 2020 2019 2018 Total operating profit for reportable segments 8,215 70,546 61,752 Other non-operating (income) expense - net (3,939) 3,431 42,683 Interest expense - net 3,879 1,579 2,471 Income before income taxes $ 8,275 $ 65,536 $ 16,598 Other geographic information includes the following: (Thousands) 2020 2019 2018 Net sales United States $ 641,727 $ 743,345 $ 726,881 Asia 329,968 256,114 270,672 Europe 189,281 169,132 186,081 All other 15,298 16,833 24,181 Total $ 1,176,274 $ 1,185,424 $ 1,207,815 Property, plant, and equipment, net by country deployed United States $ 223,340 $ 194,596 $ 215,395 All other 86,346 37,680 35,623 Total $ 309,686 $ 232,276 $ 251,018 International sales include sales from international operations and direct exports from our U.S. operations. No individual country, other than the United States, or customer accounted for 10% or more of the Company’s net sales for the years presented. The following table disaggregates revenue for each segment by end market for 2020 and 2019: (Thousands) Performance Alloys and Composites Advanced Materials Precision Optics Other Total 2020 End Market Semiconductor $ 4,626 $ 526,553 $ 456 $ — $ 531,635 Industrial 90,884 38,052 18,096 — 147,032 Aerospace and Defense 67,173 6,241 19,539 — 92,953 Consumer Electronics 47,983 479 21,566 — 70,028 Automotive 66,489 6,262 3,532 — 76,283 Energy 20,587 75,768 — — 96,355 Telecom and Data Center 44,313 2,183 — — 46,496 Other 52,140 15,329 48,023 — 115,492 Total $ 394,195 $ 670,867 $ 111,212 $ — $ 1,176,274 2019 End Market Semiconductor $ 5,353 $ 432,658 $ 711 $ — $ 438,722 Industrial 106,334 29,917 14,253 — 150,504 Aerospace and Defense 109,717 5,647 20,731 — 136,095 Consumer Electronics 72,360 1,254 18,201 — 91,815 Automotive 69,057 8,179 969 — 78,205 Energy 41,101 74,613 — — 115,714 Telecom and Data Center 61,344 2,981 — — 64,325 Other 34,935 18,514 56,595 — 110,044 Total $ 500,201 $ 573,763 $ 111,460 $ — $ 1,185,424

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer	Revenue RecognitionNet sales consist primarily of revenue from the sale of precious and non-precious specialty metals, beryllium and copper-based alloys, beryllium composites, and other products into numerous end markets. The Company requires an agreement with a customer that creates enforceable rights and performance obligations. The Company generally recognizes revenue, in an amount that reflects the consideration to which it expects to be entitled, upon satisfaction of a performance obligation by transferring control over a product to the customer. Control over the product is generally transferred to the customer when the Company has a present right to payment, the customer has legal title, the customer has physical possession, the customer has the significant risks and rewards of ownership, and/or the customer has accepted the product. Shipping and Handling Costs : The Company accounts for shipping and handling activities related to contracts with customers as costs to fulfill its promise to transfer the associated products. Accordingly, customer payments for shipping and handling costs are recorded as a component of net sales, and related costs are recorded as a component of cost of sales. Taxes Collected from Customers and Remitted to Governmental Authorities : Revenue is recorded net of taxes collected from customers that are remitted to governmental authorities, with the collected taxes recorded as current liabilities until remitted to the relevant government authority. Product Warranty : Substantially all of the Company’s customer contracts contain a warranty that provides assurance that the purchased product will function as expected and in accordance with certain specifications. The warranty is intended to safeguard the customer against existing defects and does not provide any incremental service to the customer. Transaction Price Allocated to Future Performance Obligations: ASC 606 requires that the Company disclose the aggregate amount of transaction price that is allocated to performance obligations that have not yet been satisfied at December 31, 2020. Remaining performance obligations include non-cancelable purchase orders and customer contracts. The guidance provides certain practical expedients that limit this requirement. As such, the Company does not disclose the value of unsatisfied performance obligations for contracts with an original expected length of one year or less. After considering the practical expedient, at December 31, 2020, the aggregate amount of the transaction price allocated to remaining performance obligations was approximate ly $10.2 million . Contract Costs : The Company recognizes the incremental costs of obtaining contracts as an expense when incurred if the amortization period of the assets that the Company otherwise would have recognized is one year or less. These costs primarily relate to sales commissions, which are included in selling, general, and administrative expenses. Contract Balances : The timing of revenue recognition, billings, and cash collections resulted in the following contract assets and contract liabilities: (Thousands) December 31, 2020 December 31, 2019 $ change % change Accounts receivable, trade $ 156,821 $ 141,168 $ 15,653 11 % Unbilled receivables 8,832 13,583 (4,751) (35) % Unearned revenue 7,713 3,380 4,333 128 % Accounts receivable, trade represents payments due from customers relating to the transfer of the Company’s products and services. The Company believes that its receivables are collectible and appropriate allowances for doubtful accounts have been recorded. Impairment losses (bad debt) incurred relating to our receivables were immaterial during 2020. Unbilled receivables represent expenditures on contracts, plus applicable profit margin, not yet billed. Unbilled receivables are normally billed and collected within one year. Billings made on contracts are recorded as a reduction of unbilled receivables. Unearned revenue is recorded for consideration received from customers in advance of satisfaction of the related performance obligations. The Company recognized approximately $3.2 million of the December 31, 2019 unearned amounts as revenue during 2020. As a practical expedient, the Company does not adjust the promised amount of consideration for the effects of a significant financing component because the period between the transfer of a product or service to a customer and when the customer pays for that product or service will be one year or less. The Company does not include extended payment terms in its contracts with customers.

Restructuring

Restructuring	12 Months Ended
	Dec. 31, 2020
Restructuring and Related Activities [Abstract]
Restructuring	RestructuringDuring 2020, the Company committed to a plan to sell its Large Area Coatings (LAC) business (a reporting unit within the Precision Optics segment) and determined that it met the criteria to be classified as held for sale. The Company recorded a goodwill impairment charge of $9.1 million in the first quarter of 2020 to write-off the remaining balance of goodwill for the LAC reporting unit. In addition, the Company estimated the fair value of the disposal group as a whole, less costs to sell, and compared the fair value to the remaining carrying value. Based on this review, the Company recorded an additional $1.4 million asset impairment loss. During the third quarter of 2020, the Company concluded that it intended to close its LAC business and, as a result, only a portion of the fixed assets of the LAC business are classified as held for sale. At December 31, 2020, fixed assets totaling $0.2 million were classified as held for sale and reflected within Prepaid and other current assets in the Consolidated Balance Sheet. Costs associated with the closure of the LAC business totaled $1.7 million in 2020 and included $0.7 million of severance associated with approximately 20 employees and $1.0 million of facility and other related costs. Remaining severance payments of $0.6 million and facility costs of $1.0 million related to these initiatives are reflected within Salaries and wages and Other liabilities and accrued items, respectively, in the Consolidated Balance Sheet. The Company expects to incur additional costs related to these initiatives of approximately $0.2 million in the first quarter of 2021. In addition, in 2020, the Company completed additional cost reduction actions in order to align costs with commensurate business levels in its Precision Optics segment. These actions were accomplished through elimination of vacant positions, consolidation of roles, and staff reductions. Costs associated with these actions totaled $0.4 million and included severance associated with approximately 28 employees and other related costs, all of which was paid during 2020. Also, in 2020, the Company initiated a restructuring plan in its PAC segment to close its Warren, Michigan and Fremont, California locations. Costs associated with the plan totaled $8.8 million in 2020 and included $2.1 million of severance associated with approximately 63 employees, and $5.3 million of facility and other related costs. Remaining severance payments of $0.5 million and facility costs of $0.5 million related to these initiatives are reflected within Salaries and wages and Other liabilities and accrued items in the Consolidated Balance Sheet as of December 31, 2020. The Company does not expect to incur any additional costs associated with these initiatives. In 2019, the Company initiated a restructuring plan in its LAC business to reduce headcount, idle certain machinery and equipment, and exit a facility in Windsor, Connecticut. Costs associated with this plan also included severance and related costs for 19 employees, all of which was paid out by the end of 2020. In addition, in 2019, the Company completed cost reduction actions in order to align costs with commensurate business levels. These actions were accomplished through elimination of vacant positions, consolidation of roles, and staff reduction. Costs associated with these actions were in the Other segment and included severance associated with seven employees and other related costs. All severance payments were paid by the end of 2020. Costs associated with cost reduction actions in 2018 were in the Advanced Materials segment and included severance associated with approximately forty employees and other related costs. Remaining severance payments amount to approximately $0.3 million as of December 31, 2020. These costs are presented in the Company's segment results as follows: (Thousands) 2020 2019 2018 Performance Alloys and Composites $ 8,763 $ — $ — Advanced Materials — — 5,599 Precision Optics 2,052 328 — Other 422 457 — Total $ 11,237 $ 785 $ 5,599

Other-net

Other-net	12 Months Ended
	Dec. 31, 2020
Other-net [Abstract]
Other-net	Other-net Other-net is summarized for 2020, 2019, and 2018 as follows: (Income) Expense (Thousands) 2020 2019 2018 Metal consignment fees $ 8,587 $ 9,247 $ 10,999 Amortization of intangible assets 2,377 1,400 2,265 Foreign currency (gain) loss (2,569) 666 1,487 Net loss on disposal of fixed assets 466 344 518 Rental income — (87) (416) Other items (398) 213 481 Total other-net $ 8,463 $ 11,783 $ 15,334

Interest

Interest	12 Months Ended
	Dec. 31, 2020
Interest [Abstract]
Interest	Interest expense-net The following chart summarizes the interest incurred, capitalized, and paid for 2020, 2019, and 2018: (Thousands) 2020 2019 2018 Interest incurred, net $ 3,889 $ 1,641 $ 2,870 Less: Capitalized interest 10 62 399 Total net expense $ 3,879 $ 1,579 $ 2,471 Interest paid $ 3,442 $ 1,799 $ 1,436 The increase in interest expense for 2020 versus 2019 was primarily due to increased borrowings under our revolving credit facility during 2020. The decrease in interest expense in 2019 compared to 2018 was primarily due to interest income earned on investments held in money market accounts. Amortization of deferred financing costs within interest expense was $0.8 million in 2020 and $1.0 million in both 2019 and 2018.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Certain amounts below have been adjusted to reflect the retrospective application of the Company's change in inventory accounting method, as described in Note A. On March 27, 2020, the Coronavirus Aid, Relief and Economic Security (CARES) Act was signed into law. The CARES Act, among other things, includes provisions relating to refundable payroll tax credits, deferment of employer social security payments, net operating loss carryback periods, alternative minimum tax credit refunds, and modifications to the net interest deduction limitations. The Company has examined the impact of the CARES Act on its business and has determined it does not have a material impact to its consolidated financial statements. On July 9, 2020, the U.S. Treasury Department issued final tax regulations related to the foreign-derived intangible income and global intangible low-taxed income (GILTI) provisions. The U.S. Treasury Department also released final tax regulations on July 20, 2020 permitting a taxpayer to elect to exclude from its GILTI inclusion items of income subject to a high effective rate of foreign tax. On December 31, 2020, the U.S. Treasury Department issued final tax regulations for certain employee renumeration in excess of $1 million under IRC Section 162(m). The Company has applied the new legislation to its consolidated financial statements. On December 22, 2017, comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (TCJA) was enacted in the United States. The SEC staff issued Staff Accounting Bulletin No. 118 (SAB 118) to address the application of U.S. GAAP in situations where a registrant did not have the necessary information available, prepared, or analyzed in reasonable detail to complete the accounting for certain income tax effects of the TCJA. The Company applied the guidance in SAB 118 when accounting for the enactment-date effects of the TCJA in 2017 and 2018. The Company completed its accounting for all of the enactment-date income tax effects of the TCJA in the fourth quarter of 2018. During 2018, the Company recognized adjustments to the provisional amounts recorded as of December 31, 2017 and included the adjustments as a component of income tax expense. In 2018, the Company recorded a $11.1 million net tax benefit related to the enactment-date effects of the TCJA, including a $2.8 million tax benefit for the re-measurement of deferred tax assets and liabilities, a $1.2 million tax benefit for the one-time transition tax on the mandatory deemed repatriation of foreign earnings, and a $7.1 million tax benefit related to the generation of foreign tax credits and the reversal of the valuation allowance related to foreign tax credits. Income before income taxes and income tax expense (benefit) are comprised of the following: (Thousands) 2020 2019 2018 Income (loss) before income taxes: Domestic $ (1,153) $ 60,271 $ 20,528 Foreign 9,428 5,265 (3,930) Total income before income taxes $ 8,275 $ 65,536 $ 16,598 Income tax expense: Current income tax expense (benefit): Domestic $ 812 $ 6,995 $ (5,244) Foreign 1,851 1,202 2,710 Total current $ 2,663 $ 8,197 $ (2,534) Deferred income tax (benefit) expense: Domestic $ (5,641) $ 2,687 $ (4,677) Foreign (4,209) 1,258 2,765 Total deferred $ (9,850) $ 3,945 $ (1,912) Total income tax (benefit) expense $ (7,187) $ 12,142 $ (4,446) A reconciliation of the U.S. federal statutory income tax rate to the Company's effective income tax rate is as follows: 2020 2019 2018 U.S. federal statutory rate 21.0 % 21.0 % 21.0 % State and local income taxes, net of federal tax effect (10.0) 1.0 0.2 Effect of excess of percentage depletion over cost depletion (43.0) (4.3) (17.5) Manufacturing production deduction, including impact of NOL carryback — — 6.2 Foreign derived intangible income deduction (1.8) (3.0) (2.8) Non-deductible goodwill impairment 7.1 1.1 — Tax Cuts and Jobs Act impact — 2.3 (66.7) Research and development tax credit (16.4) (1.1) (7.5) Foreign tax credit — (0.3) (1.9) Impact of foreign operations (5.3) 0.9 1.8 Non-deductible transaction costs 6.9 0.2 1.3 Interest from tax authorities (3.8) — — Adjustment to unrecognized tax benefits 1.8 0.2 2.7 Equity compensation (5.3) (3.2) (4.3) Non-deductible officers' compensation 6.8 0.8 — Valuation allowance (45.5) 2.1 38.1 Other items 0.6 0.8 2.6 Effective tax rate (86.9) % 18.5 % (26.8) % Deferred tax assets and (liabilities) are determined based on temporary differences between the financial reporting and tax basis of assets and liabilities. Deferred tax assets and (liabilities) recorded in the Consolidated Balance Sheets consist of the following: December 31, (Thousands) 2020 2019 Asset (liability) Post-employment benefits other than pensions $ 1,564 $ 1,626 Other reserves 226 543 Deferred compensation 3,322 3,314 Environmental reserves 1,301 1,384 Lease liabilities 10,469 4,614 Pensions 7,456 5,149 Accrued compensation expense 2,683 5,364 Net operating loss and credit carryforwards 12,685 13,513 Research and development tax credit carryforward 26 25 Subtotal 39,732 35,532 Valuation allowance (14,134) (17,676) Total deferred tax assets 25,598 17,856 Depreciation (12,112) (10,780) Lease assets (10,261) (4,428) Inventory (3,532) (7,954) Amortization (10,754) (2,426) Mine development (1,669) (3,706) Total deferred tax liabilities (38,328) (29,294) Net deferred tax liabilities $ (12,730) $ (11,438) The Company had deferred income tax assets offset with a valuation allowance for certain foreign and state net operating losses, state investment and research and development tax credit carryforwards, and deferred tax assets that are not likely to be realized for several of the Company's controlled foreign corporations. The Company intends to maintain a valuation allowance on these deferred tax assets until a realization event occurs to support reversal of all or a portion of the allowance. At December 31, 2020, for income tax purposes, the Company had foreign net operating loss carryforwards of $27.8 million that do not expire, and $7.1 million that expire in calendar years 2021 through 2027. The Company also had state net operating loss carryforwards of $20.5 million that expire in calendar years 2021 through 2040 and state tax credits of $3.7 million that expire in calendar years 2021 through 2035. A valuation allowance of $9.5 million has been provided against certain foreign and state net operating loss carryforwards and state tax credits due to uncertainty of their realization. The Company files income tax returns in the U.S. federal jurisdiction, and in various state, local, and foreign jurisdictions. With limited exceptions, the Company is no longer subject to U.S. federal examinations for years before 2015, state and local examinations for years before 2016, and foreign examinations for tax years before 2011. We operate under a tax holiday in Malaysia, which is effective through July 31, 2022, and may be extended if certain additional requirements are satisfied. The tax holiday is conditional upon our meeting certain employment, sales, and investment thresholds. The impact of this holiday decreased foreign taxes by $0.5 million in 2020. The benefit of the tax holiday on net income per share (diluted) was $0.03 in 2020. A reconciliation of the Company’s unrecognized tax benefits (excluding interest and penalties) for the year-to-date periods ended December 31, 2020 and 2019 is as follows: (Thousands) 2020 2019 Balance at January 1 $ 3,221 $ 2,883 Additions to tax provisions related to the current year 191 — Additions to tax positions related to prior years — 399 Reduction to tax positions related to prior years (349) — Lapses on statutes of limitations (703) (61) Balance at December 31 $ 2,360 $ 3,221 Included in the balance as of December 31, 2020 and December 31, 2019 are $2.7 million and $2.4 million, respectively, of unrecognized tax benefits that would impact the Company’s effective tax rate if recognized. We believe it is reasonably possible that a decrease of up to $1.6 million of unrecognized tax benefits related to federal exposures may be recognized in the next twelve months as a result of the lapse of the statute of limitations. The Company recognizes interest and penalties related to unrecognized tax benefits on the income tax expense line in the accompanying Consolidated Statements of Income. Accrued interest and penalties are included on the related tax liability line in the Consolidated Balance Sheets. The amount of interest and penalties, net of the related tax benefit, recognized in earnings was immaterial during 2020, 2019, and 2018. As of December 31, 2020 and 2019, accrued interest and penalties, net of the related tax benefit, were immaterial. Income taxes paid during 2020, 2019, and 2018, were approximately $3.9 million, $9.3 million, and $2.6 million, respectively.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table sets forth the computation of basic and diluted EPS: (Thousands except per share amounts) 2020 2019* 2018* Numerator for basic and diluted EPS: Net income $ 15,462 $ 53,394 $ 21,044 Denominator: Denominator for basic EPS: Weighted-average shares outstanding 20,338 20,365 20,212 Effect of dilutive securities: Stock appreciation rights 39 72 170 Restricted stock units 102 75 85 Performance-based restricted stock units 124 143 146 Diluted potential common shares 265 290 401 Denominator for diluted EPS: Adjusted weighted-average shares outstanding 20,603 20,655 20,613 Basic EPS $ 0.76 $ 2.62 $ 1.04 Diluted EPS $ 0.75 $ 2.59 $ 1.02 * Amounts for the years ended December 31, 2019 and 2018 have been adjusted to reflect the change in inventory accounting method, as described in Note A . Equity awards covering shares of common stock totaling 166,255 in 2020, 71,199 in 2019, and 65,122 in 2018 were excluded from the diluted EPS calculation as their effect would have been anti-dilutive.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2020
Inventory Disclosure [Abstract]
Inventories	Inventories, net Inventories are stated at the lower of cost or net realizable value. In the fourth quarter of 2020, the Company voluntarily changed its method of inventory costing for the majority of its domestic inventories to the FIFO method from the LIFO method. The Company believes that the FIFO method is preferable as it results in uniformity across the Company's global operations, provides better matching of revenues and expenses, and improves comparability with the Company's peers. Inventories in the Consolidated Balance Sheets are summarized as follows: December 31, (Thousands) 2020 2019* Raw materials and supplies $ 42,905 $ 35,612 Work in process 200,741 175,135 Finished goods 7,132 25,506 Inventories, net 250,778 236,253 * December 31, 2019 amounts have been adjusted to reflect the change in inventory accounting method, as described in Note A. The Company takes and records the results of a physical inventory count of its precious metals on a quarterly basis. The Company's precious metal operations include a refinery that processes precious metal-containing scrap and other materials from its customers, as well as its own internally generated scrap. The Company also outsources portions of its refining requirements to other vendors, particularly those materials with longer processing times. The precious metal content within these various refine streams may be in solutions, sludges, and other non-homogeneous forms and can vary over time based upon the input materials, yield rates, and other process parameters. The determination of the weight of the precious metal content within the refine streams as part of a physical inventory count requires the use of estimates and calculations based upon assays, assumed recovery percentages developed from actual historical data and other analyses, the total estimated volumes of solutions and other materials within the refinery, data from the Company's refine vendors, and other factors. The resulting calculated weight of the precious metals in the Company's refine operations may differ, in either direction, from what its records indicate that the Company should have on hand, which would then result in an adjustment to its pre-tax income in the period when the physical inventory was taken, and the related estimates were made.

Property, Plant, and Equipment

Property, Plant, and Equipment	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Property, Plant, and Equipment	Property, Plant, and Equipment Property, plant, and equipment on the Consolidated Balance Sheets is summarized as follows: December 31, (Thousands) 2020 2019 Land $ 5,686 $ 4,874 Buildings 165,144 150,323 Machinery and equipment 645,195 639,310 Software 43,652 44,652 Construction in progress 69,297 16,699 Allowances for depreciation (662,724) (669,250) Subtotal 266,250 186,608 Finance leases 34,301 26,069 Allowances for depreciation (4,914) (3,569) Subtotal 29,387 22,500 Mineral resources 4,979 4,980 Mine development 30,058 30,058 Allowances for amortization and depletion (20,988) (11,870) Subtotal 14,049 23,168 Property, plant, and equipment — net $ 309,686 $ 232,276 The Company received $63.5 million from the U.S. Department of Defense (DoD), in previous periods, for reimbursement of the DoD's share of the cost of equipment. This amount was recorded in property, plant, and equipment and the reimbursements are reflected in Unearned income on the Consolidated Balance Sheets. The equipment was placed in service during 2012, and its full cost is being depreciated in accordance with Company policy. The unearned income liability is being reduced ratably with the depreciation expense recorded over the life of the equipment. Unearned income was reduced b y $4.3 million in both 2020 and 2018 a nd $4.4 million in 2019 and credited to cost of sales in the Consolidated Statements of Income, offsetting the impact of the depreciation expense on the associated equipment on the Company's cost of sales and gross margin. We recorded depreciation and depletion expense o f $30.9 million i n 2020, $30.3 million in 2019, and $33.3 million in 2018. Depreciation, depletion, and amortization as shown on the Consolidated Statement of Cash Flows is also net of the reduction in the unearned income liability in 2020, 2019, and 2018. The net carrying value of capitalized so ftware w as $5.0 million and $7.9 million at December 31, 2020 and December 31, 2019, respectively. Depreciation expense related to software was $1.8 million, $2.4 million, and $2.6 million in 2020, 2019, and 2018, respectively.

Customer Prepayments

Customer Prepayments	12 Months Ended
	Dec. 31, 2020
Revenue Recognition and Deferred Revenue [Abstract]
Customer Prepayments	Customer Prepayments The Company entered into investment and master supply agreements with a customer to procure equipment to manufacture product for the customer. The customer will make prepayments to the Company in the amount of approximately $70 million in the aggregate to enable the Company to purchase and install certain equipment and make necessary infrastructure improvements to supply product to the customer. The Company will own the equipment and be responsible for operating and maintenance costs. The prepayment from the customer will be applied when commercial production of the product is sold and delivered to the customer in connection with a master supply agreement. Accordingly, as of December 31, 202 0, $58.8 million of prepayments are classified as Unearned income in the Consolidated Balance Sheet and the liabilities are expected to be settled as commercial shipments are made.

Leasing Arrangements

Leasing Arrangements	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leasing Arrangements	Leasing Arrangements The Company leases warehouse and manufacturing real estate, and manufacturing and computer equipment under operating leases with lease terms ranging up to 25 years. Several operating lease agreements contain options to extend the lease term and/or options for early termination. The lease term consists of the non-cancelable period of the lease, periods covered by options to extend the lease if the Company is reasonably certain to exercise the option, and periods covered by an option to terminate the lease if the Company is reasonably certain not to exercise the option. As of December 31, 2020, we had no material leases that had yet to commence. The discount rate implicit within the leases is generally not determinable, and, therefore, the Company determines the discount rate based on its incremental borrowing rate. The incremental borrowing rate for leases is determined based on the lease term in which lease payments are made, adjusted for impacts of collateral. The components of operating and finance lease cost for 2020 and 2019 were as follows: (Thousands) 2020 2019 Components of lease expense Operating lease cost $ 10,602 $ 9,835 Finance lease cost Amortization of right-of-use assets 1,324 1,414 Interest on lease liabilities 1,021 1,028 Total lease cost $ 12,947 $ 12,277 Operating lease expense under ASC 840 amounted to $11.6 million during 2018. The Company straight-lines its expense of fixed payments for operating leases over the lease term and expenses the variable lease payments in the period incurred. These variable lease payments are not included in the calculation of right-of-use assets or lease liabilities. Supplemental balance sheet information related to the Company's operating and finance leases as of December 31, 2020 and 2019 was as follows: (Thousands, except lease term and discount rate) 2020 2019 Supplemental balance sheet information Operating Leases Operating lease right-of-use assets $ 62,089 $ 23,413 Other liabilities and accrued items 6,908 6,542 Operating lease liabilities 56,761 18,091 Finance Leases Property, plant, and equipment $ 34,301 $ 26,069 Allowances for depreciation, depletion, and amortization (4,914) (3,570) Finance lease assets, net $ 29,387 $ 22,499 Other liabilities and accrued items $ 2,925 $ 1,265 Finance lease liabilities 20,539 17,424 Total principal payable on finance leases $ 23,464 $ 18,689 Weighted Average Remaining Lease Term Operating leases 12.72 4.69 Finance leases 16.59 19.47 Weighted Average Discount Rate Operating leases 6.46% 5.91% Finance leases 4.88% 5.31% Future maturities of the Company's lease liabilities as of December 31, 2020 are as follows: Finance Operating (Thousands) Leases Leases 2021 $ 3,877 $ 10,707 2022 3,827 9,415 2023 2,536 8,750 2024 1,595 6,608 2025 1,432 6,278 2026 and thereafter 21,906 53,041 Total lease payments 35,173 94,799 Less amount of lease payment representing interest 11,709 31,130 Total present value of lease payments $ 23,464 $ 63,669 Supplemental cash flow information related to leases was as follows: (Thousands) 2020 2019 Supplemental cash flow information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 16,216 $ 15,841 Operating cash flows from finance leases 1,021 1,028 Financing cash flows from finance leases 2,213 1,200 Right-of-use assets obtained in exchange for lease obligations: Operating leases 43,037 32,534 Finance leases 6,736 3,919

Intangible Assets and Goodwill

Intangible Assets and Goodwill	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	Intangible Assets and Goodwill Intangible Assets The cost and accumulated amortization of intangible assets subject to amortization as of December 31, 2020 and 2019, is as follows: 2020 2019 (Thousands) Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net Customer relationships $ 81,231 $ (38,773) $ 42,458 $ 39,601 $ (37,692) $ 1,909 Technology 16,915 (13,290) 3,625 13,377 (12,816) 561 Licenses and other 11,457 (4,840) 6,617 4,257 (3,046) 1,211 Total $ 109,603 $ (56,903) $ 52,700 $ 57,235 $ (53,554) $ 3,681 During 2020, the Company acquired $40.1 million in customer relationships with a useful life of eighteen years, as well as $4.1 million in technology and $5.1 million in other intangible assets, both of which have a five years useful life. Amortization expense for 2020, 2019, and 2018 was $2.4 million, $1.4 million, and $2.3 million, respectively. Estimated amortization e xpense for each of the five succeeding years is as follows: Amortization (Thousands) Expense 2021 4,596 2022 4,585 2023 4,565 2024 4,563 2025 4,084 Intangible assets also includes deferred financing costs relating to the Company's revolving credit and consignments lines of $2.0 million and $2.7 million at December 31, 2020 and 2019, respectively. Goodwill In 2020, the Company acquired Optics Balzers for a total purchase price of $136.1 million, including the assumption of debt, and recorded goodwill of $70.6 million. Optics Balzers is included in the Precision Optics segment. The balance of goodwill at December 31, 2020 and 2019 was $144.9 million and $79.0 million, respectively. A summary of changes in goodwill by reportable segment is as follows: (Thousands) Performance Alloys and Composites Advanced Materials Precision Optics Total Balance at December 31, 2018 $ 1,899 $ 50,276 $ 38,482 $ 90,657 Impairment charge — — (11,560) (11,560) Other — (86) — (86) Balance at December 31, 2019 $ 1,899 $ 50,190 $ 26,922 $ 79,011 Acquisition — — 70,577 70,577 Impairment charge — — (9,053) (9,053) Other — 337 4,044 4,381 Balance at December 31, 2020 $ 1,899 50,527 $ 92,490 $ 144,916 In 2020, the Company recorded a $9.1 million goodwill impairment charge to write-off the remaining balance of goodwill for the LAC reporting unit which was closed as of December 31, 2020. See Note E for additional details of the restructuring plan. During the third quarter of 2019, the LAC reporting unit began to experience a decline in sales volume from a significant customer. Based on an assessment that the decline in sales volume was expected to continue, the Company initiated a restructuring plan at the end of the third quarter to reduce the LAC reporting unit’s cost structure. Refer to Note E for further details of the restructuring plan. The Company considered these factors to be impairment indicators. As a result, the Company performed an interim impairment analysis as of September 27, 2019 using a "step one" quantitative assessment for the LAC reporting unit. The LAC reporting unit prepared an operating forecast that included several assumptions including future sales growth from new products and applications, as well as assumptions regarding future industry-specific market conditions, capital expenditures, and working capital changes. In addition to the estimates of future cash flows, other significant estimates involved in the determination of fair value of the reporting unit were the weighted average cost of capital (discount rate), annual growth rate, and terminal growth rate used in the discounted cash flow (DCF) model. The discount rates used in the DCF model consider market and industry data as well as specific risk premiums for the LAC reporting unit. The Company first reviewed long-lived assets, which resulted in an impairment charge of $2.6 million in the third quarter of 2019. The Company then performed a goodwill impairment analysis which resulted in an $11.6 million charge in the third quarter of 2019, which represents the excess of the carrying value over the estimated fair value of LAC. The Company estimated fair value using a discounted cash flow analysis for goodwill and estimated market values for other assets. These non-cash charges relating to goodwill and other assets were recorded in Goodwill impairment charges and Asset impairment charges, respectively, in the Consolidated Statements of Income. The results of the Company's 2020, 2019, and 2018 annual goodwill impairment assessments indicated that no other goodwill impairment existed. Accumulated impairment losses were $20.6 million and $11.6 million at December 31, 2020 and 2019, respectively, all of which related to the LAC reporting unit.

Debt

Debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt	Debt Long-term debt in the Consolidated Balance Sheets is summarized as follows: December 31, (Thousands) 2020 2019 Borrowings under Credit Agreement with average interest rate of 1.65% at December 31, 2020 $ 34,000 $ — Foreign debt 3,157 — Fixed rate industrial development revenue bonds 1,322 2,218 Total long-term debt outstanding 38,479 2,218 Current portion of long-term debt (1,937) (868) Gross long-term debt 36,542 1,350 Unamortized deferred financing fees — (90) Long-term debt $ 36,542 $ 1,260 Maturities on long-term debt instruments as of December 31, 2020 are as follows: (Thousands) 2021 $ 1,937 2022 500 2023 387 2024 34,387 2025 387 2026 and thereafter 881 Total $ 38,479 In September 2019, the Company amended and restated the agreement governing its $375.0 million revolving credit facility (Credit Agreement). The maturity date of the Credit Agreement was extended from 2020 to 2024, and the Credit Agreement provides more favorable interest rates under certain circumstances. In addition, the Credit Agreement provides the Company and its subsidiaries with additional capacity to enter into facilities for the consignment, borrowing, or leasing of precious metals and copper, and provides enhanced flexibility to finance acquisitions and other strategic initiatives. The Credit Agreement also provides for an uncommitted incremental facility whereby, under certain conditions, the Company may be able to borrow additional term loans in an aggregate amount not to exceed $200.0 million. Borrowings under the Credit Agreement are secured by substantially all of the assets of the Company and its direct subsidiaries, with the exception of non-mining real property and certain other assets. The Credit Agreement allows the Company to borrow money at a premium over LIBOR or prime rate and at varying maturities. The premium resets quarterly according to the terms and conditions available under the Credit Agreement. The Company borrowed $150.0 million under the Credit Agreement during 2020 as a precaution in light of the COVID-19 pandemic. A portion of the amount borrowed was used to fund the Optics Balzers acquisition. At December 31, 2020, there was $34.0 million outstanding under this Credit Agreement. No amounts were outstanding at December 31, 2019. The Credit Agreement includes restrictive covenants relating to restrictions on additional indebtedness, acquisitions, dividends, and stock repurchases. In addition, the Credit Agreement includes covenants subject to a maximum leverage ratio and a minimum fixed charge coverage ratio. The Company was in compliance with all of its debt covenants as of December 31, 2020 and December 31, 2019. At December 31, 2020 and 2019 there was $48.1 million and $41.8 million outstanding against the letters of credit sub-facility, respectively. The Company pays a variable commitment fee that may reset quarterly (0.2% as of December 31, 2020) of the available and unborrowed amounts under the revolving credit line. The available borrowings under the individual existing credit lines total $245.8 million as of December 31, 2020.

Pensions and Other Post-Employm

Pensions and Other Post-Employment Benefits	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Pensions and Other Post-Employment Benefits	Pensions and Other Post-Employment Benefits The obligation and funded status of the Company’s pension and other post-employment benefit plans are shown below. The Pension Benefits column aggregates defined benefit pension plans in the U.S., Germany, Liechtenstein, and England, and the U.S. supplemental retirement plans. The Other Benefits column includes the domestic retiree medical and life insurance plan. Pension Benefits Other Benefits (Thousands) 2020 2019 2020 2019 Change in benefit obligation Benefit obligation at beginning of year $ 186,760 $ 170,136 $ 8,681 $ 11,375 Service cost 1,403 5,918 59 67 Interest cost 5,234 6,292 213 399 Net pension curtailments and settlements (609) (12,212) — — Acquisition 30,360 — — — Plan amendments (799) — — — Actuarial loss (gain) 24,259 20,409 224 (2,192) Benefit payments (4,612) (3,170) (989) (981) Foreign currency exchange rate changes and other 4,111 (613) 2 13 Benefit obligation at end of year 246,107 186,760 8,190 8,681 Change in plan assets Fair value of plan assets at beginning of year 174,046 145,046 — — Plan settlements — — — — Acquisition 23,774 — — — Actual return on plan assets 30,330 27,264 — — Employer contributions 614 4,702 — — Employee contributions 498 124 — — Benefit payments from fund (4,720) (2,933) — — Expenses paid from assets (234) (391) — — Foreign currency exchange rate changes and other 1,868 234 — — Fair value of plan assets at end of year 226,176 174,046 — — Funded status at end of year $ (19,931) $ (12,714) $ (8,190) $ (8,681) Amounts recognized in the Consolidated Other assets $ 13,074 $ 11,298 $ — $ — Other liabilities and accrued items (470) (997) (866) (1,012) Retirement and post-employment benefits (32,535) (23,015) (7,324) (7,669) Net amount recognized $ (19,931) $ (12,714) $ (8,190) $ (8,681) The benefit obligation increased in 2020 primarily due to the Optics Balzers acquisition, as well as actuarial losses that were driven by decreases in the discount rate as well as participant census data updates. In 2019, the Company's Board of Directors approved changes to the U.S. defined benefit pension plan. The Company froze the pay and service amounts used to calculate the pension benefits for active participants as of January 1, 2020. The Company recognized a non-cash pretax pension curtailment charge of $3.3 million associated with the plan amendment in 2019. The following amounts are included within accumulated other comprehensive loss at December 31, 2020: Pension Benefits Other Benefits (Thousands) 2020 2019 2020 2019 Amounts recognized in other comprehensive income (before tax) consist of: Net actuarial loss (gain) $ 49,472 $ 48,073 $ (3,973) $ (4,529) Net prior service cost (credit) (799) — (3,552) (5,049) Net amount recognized $ 48,673 $ 48,073 $ (7,525) $ (9,578) The following table provides information regarding the accumulated benefit obligation: Pension Benefits Other Benefits (Thousands) 2020 2019 2020 2019 Additional information Accumulated benefit obligation for all defined benefit pension plans $ 243,953 $ 185,402 $ — $ — For defined benefit pension plans with benefit obligations in excess of plan assets: Aggregate benefit obligation 62,012 25,640 — — Aggregate fair value of plan assets 29,938 3,045 — — For defined benefit pension plans with accumulated benefit obligations in excess of plan assets: Aggregate accumulated benefit obligation 59,858 24,482 — — Aggregate fair value of plan assets 29,938 3,045 — — The following table summarizes components of net benefit cost: Pension Benefits Other Benefits (Thousands) 2020 2019 2018 2020 2019 2018 Net benefit cost Service cost $ 1,403 $ 5,918 $ 6,953 $ 59 $ 67 $ 111 Interest cost 5,234 6,292 9,554 213 399 396 Expected return on plan assets (9,333) (8,777) (14,231) — — — Amortization of prior service credit — 483 (123) (1,497) (1,497) (1,497) Recognized net actuarial loss (gain) 1,678 3,304 7,171 (332) (93) — Net periodic benefit (credit) cost (1,018) 7,220 9,324 (1,557) (1,124) (990) Net pension curtailments and settlements 94 3,328 41,406 — — — Total net benefit (credit) cost $ (924) $ 10,548 $ 50,730 $ (1,557) $ (1,124) $ (990) In 2019, net benefit cost includes a $3.3 million curtailment charge related to the freeze of our U.S. defined benefit plan effective January 1, 2020. Net benefit cost for 2018 includes settlement charges of $41.4 million primarily related to the remeasurement of the periodic benefit obligation of the U.S. plans in conjunction with the purchase of a group annuity contract from Mutual of America. Components of net periodic benefit cost, other than service cost, are included in Other non-operating (income) expense in the Consolidated Statements of Income. Additionally, Pension Benefit Guaranty Corporation premiums are reported within expected return on plan assets. The following table summarizes amounts recognized in other comprehensive income (OCI): Pension Benefits Other Benefits (Thousands) 2020 2019 2018 2020 2019 2018 Change in other comprehensive income OCI at beginning of year $ 48,073 $ 65,409 $ 122,802 $ (9,578) $ (8,976) $ (8,020) Increase (decrease) in OCI: Recognized during year — prior service cost (credit) — (3,811) 123 1,497 1,497 1,497 Recognized during year — net actuarial (losses) gains (1,678) (3,304) (7,171) 332 93 — Occurring during year — prior service cost (799) — — — — — Occurring during year — net actuarial losses (gains) 3,146 2,062 (8,997) 224 (2,192) (2,453) Other adjustments (94) (12,212) (41,406) — — — Foreign currency exchange rate changes 25 (71) 58 — — — OCI at end of year $ 48,673 $ 48,073 $ 65,409 $ (7,525) $ (9,578) $ (8,976) In determining the projected benefit obligation and the net benefit cost, as of a December 31 measurement date, the Company used the following weighted-average assumptions: Pension Benefits Other Benefits 2020 2019 2018 2020 2019 2018 Weighted-average assumptions used to determine benefit obligations at fiscal year end Discount rate 2.14 % 3.12 % 4.07 % 2.45 % 3.20 % 4.11 % Rate of compensation increase 2.22 % 3.00 % 3.87 % 3.00 % 3.00 % 4.00 % Weighted-average assumptions used to determine net cost for the fiscal year Discount rate 8.37 % 4.16 % 3.63 % 3.20 % 4.11 % 3.43 % Expected long-term return on plan assets 5.70 % 6.06 % 6.63 % N/A N/A N/A Rate of compensation increase 2.87 % 2.99 % 3.98 % 3.00 % 4.00 % 4.00 % Discount Rate. The discount rate used to determine the present value of the projected and accumulated benefit obligation at the end of each year is established based upon the available market rates for high quality, fixed income investments whose maturities match the plan’s projected cash flows. The Company uses a spot-rate approach to estimate the service and interest cost components of net periodic benefit cost for its defined benefit pension plans. The spot-rate approach applies separate discount rates for each projected benefit payment in the calculation. Expected Long-Term Return on Plan Assets. Management establishes the domestic expected long-term rate of return assumption by reviewing historical trends and analyzing the current and projected market conditions in relation to the plan’s asset allocation and risk management objectives. Consideration is given to both recent plan asset performance as well as plan asset performance over various long-term periods of time, with an emphasis on the assumption being a prospective, long-term rate of return. Management consults with and considers the opinions of its outside investment advisers and actuaries when establishing the rate and reviews assumptions with the Audit Committee of the Board of Directors. Rate of Compensation Increase. The rate of compensation increase assumption was not applicable for the domestic defined benefit plan in 2019 due to the Company freezing the plan effective January 1, 2020. The rate of compensation assumption for the domestic retiree medical plan was 3.0% in 2020 and 4.0% in 2019 for both the domestic defined benefit pension plan and the domestic retiree medical plan. Assumptions for the defined benefit pension plans in Germany, Liechtenstein, and England are determined separately from the U.S. plan assumptions, based on historical trends and current and projected market conditions in each respective country. One plan in Germany is unfunded. Assumed health care trend rates at fiscal year end 2020 2019 Health care trend rate assumed for next year 6.00% 6.25% Rate that the trend rate gradually declines to (ultimate trend rate) 5.00% 5.00% Year that the rate reaches the ultimate trend rate 2025 2025 Plan Assets The following tables present the fair values of the Company’s defined benefit pension plan assets as of December 31, 2020 and 2019 by asset category. The Company has some investments that are valued using net asset value (NAV) as the practical expedient and have not been classified in the fair value hierarchy. Refer to Note S for definitions of the fair value hierarchy. December 31, 2020 (Thousands) Total Level 1 Level 2 Level 3 Cash $ 2,204 $ 2,204 $ — $ — Equity securities (a) 49,293 49,293 — — Fixed-income securities (b) 20,375 20,375 — — Other types of investments: Real estate fund (c) 6,105 6,105 — — Total 77,977 77,977 — — Investments measured at NAV: (d) Pooled investment fund (e) 143,503 Multi-strategy hedge funds (f) 4,624 Private equity funds 72 Total assets at fair value $ 226,176 December 31, 2019 (Thousands) Total Level 1 Level 2 Level 3 Cash $ 1,718 $ 1,718 $ — $ — Equity securities (a) 47,722 47,722 — — Fixed-income securities (b) 3,923 3,923 — — Other types of investments: Real estate fund (c) 3,121 3,121 — — Total 56,484 56,484 — — Investments measured at NAV: (d) Pooled investment fund (e) 113,187 Multi-strategy hedge funds (f) 4,277 Private equity funds 98 Total assets at fair value $ 174,046 (a) Equity securities are primarily comprised of corporate stock and mutual funds directly held by the plans. Equity securities are valued using the closing price reported on the active market on which the individual securities are traded. (b) Fixed income securities are primarily comprised of governmental and corporate bonds directly held by the plans. Governmental and corporate bonds are valued using both market observable inputs for similar assets that are traded on an active market and the closing price on the active market on which the individual securities are traded. (c) Includes a mutual fund that typically invests at least 80% of its assets in equity and debt securities of companies in the real estate industry or related industries or in companies which own significant real estate assets at the time of investment. (d) Certain assets that are measured at fair value using the NAV practical expedient have not been classified in the fair value hierarchy. (e) Pooled investment fund consists of various investment types including equity investments covering a range of geographies and including investment managers that hold long and short positions, property investments, and other multi-strategy funds which combine a range of different credit, equity, and macro-orientated ideas and dynamically allocate funds across asset classes. (f) Includes a fund that invests in a broad portfolio of hedge funds. The Company’s domestic defined benefit pension plan investment strategy, as approved by the Governance and Organization Committee of the Board of Directors, is to employ an allocation of investments that will generate returns equal to or better than the projected long-term growth of pension liabilities so that the plan will be self-funding. The return objective is to maximize investment return to achieve and maintain a 100% funded status over time, taking into consideration required cash contributions. The allocation of investments is designed to maximize the advantages of diversification while mitigating the risk and overall portfolio volatility to achieve the return objective. Risk is defined as the annual variability in value and is measured in terms of the standard deviation of investment return. Under the Company’s investment policies, allowable investments include domestic equities, international equities, fixed income securities, cash equivalents, and alternative securities (which include real estate, private venture capital investments, hedge funds, and tactical asset allocation). Ranges, in terms of a percentage of the total assets, are established for each allowable class of security. Derivatives may be used to hedge an existing security or as a risk reduction strategy. Current asset allocation guidelines are to invest 10% to 40% in equity securities, 60% to 90% in fixed income securities and cash, and up to 20% in alternative securities. Management reviews the asset allocation on a quarterly or more frequent basis and makes revisions as deemed necessary. None of the plan assets noted above are invested in the Company’s common stock. Cash Flows Employer Contributions. The Company does not expect to contribute to its domestic defined benefit pension plan in 2021. All plan participants with an accrued benefit may elect an immediate payout in lieu of their future monthly annuity if the lump sum amount does not exceed $100,000. Estimated Future Benefit Payments. The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid: Other Benefits (Thousands) Pension Benefits Gross Benefit Net of 2021 4,987 867 853 2022 5,854 812 800 2023 7,401 746 736 2024 8,689 667 659 2025 8,924 603 596 2026 through 2030 54,116 2,140 2,120 Other Benefit Plans In addition to the plans shown above, the Company also has certain foreign subsidiaries with accrued unfunded pension and other post-employment arrangements. The liability for these arrangements was $1.7 million at December 31, 2020 and $1.4 million at December 31, 2019, and was included in retirement and post-employment benefits in the Consolidated Balance Sheets.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Accumulated Other Comprehensive Income	Accumulated Other Comprehensive (Loss) Income Changes in the components of accumulated other comprehensive (loss) income, including amounts reclassified out, for 2020, 2019, and 2018, and the balances in accumulated other comprehensive (loss) income as of December 31, 2020, 2019, and 2018 are as follows: Gains and Losses Pension and Post- Employment Benefits Foreign Currency Translation (Thousands) Foreign Currency Precious Metals Copper Total Total Balance at December 31, 2017 $ 959 $ (196) $ — $ 763 $ (99,592) $ (4,108) $ (102,937) Other comprehensive income (loss) before reclassifications (333) 467 (569) (435) 11,396 (484) 10,477 Amounts reclassified from accumulated other comprehensive income 10 (109) — (99) 46,953 — 46,854 Other comprehensive income (loss) before tax (323) 358 (569) (534) 58,349 (484) 57,331 Deferred taxes on current period activity (627) 83 (128) (672) 13,300 — 12,628 Other comprehensive income (loss) after tax 304 275 (441) 138 45,049 (484) 44,703 Balance at December 31, 2018 $ 1,263 $ 79 $ (441) $ 901 $ (54,543) $ (4,592) $ (58,234) Balance at December 31, 2018 $ 1,263 $ 79 $ (441) $ 901 $ (54,543) $ (4,592) $ (58,234) Other comprehensive income (loss) before reclassifications 108 (1,285) 209 (968) 9,085 (421) 7,696 Amounts reclassified from accumulated other comprehensive income (29) 595 393 959 8,853 — 9,812 Other comprehensive income (loss) before tax 79 (690) 602 (9) 17,938 (421) 17,508 Deferred taxes on current period activity 18 (159) 136 (5) 4,741 — 4,736 Other comprehensive income (loss) after tax 61 (531) 466 (4) 13,197 (421) 12,772 Balance at December 31, 2019 $ 1,324 $ (452) $ 25 $ 897 $ (41,346) $ (5,013) $ (45,462) Balance at December 31, 2019 $ 1,324 $ (452) $ 25 $ 897 $ (41,346) $ (5,013) $ (45,462) Other comprehensive income (loss) before reclassifications (1,268) (1,675) 218 (2,725) (2,721) 9,030 3,584 Amounts reclassified from accumulated other comprehensive income 222 2,041 354 2,617 (57) — 2,560 Other comprehensive income (loss) before tax (1,046) 366 572 (108) (2,778) 9,030 6,144 Deferred taxes on current period activity (241) 84 129 (28) (651) — (679) Other comprehensive income (loss) after tax (805) 282 443 (80) (2,127) 9,030 6,823 Balance at December 31, 2020 $ 519 $ (170) $ 468 $ 817 $ (43,473) $ 4,017 $ (38,639) Reclassifications from accumulated other comprehensive income of gains and losses on foreign currency cash flow hedges are recorded in Net sales in the Consolidated Statements of Income while gains and losses on precious metal cash flow hedges are recorded in Cost of sales in the Consolidated Statements of Income. Refer to Note S for additional details on cash flow hedges.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock-based Compensation	Stock-based Compensation Stock incentive plans (the 2006 Stock Incentive Plan and the 2006 Non-employee Director Equity Plan) were approved at the May 2006 annual meeting of shareholders. These plans authorize the granting of option rights, stock appreciation rights (SARs), performance-restricted shares, performance shares, performance units, restricted shares, and restricted stock units (RSUs). The 2006 Stock Incentive Plan and the 2006 Non-employee Director Equity Plan were amended to, among other things, add additional shares to the plans. These amendments were last approved by shareholders at the May 2017 annual meeting. Stock-based compensation expense, which includes awards settled in shares and in cash and is recognized as a component of selling, general, and administrative (SG&A) expenses, was $5.7 million, $11.1 million, and $11.4 million in 2020, 2019, and 2018, respectively. The Company derives a tax deduction measured by the excess of the market value over the grant price at the date stock-based awards vest or are exercised. The Company recognized $0.5 million, $2.1 million, and $1.2 million of tax benefits in 2020, 2019, and 2018, respectively, relating to the issuance of common stock for the exercise/vesting of equity awards. The following sections provide information on awards settled in shares. SARs. The Company grants SARs to certain employees. Upon exercise of vested SARs, the participant will receive a number of shares of common stock equal to the spread (the difference between the market price of the Company’s common shares at the time of exercise and the strike price established on the grant date) divided by the common share price. The strike price of the SARs is equal to the market value of the Company’s common shares on the day of the grant. The number of SARs available to be issued is established by plans approved by the shareholders. The vesting period and the life of the SARs are established at the time of grant. The exercise of the SARs is generally satisfied by the issuance of treasury shares. SARs vest in equal installments annually over three years. SARs expire in seven years. The following table summarizes the Company's SARs activity during 2020: (Shares in thousands) Number of Weighted- Aggregate Weighted- Outstanding at December 31, 2019 250 $ 44.95 Granted 65 50.95 Exercised (29) 40.70 Cancelled (32) 51.43 Outstanding at December 31, 2020 254 46.18 $ 4,454 4.2 Vested and expected to vest as of December 31, 2020 254 46.18 4,454 4.2 Exercisable at December 31, 2020 148 41.00 3,368 3.4 A summary of the status and changes of shares subject to SARs and the related average price per share follows: (Shares in thousands) Number of Weighted- Nonvested as of December 31, 2019 178 $ 14.72 Granted 65 13.67 Vested (109) 13.21 Cancelled (28) 15.50 Nonvested as of December 31, 2020 106 $ 15.46 As of December 31, 2020, $0.9 million of expense with respect to non-vested SARs has yet to be recognized as expense over a weighted-average period of approximately 20 months. The total fair value of shares vested during 2020 was $1.5 million, compared to $1.9 million in both 2019 and 2018. The weighted-average grant date fair value for 2020, 2019, and 2018 was $13.67, $17.76, and $15.73, respectively. The fair value will be amortized to compensation cost on a straight-line basis over the vesting period of three years, or earlier if the employee is retirement eligible as defined in the Plan. Stock-based compensation expense relating to SARs was $0.9 million in both 2020 and 2019 and $0.7 million in 2018. The fair value of the SARs was estimated on the grant date using the Black-Scholes pricing model with the following assumptions: 2020 2019 2018 Risk-free interest rate 1.41 % 2.47 % 2.58 % Dividend yield 0.9 % 0.7 % 0.8 % Volatility 31.8 % 31.7 % 31.9 % Expected lives (in years) 4.8 5.2 5.5 The risk-free rate of return was based on U.S. Treasury yields with a maturity equal to the expected life of the award. The dividend yield was based on the Company's historical dividend rate and stock price. The expected volatility of stock was derived by referring to changes in the Company's historical common stock prices over a time-frame similar to the expected life of the award. In addition to considering the vesting period and contractual term of the award for the expected life assumption, the Company analyzes actual historical exercise experience for previously granted awards. Restricted Stock Units (RSUs) - Employees. The Company may grant RSUs to employees of the Company. These units constitute an agreement to deliver shares of common stock to the participant at the end of the vesting period, which is defined at the date of the grant, and are forfeited should the holder’s employment terminate during the restriction period. The fair market value of the RSUs is determined on the date of the grant and is amortized over the vesting period. The vesting period is typically three years unless the recipient is retirement eligible and continued vesting is approved by the Board of Directors. The fair value of the RSUs settled in stock is based on the closing stock price on the date of grant. The weighted-average grant date fair value for 2020, 2019, and 2018 was $51.55, $58.33, and $50.35, respectively. Cash-settled RSUs are accounted for as liability-based compensation awards and adjusted based on the closing price of Materion’s common stock over the vesting period of three years. Stock-based compensation expense relating to stock-settled RSUs was $2.7 million in 2020, $2.2 million in 2019, and $1.2 million in 2018. The unamortized compensation cost on the outstanding RSUs was $4.3 million as of December 31, 2020 and is expected to be recognized over a weighted-average period of 28 months. The total fair value of shares vested during both 2020 and 2019 was $1.2 million, compared to $1.4 million in 2018. The following table summarizes the stock-settled RSU activity during 2020: (Shares in thousands) Number of Weighted- Outstanding at December 31, 2019 145 $ 50.79 Granted 84 51.55 Vested (33) 36.39 Forfeited (35) 53.52 Outstanding at December 31, 2020 161 $ 53.50 RSUs - Non-Employee Directors. In 2020, 2019, and 2018, 15,976, 11,048, and 14,728 RSUs, with a one year vesting period, were granted to certain non-employee members of the Board of Directors. The weighted-average grant date fair value of these RSUs were $48.42, $68.79, and $51.60 in 2020, 2019, and 2018, respectively. The Company recognized $0.7 million of expense with respect to these awards in each of the last three years. At December 31, 2020, $0.3 million of expense with respect to non-vested RSU awards granted to the Board of Directors has yet to be recognized and will be amortized into expense over a weighted-average period of approximately four months. Long-term Incentive Plans. Under long-term incentive compensation plans, executive officers and selected other employees receive restricted stock unit awards based upon the Company’s performance over the defined period, typically three years. Total units earned for grants made in 2020, 2019, and 2018, may vary between 0% and 200% of the units granted based on the attainment of performance targets during the related three-year period. All grants will be settled in Materion common shares and are equity classified. Vesting of performance-based awards is contingent upon the attainment of threshold performance objectives. The following table summarizes the activity related to equity-based, performance-based RSUs during 2020: (Shares in thousands) Number of Weighted- Outstanding at December 31, 2019 169 $ 52.74 Granted 46 57.65 Vested (63) 30.28 Forfeited (26) 63.59 Outstanding at December 31, 2020 126 $ 63.61 Compensation expense is based upon the performance projections for the plan period of three years, the percentage of requisite service rendered, and the fair market value of the Company’s common shares on the date of grant. The offset to the compensation expense for the portion of the award to be settled in shares is recorded within shareholders’ equity and was $2.0 million for 2020, $3.3 million for 2019, and $2.7 million for 2018. Directors' Deferred Compensation. Non-employee directors may defer all or part of their compensation into the Company’s common stock. The fair value of the deferred shares is determined at the share acquisition date and is recorded within shareholders’ equity. At December 31, 2020, shareholders’ equity included 0.1 million shares related to this plan.

Fair Value Information and Deri

Fair Value Information and Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value Information and Derivative Financial Instruments	Fair Value Information and Derivative Financial Instruments The Company measures and records financial instruments at fair value. A hierarchy is used for those instruments measured at fair value that distinguishes between assumptions based upon market data (observable inputs) and the Company's assumptions (unobservable inputs). The hierarchy consists of three levels: Level 1 — Quoted market prices in active markets for identical assets and liabilities; Level 2 — Inputs other than Level 1 inputs that are either directly or indirectly observable; and Level 3 — Unobservable inputs developed using estimates and assumptions developed by the Company, which reflect those that a market participant would use. The following table summarizes the financial instruments measured at fair value in the Consolidated Balance Sheets at December 31, 2020 and 2019: Fair Value Measurements (Thousands) Total Quoted Prices Significant Other December 31, 2020 Financial Assets Deferred compensation investments $ 3,802 $ 3,802 $ — $ — Foreign currency forward contracts 107 — 107 — Precious metal swaps 127 — 127 — Copper swaps 632 — 632 — Total $ 4,668 $ 3,802 $ 866 $ — Financial Liabilities Deferred compensation liability $ 3,802 $ 3,802 $ — $ — Foreign currency forward contracts 1,203 — 1,203 — Precious metal swaps 349 — 349 — Copper swaps 27 — 27 — Total $ 5,381 $ 3,802 $ 1,579 $ — December 31, 2019 Financial Assets Deferred compensation investments $ 3,391 $ 3,391 $ — $ — Foreign currency forward contracts 188 — 188 — Precious metal swaps 35 — 35 — Copper swaps 61 — 61 — Total $ 3,675 $ 3,391 $ 284 $ — Financial Liabilities Deferred compensation liability $ 3,391 $ 3,391 $ — $ — Foreign currency forward contracts 211 — 211 — Precious metal swaps 623 — 623 — Copper swaps 28 — 28 — Total $ 4,253 $ 3,391 $ 862 $ — The Company uses a market approach to value the assets and liabilities for financial instruments in the table above. Outstanding contracts are valued through models that utilize market observable inputs, including both spot and forward prices, for the same underlying currencies and metals. The Company's deferred compensation investments and liabilities are based on the fair value of the investments corresponding to the employees’ investment selections, primarily in mutual funds, based on quoted prices in active markets for identical assets. Deferred compensation investments are primarily presented in Other assets. Deferred compensation liabilities are primarily presented in Other long-term liabilities. The carrying values of the other working capital items and debt in the Consolidated Balance Sheets approximate fair values at December 31, 2020 and 2019. The Company uses derivative contracts to hedge portions of its foreign currency exposures and may also use derivatives to hedge a portion of its precious metal exposures. The objectives and strategies for using derivatives in these areas are as follows: Foreign Currency. The Company sells a portion of its products to overseas customers in their local currencies, primarily the euro and yen. The Company secures foreign currency derivatives, mainly forward contracts and options, to hedge these anticipated sales transactions. The purpose of the hedge program is to protect against the reduction in the dollar value of foreign currency sales from adverse exchange rate movements. Should the dollar strengthen significantly, the decrease in the translated value of the foreign currency sales should be partially offset by gains on the hedge contracts. Depending upon the methods used, the hedge contracts may limit the benefits from a weakening U.S. dollar. The use of forward contracts locks in a firm rate and eliminates any downside from an adverse rate movement as well as any benefit from a favorable rate movement. The Company may from time to time choose to hedge with options or a tandem of options known as a collar. These hedging techniques can limit or eliminate the downside risk but can allow for some or all of the benefit from a favorable rate movement to be realized. Unlike a forward contract, a premium is paid for an option; collars, which are a combination of a put and call option, may have a net premium but can be structured to be cash neutral. The Company will primarily hedge with forward contracts due to the relationship between the cash outlay and the level of risk. Precious Metals. The Company maintains the majority of its precious metal production requirements on consignment in order to reduce its working capital investment and the exposure to metal price movements. When a precious metal product is fabricated and ready for shipment to the customer, the metal is purchased out of consignment at the current market price. The price paid by the Company forms the basis for the price charged to the customer. This methodology allows for changes in either direction in the market prices of the precious metals used by the Company to be passed through to the customer and reduces the impact changes in prices could have on the Company's margins and operating profit. The consigned metal is owned by financial institutions who charge the Company a financing fee based upon the current value of the metal on hand. In certain instances, a customer may want to establish the price for the precious metal at the time the sales order is placed rather than at the time of shipment. Setting the sales price at a different date than when the material would be purchased potentially creates an exposure to movements in the market price of the metal. Therefore, in these limited situations, the Company may elect to enter into a forward contract to purchase precious metal. The forward contract allows the Company to purchase metal at a fixed price on a specific future date. The price in the forward contract serves as the basis for the price to be charged to the customer. By doing so, the selling price and purchase price are matched, and the Company's price exposure is reduced. The Company refines precious metal-containing materials for its customers and typically will purchase the refined metal from the customer at current market prices. In limited circumstances, the customer may want to fix the price to be paid at the time of the order as opposed to when the material is refined. The customer may also want to fix the price for a set period of time. The Company may then elect to enter into a hedge contract, either a forward contract or a swap, to fix the price for the estimated quantity of metal to be purchased, thereby reducing the exposure to adverse movements in the price of the metal. The Company may also enter into hedges to mitigate the risk relating to the prices of the metals which we process or refine. The Company may from time to time elect to purchase precious metal and hold in inventory rather than on consignment due to potential credit line limitations or other factors. These purchases are typically held for a short duration. A forward contract will be secured at the time of the purchase to fix the price to be used when the metal is transferred back to the consignment line, thereby limiting any price exposure during the time when the metal was owned. Copper. The Company also uses copper in its production processes. When possible, fluctuations in the purchase price of copper are passed on to customers in the form of price adders or reductions. While over time the Company's price exposure to copper is generally in balance, there can be a lag between the change in the Company's cost and the pass-through to its customers, resulting in higher or lower margins in a given period. To mitigate this impact, the Company hedges a portion of this pricing risk. A team consisting of senior financial managers reviews the estimated exposure levels, as defined by budgets, forecasts, and other internal data, and determines the timing, amounts, and instruments to use to hedge exposures. Management analyzes the effective hedged rates and the actual and projected gains and losses on the hedging transactions against the program objectives, targeted rates, and levels of risk assumed. Foreign currency contracts are typically layered in at different times for a specified exposure period in order to minimize the impact of market rate movements. The use of derivatives is governed by policies adopted by the Audit and Risk Committee of the Board of Directors. The Company will only enter into a derivative contract if there is an underlying identified exposure. Contracts are typically held to maturity. The Company does not engage in derivative trading activities and does not use derivatives for speculative purposes. The Company only uses hedge contracts that are denominated in the same currency or metal as the underlying exposure. All derivatives are recorded on the balance sheet at fair value. If the derivative is designated and effective as a cash flow hedge, changes in the fair value of the derivative are recognized in OCI until the hedged item is recognized in earnings. The ineffective portion of a derivative’s fair value, if any, is recognized in earnings immediately. If a derivative is not a hedge, changes in the fair value are adjusted through income. The fair values of the outstanding derivatives are recorded on the balance sheet as assets (if the derivatives are in a gain position) or liabilities (if the derivatives are in a loss position). The fair values will also be classified as short-term or long-term depending upon their maturity dates. The following table summarizes the notional amount and the fair value of the Company’s outstanding derivatives not designated as hedging instruments (on a gross basis) and balance sheet classification as of December 31, 2020 and 2019: December 31, 2020 December 31, 2019 (Thousands) Notional Fair Notional Fair Foreign currency forward contracts Prepaid expenses $ 62,012 $ 107 $ 13,734 $ 95 Other liabilities and accrued items 7,695 55 5,757 16 These outstanding foreign currency derivatives were related to balance sheet hedges and intercompany loans. Other-net included foreign currency gains relating to these derivatives of $2.7 million in 2020, primarily due to a gain realized on the settlement of a foreign currency hedge for the purchase of Optics Balzers. In 2019, Other-net included $0.1 million of foreign currency losses relating to these derivatives. The following table summarizes the notional amount and the fair value of the Company’s outstanding derivatives designated as cash flow hedges (on a gross basis) and balance sheet classification at December 31, 2020 and 2019: December 31, 2020 December 31, 2019 (Thousands) Notional Fair Notional Fair Prepaid expenses Foreign currency forward contracts - yen $ — $ — $ 1,025 $ 10 Foreign currency forward contracts - euro — — 3,466 83 Precious metal swaps 2,155 127 1,116 34 Copper swaps 6,225 632 1,951 61 8,380 759 7,558 188 Other assets Precious metal swaps — — 157 1 Other liabilities and accrued items Foreign currency forward contracts - yen 2,668 59 2,355 12 Foreign currency forward contracts - euro 17,611 1,089 15,686 183 Precious metal swaps 4,964 349 7,034 618 Copper swaps 2,445 27 1,266 28 27,688 1,524 26,341 841 Other long-term liabilities Precious metal swaps — — 149 5 Total $ 36,068 $ 765 $ 34,205 $ 657 All of these contracts were designated and effective as cash flow hedges. No ineffectiveness expense was recorded in 2020, 2019, or 2018. The fair value of derivative contracts recorded in accumulated other comprehensive loss totaled $0.8 million and $0.7 million as of December 31, 2020 and December 31, 2019, respectively. Deferred losses of $0.8 million at December 31, 2020 are expected to be reclassified to earnings within the next 18-month period. The following table summarizes the pre-tax amounts reclassified from accumulated other comprehensive income relating to the hedging relationship of the Company’s outstanding derivatives designated as cash flow hedges and income statement classification for years ended December 31, 2020 and 2019: (Thousands) 2020 2019 Hedging relationship Line item Foreign currency forward contracts Net sales $ 222 $ (29) Precious metal swaps Cost of sales 2,041 595 Copper swaps Cost of sales 354 393 Total $ 2,617 $ 959 The derivative activity in the table above is reflected in cash flows from operating activities.

Contingencies and Commitments

Contingencies and Commitments	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Contingencies and Commitments	Contingencies and Commitments Beryllium Cases The Company is a defendant from time to time in proceedings in various state and federal courts brought by plaintiffs alleging that they have contracted, or have been placed at risk of contracting, beryllium sensitization or Chronic Beryllium Disease (CBD) or related ailments as a result of exposure to beryllium. Plaintiffs in beryllium cases seek recovery under theories of negligence and various other legal theories and seek compensatory and punitive damages, in many cases of an unspecified sum. Spouses, if any, often claim loss of consortium. Employee cases, in which plaintiffs have a high burden of proof, have historically involved relatively small losses to the Company. Third-party plaintiffs (typically employees of customers) face a lower burden of proof than do the Company’s employees, but these cases have generally been covered by varying levels of insurance. Management has vigorously contested the beryllium cases brought against the Company. Non-employee beryllium cases are covered by insurance, subject to certain limitations. The insurance covers defense costs and indemnity payments (resulting from settlements or court verdicts) and is subject to various levels of deductibles. Defense and indemnity costs were less than or equal to the deductible in both 2020 and 2019. As of December 31, 2020, the Company was a defendant in two beryllium litigation cases, one of which was outstanding as of December 31, 2019. The Company does not expect the resolution of these matters to have a material impact on its consolidated financial statements. Although it is not possible to predict the outcome of any pending litigation, the Company provides for costs related to litigation matters when a loss is probable, and the amount is reasonably estimable. Litigation is subject to many uncertainties, and it is possible that some of the actions could be decided unfavorably in amounts exceeding the Company’s reserves. An unfavorable outcome or settlement of a beryllium case or adverse media coverage could encourage the commencement of additional similar litigation. The Company is unable to estimate its potential exposure to unasserted claims. Based upon currently known facts and assuming collectibility of insurance, the Company does not believe that resolution of the current or any potential future beryllium proceedings will have a material adverse effect on the financial condition or cash flow of the Company. However, the Company’s results of operations could be materially affected by unfavorable results in one or more cases. Environmental Proceedings The Company has an active program for environmental compliance that includes the identification of environmental projects and estimating the impact on the Company’s financial performance and available resources. Environmental expenditures that relate to current operations, such as wastewater treatment and control of airborne emissions, are either expensed or capitalized as appropriate. The Company records reserves for the probable costs for identified environmental remediation projects. The Company’s environmental engineers perform routine ongoing analyses of the remediation sites and will use outside consultants to assist in their analyses from time to time. Accruals are based upon their analyses and are established based on the reasonably estimable loss or range of loss. The accruals are revised for the results of ongoing studies, changes in strategies, inflation, and for differences between actual and projected costs. The accruals may also be affected by rulings and negotiations with regulatory agencies. The timing of payments often lags the accrual, as environmental projects typically require a number of years to complete. The environmental reserves recorded represent the Company's best estimate of what is reasonably possible and cover existing or currently foreseen projects based upon current facts and circumstances. The Company does not believe that it is reasonably possible that the cost to resolve environmental matters for sites where the investigative work and work plan development are substantially complete will be materially different than what has been accrued while the ultimate loss contingencies for sites that are in the preliminary stages of investigation cannot be reasonably determined at the present time. As facts and circumstances change, the ultimate cost may be revised, and the recording of additional costs may be material in the period in which the additional costs are accrued. The Company does not believe that the ultimate liability for environmental matters will have a material impact on its financial condition or liquidity due to the nature of known environmental matters and the extended period of time during which environmental remediation normally takes place. The undiscounted reserve balance at the beginning of the year, the amounts expensed and paid, and the balance at December 31, 2020 and 2019 are as follows: (Thousands) 2020 2019 Reserve balance at beginning of year $ 5,937 $ 6,521 Expensed 288 482 Paid (749) (1,066) Reserve balance at end of year $ 5,476 $ 5,937 Ending balance recorded in: Other liabilities and accrued items $ 845 $ 982 Other long-term liabilities 4,631 4,955 The majority of spending in both 2020 and 2019 was for various remediation projects at the Elmore, Ohio plant site. Asset Retirement Obligations The Company has asset retirement obligations related to its mine in Utah, as well as for certain leased facilities where the Company is contractually obligated to restore the facility back to its original condition at the end of the lease. The following represents a roll forward of the Company's asset retirement obligation liabilities for the years ended December 31, 2020 and 2019: (Thousands) 2020 2019 Asset retirement obligation at beginning of period $ 1,421 $ 1,257 Accretion expense 137 164 Change in liability 207 — Asset retirement obligation at end of period $ 1,765 $ 1,421 These obligations are reflected in Other long-term liabilities on the Consolidated Balance Sheet. Other The Company is subject to various legal or other proceedings that relate to the ordinary course of its business. The Company believes that the resolution of these proceedings, individually or in the aggregate, will not have a material adverse impact upon the Company’s consolidated financial statements. On October 14, 2020 Garett Lucyk, et al. v. Materion Brush Inc., et. al. , case number 20CV0234, a wage and hour purported collective and class action, was filed in the Northern District of Ohio against the Company and its subsidiary, Materion Brush Inc. (collectively, the Company). Plaintiff, a former hourly production employee at the Company's Elmore, Ohio facility, alleges that he and other similarly situated employees nationwide are not paid for all time they spend donning and doffing personal protective equipment in violation of the Fair Labor Standards Act and Ohio law. Plaintiff also alleges the Company failed to include all remuneration he and others received for premium and bonus pay when computing overtime pay. The case is currently in the preliminary stages. The Company believes that it has substantive defenses and intends to vigorously defend this suit. At December 31, 2020, the Company had outstanding letters of credit totalin g $48.1 million related to workers’ compensation, consigned precious metal guarantees, environmental remediation issues, and other matters. The majority of the Company's outstanding letters of credit expire in 2021 and are expected to be renewed.

Quarterly Data (Unaudited)

Quarterly Data (Unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Quarterly Data (Unaudited)	Quarterly Data (Unaudited) The following tables summarize selected quarterly financial data for the years ended December 31, 2020 and 2019: 2020 (Thousands except per share amounts) First Second Third Fourth Total Net sales $ 277,946 $ 271,468 $ 287,171 $ 339,689 $ 1,176,274 Gross margin 44,570 46,955 45,311 55,797 192,633 Percent of net sales 16.0 % 17.3 % 15.8 % 16.4 % 16.4 % Net (loss) income (1) $ (3,878) $ 5,803 $ 5,471 $ 8,066 $ 15,462 Net (loss) income per share of common stock: Basic $ (0.19) $ 0.29 $ 0.27 $ 0.40 0.76 Diluted (2) (0.19) 0.28 0.27 0.39 0.75 2019 First Second Third Fourth Total Net sales $ 301,441 $ 297,843 $ 305,979 $ 280,161 $ 1,185,424 Gross margin 69,606 71,997 66,605 54,482 262,690 Percent of net sales 23.1 % 24.2 % 21.8 % 19.4 % 22.2 % Net income (3) $ 17,133 $ 17,393 $ 4,522 $ 14,346 $ 53,394 Net income per share of common stock: Basic $ 0.85 $ 0.85 $ 0.22 $ 0.70 $ 2.62 Diluted 0.83 0.84 0.22 0.69 2.59 (1) The net loss for the first quarter of 2020 includes the impact of $10.8 million of non-cash impairment charges. See Note N for additional information. (2) Since the Company reported a net loss for the first quarter of 2020, the effect of potential common shares were excluded from diluted earnings per share, as their inclusion would have been anti-dilutive. (3) Net income for the third quarter of 2019 includes the impact of $14.1 million of non-cash impairment charges. For additional information refer to Note N. * Certain amounts have been adjusted to reflect the change in inventory accounting method, as described in Note A. The Company follows a 13-week quarterly accounting cycle pursuant to which the first three fiscal quarters end on a Friday and the fiscal year always ends on December 31.

Valuation And Qualifying Accoun

Valuation And Qualifying Accounts	12 Months Ended
	Dec. 31, 2020
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts	Materion Corporation and Subsidiaries Schedule II—Valuation and Qualifying Accounts (Thousands) Allowance for uncollectible accounts: 2020 2019 2018 Balance at Beginning of Period $ 392 $ 616 $ 640 Additions: Charged to Costs and Expenses (1) 224 (39) 271 Deductions (2) (80) (185) (295) Balance at End of Period $ 536 $ 392 $ 616 Allowance for inventory reserves: 2020 2019* 2018* Balance at Beginning of Period $ 14,697 $ 13,065 $ 14,381 Additions: Charged to Costs and Expenses (3) 9,282 2,367 3,175 Deductions (4) (1,830) (735) (4,491) Balance at End of Period $ 22,149 $ 14,697 $ 13,065 Valuation allowance on deferred tax assets: 2020 2019 2018 Balance at Beginning of Period $ 17,676 $ 15,917 $ 16,246 Additions: Charged to Costs and Expenses (5) 884 2,475 9,700 Deductions (6) (4,426) (716) (10,029) Balance at End of Period $ 14,134 $ 17,676 $ 15,917 (1) Provision for uncollectible accounts included in expenses. (2) Bad debts written-off, net of recoveries (3) Provisions for surplus and obsolete inventory and lower cost or net realizable value included in expenses. (4) Inventory write-offs. (5) Increase in valuation allowance is recorded as a component of the provision for income taxes. (6) Includes valuation allowances recorded against other comprehensive income. *Certain amounts have been adjusted to reflect the change in inventory accounting method, as described in Note A to the Consolidated Financial Statements.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Organization	Organization: Materion Corporation (the Company) is a holding company with subsidiaries that have operations in the United States, Europe, and Asia. These operations manufacture advanced engineered materials used in a variety of end markets, including semiconductor, industrial, aerospace and defense, automotive, energy, consumer electronics, and telecom and data center. The Company has four reportable segments: Performance Alloys and Composites, Advanced Materials, Precision Optics, and Other. Other includes unallocated corporate costs. Refer to Note C for additional segment details. The Company distributes its products through a combination of company-owned facilities and independent distributors and agents.
Business Combinations	Business Combinations: The Company records assets acquired and liabilities assumed at the date of acquisition at their respective fair values. Intangible assets acquired in a business combination are recognized and reported apart from goodwill. Goodwill represents the excess purchase price over the fair value of the tangible net assets and intangible assets acquired in a business combination. Acquisition-related expenses are recognized separately from the business combination and are expensed as incurred. The amounts reflected in Note B to the Consolidated Financial Statements are the results of the preliminary purchase price allocation for the Optics Balzers acquisition and will be updated upon completion of the final valuation. The Company is required to complete the purchase price allocation within 12 months of the acquisition date. If such completion of the allocation results in a change in the preliminary values, the measurement period adjustment will be recognized in the period in which the adjustment amount is determined.
Use of Estimates	Use of Estimates: The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results may differ from those estimates.
Change in Accounting Principle	Change in Accounting Principle: During the fourth quarter of 2020, the Company changed its method of accounting for certain domestic inventory from the last-in, first-out (LIFO) method to the first-in, first-out (FIFO) method. All prior periods presented have been retroactively adjusted to apply the new method of accounting.
Consolidation	Consolidation: The Consolidated Financial Statements include the accounts of Materion Corporation and its subsidiaries. All of the Company’s subsidiaries were wholly owned as of December 31, 2020. Intercompany accounts and transactions are eliminated in consolidation.
Cash Equivalents	Cash Equivalents:  All highly liquid investments with a maturity of three months or less when purchased are considered to be cash equivalents.
Accounts Receivable	Accounts Receivable: An allowance for doubtful accounts is maintained for the expected losses resulting from the inability of customers to pay amounts due. The Company considers the current market conditions and credit losses related to the Company's trade receivables based on the macroeconomic environment, geographic considerations, and other expected market trends. Additionally, the allowance is based upon identified delinquent accounts, customer payment patterns, and other analyses of historical data and trends. Accounts receivable were net of an allowance for credit losses of $0.5 million and $0.4 million at December 31, 2020 and 2019, respectively. The change in the allowance for credit losses includes expense and net write-offs, none of which are material. The Company extends credit to customers based upon their financial condition, and collateral is not generally required.
Property, Plant and Equipment	Property, Plant, and Equipment: Property, plant, and equipment is stated on the basis of cost. Depreciation is computed principally by the straight-line method, except certain assets for which depreciation may be computed by the units-of-production method. The depreciable lives that are used in computing the annual provision for depreciation by class of asset are primarily as follows: Years Land improvements 10 to 20 Buildings 20 to 40 Leasehold improvements Life of lease Machinery and equipment 3 to 15 Furniture and fixtures 4 to 10 Automobiles and trucks 3 to 8 Research equipment 3 to 10 Computer hardware 3 to 10 Computer software 3 to 10 An asset acquired under a finance lease will be recorded at the lesser of the present value of the projected lease payments or the fair value of the asset and will be depreciated in accordance with the above schedule. Leasehold improvements will be depreciated over the life of the improvement if it is shorter than the life of the lease. Repair and maintenance costs are expensed as incurred.
Mineral Resources and Mine Development	Mineral Resources and Mine Development: Property acquisition costs are capitalized as mineral resources on the balance sheet and are depleted using the units-of-production method based upon total estimated recoverable proven reserves of the beryllium-bearing bertrandite ore body. The Company uses beryllium pounds as the unit of accounting measure, and depletion expense is recorded on a pro-rata basis based upon the amount of beryllium pounds extracted as a percentage of total estimated beryllium pounds contained in all ore bodies. Mine development costs at the Company's open pit surface mine include drilling, infrastructure, and other related costs to delineate an ore body, and the removal of overburden to initially expose an ore body. Before mineralization is classified as proven and probable reserves, costs are classified as exploration expense. Capitalization of mine development project costs that meet the definition of an asset begins once mineralization is classified as proven and probable reserves. Historically, the Company’s mine development costs involved the development of a new source of ore, and, as such, mine development costs incurred were capitalized during the pre-production phase of a mine and amortized into inventory as the ore was extracted. In 2020, the Company expanded a mine to further develop an ore body. Since the pre-production phase ended when ore was first extracted from this mine, the Company recognized approximately $12.9 million of mine development costs in 2020 as a component of cost of sales. This expansion is expected to benefit future periods. Drilling and related costs are capitalized for an ore body where proven and probable reserves exist, and the activities are directed at obtaining additional information on the ore body. All other drilling and related costs are expensed as incurred. Drilling costs incurred during the production phase for operational ore control are allocated to inventory costs and then included as a component of costs applicable to sales. The costs of removing overburden and waste materials to access the ore body at an open-pit mine prior to the production phase are capitalized during the development of an open-pit mine and are capitalized at each pit. These costs are amortized as the ore is extracted using the units-of-production method based upon total estimated recoverable proven reserves for the individual pit. The Company uses beryllium pounds as the unit of accounting measure for recording amortization. To the extent that the aforementioned costs benefit an entire ore body, the costs are amortized over the estimated useful life of the ore body. Costs incurred to access specific ore blocks or areas that only provide benefit over the life of that area are amortized over the estimated life of that specific ore block area.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets: Goodwill is reviewed annually for impairment or more frequently if impairment indicators arise. The Company conducts its annual goodwill and indefinite-lived intangible asset impairment assessment as of the first day of the fourth quarter, or more frequently under certain circumstances. For the purpose of the goodwill impairment assessment, the Company has the option to perform a qualitative assessment (commonly referred to as "step zero") to determine whether further quantitative analysis for impairment of goodwill or indefinite-lived intangible assets is necessary or a quantitative assessment ("step one") where the Company estimates the fair value of each reporting unit using a discounted cash flow method (income approach). Goodwill is assigned to the reporting unit, which is the operating segment level or one level below the operating segment. Intangible assets with finite lives are amortized using the straight-line method or effective interest
Asset Impairment	Long-Lived Asset Impairment: Management performs impairment tests of long-lived assets, including property and equipment, whenever an event occurs or circumstances change that indicate that the carrying value may not be recoverable or the useful life of the asset has changed. Upon indications of impairment, assets and liabilities are grouped at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities. The asset group would be considered impaired when the estimated future undiscounted cash flows generated by the asset group are less than its carrying value. If such undiscounted cash flows indicate that the carrying value of the asset group is not recoverable, impairment losses are measured by comparing the estimated fair value of the asset group to its carrying amount.
Derivatives	Derivatives: The Company recognizes all derivatives on the balance sheet at fair value. If the derivative is designated and effective as a cash flow hedge, changes in the fair value of the derivative are recognized in other comprehensive income, a component of shareholders’ equity, until the hedged item is recognized in earnings. If the derivative is designated as a fair value hedge, changes in fair value are offset against the change in the fair value of the hedged asset, liability, or commitment through earnings. The ineffective portion of a derivative’s change in fair value, if any, is recognized in earnings immediately. If a derivative is not a hedge, changes in its fair value are adjusted through the income statement.
Asset Retirement Obligation	Asset Retirement Obligation:  The Company records a liability to recognize the legal obligation to remove an asset at the time the asset is acquired or when the legal liability arises. The liability is recorded for the present value of the ultimate obligation by discounting the estimated future cash flows using a credit-adjusted risk-free interest rate. The liability is accreted over time, with the accretion charged to expense. An asset equal to the fair value of the liability is recorded concurrent with the liability and depreciated over the life of the underlying asset.
Unearned Income	Unearned Income: Expenditures for capital equipment to be reimbursed under government contracts are recorded in property, plant, and equipment, while the reimbursements for those expenditures are recorded in unearned income, a liability on the balance sheet. When the assets subject to reimbursement are placed in service, the total cost is depreciated over the useful lives, and the unearned income liability is reduced and credited to cost of sales on the Consolidated Statements of Income ratably with the annual depreciation expense. Also included in Unearned Income as of December 31, 2020 are $58.8 million of customer prepayments. See Note L for additional discussion.
Advertising Costs	Advertising Costs: The Company expenses all advertising costs as incurred. Advertising costs were $0.3 million in 2020, $0.7 million in 2019, and $1.2 million in 2018.
Stock-based Compensation	Stock-based Compensation: The Company recognizes stock-based compensation expense based on the grant date fair value of the award over the period during which an employee is required to provide service in exchange for the award. Stock-based awards include performance-based restricted stock units (PRSUs), restricted stock units (RSUs), and stock appreciation rights (SARs). The fair value of PRSUs and RSUs is primarily based on the closing market price of a share of the Company's common stock on the date of grant, modified as appropriate to take into account the features of such grants. SARs are granted with an exercise price equal to the closing price of the Company's common shares on the date of grant. The fair value of SARs is determined using a Black-Scholes option-pricing model, which incorporates assumptions regarding the expected volatility, the expected option life, the risk-free interest rate, and the expected dividend yield. See Note R for additional information about stock-based compensation.
Capitalized Interest	Capitalized Interest: Interest expense associated with active capital asset construction and mine development projects is capitalized and amortized over the future useful lives of the related assets.
Income Taxes	Income Taxes: The Company uses the liability method in measuring the provision for income taxes and recognizing deferred tax assets and liabilities on the balance sheet. The Company will record a valuation allowance to reduce the deferred tax assets to the amount that is more likely than not to be realized, as warranted by current facts and circumstances. The Company applies a more-likely-than-not recognition threshold for all tax uncertainties and will record a liability for those tax benefits that have a less than 50% likelihood of being sustained upon examination by the taxing authorities.
Net Income Per Share	Net Income Per Share: Basic earnings per share (EPS) is computed by dividing income available to common stockholders by the weighted-average number of common shares outstanding for the period. Diluted EPS reflects the assumed conversion of all dilutive common stock equivalents as appropriate using the treasury stock method.
New Pronouncements	New Pronouncements Adopted: In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-13, Financial Instruments - Credit Losses . This ASU requires an entity to change its accounting approach in determining impairment of certain financial instruments, including trade receivables, from an “incurred loss” to a “current expected credit loss” model. The standard is effective for fiscal years beginning after December 15, 2019, including interim periods within such fiscal years. The Company adopted this guidance as of January 1, 2020, and the adoption did not have a material effect on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU 2018-14 Defined Benefit Plans (Topic 715-20) - Changes to the Disclosure Requirements for Defined Benefit Plans, which intends to improve disclosure effectiveness by adding, removing, or clarifying certain disclosure requirements related to defined benefit pension or other postretirement plans . The standard is effective for fiscal years ending after December 15, 2020. The Company adopted this guidance as of December 31, 2020. The effect of the adoption did not materially impact the Company's financial statements or related disclosures.
Inventories	Inventories: Inventories are stated at the lower of cost or net realizable value. In the fourth quarter of 2020, the Company voluntarily changed its method of inventory costing for the majority of its domestic inventories to the FIFO method from the LIFO method. Except for its bertrandite ore mine which values inventory using a weighted average cost method, the Company's remaining inventories are valued using the FIFO method. The Company believes that a current costing method is preferable as it improves comparability with its most similar peers, it more closely resembles the physical flow of its inventory (i.e., it provides better matching of revenues and expenses), and it results in uniformity across a significant majority of the Company’s inventory. Prior to the change in method, inventories valued on the LIFO cost method were approximately 45% of the Company's total inventories as of December 31, 2020. The effects of the change in accounting principle from LIFO to FIFO have been retrospectively applied to all periods presented. As a result of the retrospective application of the change in accounting principle, certain financial statement line items in the Company’s consolidated balance sheets as of December 31, 2019 and the consolidated statements of income, comprehensive income, shareholders’ equity, and cash flows for the years ended December 31, 2019 and 2018 were adjusted as necessary.

Revenue Recognition (Policies)

Revenue Recognition (Policies)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue Recognition, Policy	Net sales consist primarily of revenue from the sale of precious and non-precious specialty metals, beryllium and copper-based alloys, beryllium composites, and other products into numerous end markets. The Company requires an agreement with a customer that creates enforceable rights and performance obligations. The Company generally recognizes revenue, in an amount that reflects the consideration to which it expects to be entitled, upon satisfaction of a performance obligation by transferring control over a product to the customer. Control over the product is generally transferred to the customer when the Company has a present right to payment, the customer has legal title, the customer has physical possession, the customer has the significant risks and rewards of ownership, and/or the customer has accepted the product. Shipping and Handling Costs : The Company accounts for shipping and handling activities related to contracts with customers as costs to fulfill its promise to transfer the associated products. Accordingly, customer payments for shipping and handling costs are recorded as a component of net sales, and related costs are recorded as a component of cost of sales. Taxes Collected from Customers and Remitted to Governmental Authorities : Revenue is recorded net of taxes collected from customers that are remitted to governmental authorities, with the collected taxes recorded as current liabilities until remitted to the relevant government authority. Product Warranty : Substantially all of the Company’s customer contracts contain a warranty that provides assurance that the purchased product will function as expected and in accordance with certain specifications. The warranty is intended to safeguard the customer against existing defects and does not provide any incremental service to the customer. Transaction Price Allocated to Future Performance Obligations: ASC 606 requires that the Company disclose the aggregate amount of transaction price that is allocated to performance obligations that have not yet been satisfied at December 31, 2020. Remaining performance obligations include non-cancelable purchase orders and customer contracts. The guidance provides certain practical expedients that limit this requirement. As such, the Company does not disclose the value of unsatisfied performance obligations for contracts with an original expected length of one year or less. After considering the practical expedient, at December 31, 2020, the aggregate amount of the transaction price allocated to remaining performance obligations was approximate ly $10.2 million . Contract Costs : The Company recognizes the incremental costs of obtaining contracts as an expense when incurred if the amortization period of the assets that the Company otherwise would have recognized is one year or less. These costs primarily relate to sales commissions, which are included in selling, general, and administrative expenses. Contract Balances : The timing of revenue recognition, billings, and cash collections resulted in the following contract assets and contract liabilities: (Thousands) December 31, 2020 December 31, 2019 $ change % change Accounts receivable, trade $ 156,821 $ 141,168 $ 15,653 11 % Unbilled receivables 8,832 13,583 (4,751) (35) % Unearned revenue 7,713 3,380 4,333 128 % Accounts receivable, trade represents payments due from customers relating to the transfer of the Company’s products and services. The Company believes that its receivables are collectible and appropriate allowances for doubtful accounts have been recorded. Impairment losses (bad debt) incurred relating to our receivables were immaterial during 2020. Unbilled receivables represent expenditures on contracts, plus applicable profit margin, not yet billed. Unbilled receivables are normally billed and collected within one year. Billings made on contracts are recorded as a reduction of unbilled receivables. Unearned revenue is recorded for consideration received from customers in advance of satisfaction of the related performance obligations. The Company recognized approximately $3.2 million of the December 31, 2019 unearned amounts as revenue during 2020. As a practical expedient, the Company does not adjust the promised amount of consideration for the effects of a significant financing component because the period between the transfer of a product or service to a customer and when the customer pays for that product or service will be one year or less. The Company does not include extended payment terms in its contracts with customers.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of depreciable lives by class of assets	The depreciable lives that are used in computing the annual provision for depreciation by class of asset are primarily as follows: Years Land improvements 10 to 20 Buildings 20 to 40 Leasehold improvements Life of lease Machinery and equipment 3 to 15 Furniture and fixtures 4 to 10 Automobiles and trucks 3 to 8 Research equipment 3 to 10 Computer hardware 3 to 10 Computer software 3 to 10
Accounting Standards Update and Change in Accounting Principle	As a result of the retrospective application of this change in accounting method, the following financial statement line items within the accompanying financial statements were adjusted, as follows: Consolidated Statements of Income (Thousands except per share amounts) 2020 2019 2018 Selected Items As Computed Under LIFO As Reported Under FIFO Difference Previously Reported As Adjusted Adjustment Previously Reported As Adjusted Adjustment Cost of sales $ 981,722 $ 983,641 $ 1,919 $ 926,280 $ 922,734 $ (3,546) $ 956,710 $ 956,454 $ (256) Gross margin 194,552 192,633 (1,919) 259,144 262,690 3,546 251,105 251,361 256 Operating profit 10,134 8,215 (1,919) 67,000 70,546 3,546 61,496 61,752 256 Income before income taxes 10,194 8,275 (1,919) 61,990 65,536 3,546 16,342 16,598 256 Income tax (benefit) expense (6,748) (7,187) (439) 11,330 12,142 812 (4,504) (4,446) 58 Net income 16,942 15,462 (1,480) 50,660 53,394 2,734 20,846 21,044 198 Basic earnings per share: Net income per share of common stock $ 0.83 $ 0.76 $ (0.07) $ 2.49 $ 2.62 $ 0.13 $ 1.03 $ 1.04 $ 0.01 Diluted earnings per share: Net income per share of common stock $ 0.82 $ 0.75 $ (0.07) $ 2.45 $ 2.59 $ 0.14 $ 1.01 $ 1.02 $ 0.01 Consolidated Statements of Comprehensive Income (Thousands) 2020 2019 2018 Selected Items As Computed Under LIFO As Reported Under FIFO Difference Previously Reported As Adjusted Adjustment Previously Reported As Adjusted Adjustment Net income $ 16,942 $ 15,462 $ (1,480) $ 50,660 $ 53,394 $ 2,734 $ 20,846 $ 21,044 $ 198 Comprehensive income 23,765 22,285 (1,480) 63,432 66,166 2,734 65,549 65,747 198 Consolidated Balance Sheets (Thousands) 2020 2019 Selected Items As Computed Under LIFO As Reported Under FIFO Difference Previously Reported As Adjusted Adjustment Inventories, net $ 206,834 $ 250,778 $ 43,944 $ 190,390 $ 236,253 $ 45,863 Prepaid and other current assets 23,470 20,896 (2,574) 21,839 21,736 (103) Deferred income taxes (liability) 8,081 15,864 7,783 2,410 13,104 10,694 Retained earnings 597,471 631,058 33,587 589,888 624,954 35,066 Consolidated Statements of Cash Flows (Thousands) 2020 2019 2018 Selected Items As Computed Under LIFO As Reported Under FIFO Difference Previously Reported As Adjusted Adjustment Previously Reported As Adjusted Adjustment Net income $ 16,942 $ 15,462 $ (1,480) $ 50,660 $ 53,394 $ 2,734 $ 20,846 $ 21,044 $ 198 Deferred income tax (benefit) expense (6,940) (9,850) (2,910) 2,584 3,945 1,361 (1,318) (1,912) (594) Decrease (increase) in inventory (3,207) (1,288) 1,919 24,031 20,485 (3,546) 4,234 3,978 (256) Decrease (increase) in prepaid and other current assets 4 2,475 2,471 1,418 869 (549) 1,162 1,814 652 As a result of the retrospective application of this change in accounting principle, the following financial statement line items within the unaudited interim 2020 and 2019 quarterly condensed consolidated financial statements were adjusted, as follows: Quarterly Data (unaudited) (Thousands except per share amounts) 2020 First Quarter Second Quarter Selected Items Previously Reported As Adjusted Adjustment Previously Reported As Adjusted Adjustment Cost of sales $ 232,371 $ 233,376 $ 1,005 $ 223,378 $ 224,513 $ 1,135 Gross margin 45,575 44,570 (1,005) 48,090 46,955 (1,135) Operating (loss) profit (4,563) (5,568) (1,005) 8,706 7,571 (1,135) (Loss) Income before income taxes (3,865) (4,870) (1,005) 8,298 7,163 (1,135) Income tax (benefit) expense (762) (992) (230) 1,620 1,360 (260) Net (loss) income (3,103) (3,878) (775) 6,678 5,803 (875) Basic earnings per share: Net (loss) income per share of common stock $ (0.15) $ (0.19) $ (0.04) $ 0.33 $ 0.29 $ (0.04) Diluted earnings per share: Net (loss) income per share of common stock $ (0.15) $ (0.19) $ (0.04) $ 0.32 $ 0.28 $ (0.04) (Thousands except per share amounts) 2020 Third Quarter Fourth Quarter Selected Items Previously Reported As Adjusted Adjustment As Computed Under LIFO As Reported Difference Cost of sales $ 240,531 $ 241,860 $ 1,329 $ 285,442 $ 283,892 $ (1,550) Gross margin 46,640 45,311 (1,329) 54,247 55,797 1,550 Operating (loss) profit 713 (616) (1,329) 5,278 6,828 1,550 (Loss) Income before income taxes 455 (874) (1,329) 5,306 6,856 1,550 Income tax (benefit) expense (6,041) (6,345) (304) (1,565) (1,210) 355 Net income 6,496 5,471 (1,025) 6,871 8,066 1,195 Basic earnings per share: Net income per share of common stock $ 0.32 $ 0.27 $ (0.05) $ 0.34 $ 0.40 $ 0.06 Diluted earnings per share: Net income per share of common stock $ 0.32 $ 0.27 $ (0.05) $ 0.33 $ 0.39 $ 0.06 (Thousands except per share amounts) 2019 First Quarter Second Quarter Selected Items Previously Reported As Adjusted Adjustment Previously Reported As Adjusted Adjustment Cost of sales $ 232,129 $ 231,835 $ (294) $ 228,249 $ 225,846 $ (2,403) Gross margin 69,312 69,606 294 69,594 71,997 2,403 Operating profit 21,387 21,681 294 22,750 25,153 2,403 Income before income taxes 20,676 20,970 294 19,138 21,541 2,403 Income tax expense 3,770 3,837 67 3,598 4,148 550 Net income 16,906 17,133 227 15,540 17,393 1,853 Basic earnings per share: Net income per share of common stock $ 0.83 $ 0.85 $ 0.02 $ 0.76 $ 0.85 $ 0.09 Diluted earnings per share: Net income per share of common stock $ 0.82 $ 0.83 $ 0.01 $ 0.75 $ 0.84 $ 0.09 (Thousands except per share amounts) 2019 Third Quarter Fourth Quarter Selected Items Previously Reported As Adjusted Adjustment Previously Reported As Adjusted Adjustment Cost of sales $ 240,748 $ 239,374 $ (1,374) $ 225,154 $ 225,679 $ 525 Gross margin 65,231 66,605 1,374 55,007 54,482 (525) Operating profit 6,289 7,663 1,374 16,574 16,049 (525) Income before income taxes 5,726 7,100 1,374 16,450 15,925 (525) Income tax expense 2,263 2,578 315 1,699 1,579 (120) Net income 3,463 4,522 1,059 14,751 14,346 (405) Basic earnings per share: Net income per share of common stock $ 0.17 $ 0.22 $ 0.05 $ 0.72 $ 0.70 $ (0.02) Diluted earnings per share: Net income per share of common stock $ 0.17 $ 0.22 $ 0.05 $ 0.71 $ 0.69 $ (0.02)

Acquisition (Tables)

Acquisition (Tables)	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	The preliminary purchase price allocation for the acquisition is as follows: (Thousands) July 17, 2020 Assets: Cash and cash equivalents $ 5,390 Accounts receivable 8,484 Inventories 10,715 Prepaid and other current assets 937 Property, plant, and equipment 46,791 Operating lease, right-of-use assets 13,357 Intangible assets 49,300 Goodwill 70,639 Total assets acquired $ 205,613 Liabilities: Short-term debt $ 600 Accounts payable 2,851 Salaries and wages 4,392 Other liabilities and accrued items 3,678 Income taxes 61 Unearned revenue 1,259 Other long-term liabilities 207 Operating lease liabilities 12,356 Finance lease liabilities 2,642 Retirement and post-employment benefits 6,586 Unearned income 1,835 Long-term income taxes 181 Deferred income taxes 10,934 Long-term debt 21,926 Total liabilities assumed $ 69,508 Net assets acquired $ 136,105
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination	The following table reports the intangible assets by asset category as of the closing date: (Thousands) Value at Acquisition Weighted Average Life Customer relationships $ 40,141 18 years Technology 4,059 5 years Licenses and other 5,100 5 years Total $ 49,300

Segment Reporting and Geograp_2

Segment Reporting and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment Reporting	Financial information for reportable segments was as follows: (Thousands) Performance Advanced Materials Precision Optics Other Total 2020 Net sales $ 394,195 $ 670,867 $ 111,212 $ — $ 1,176,274 Intersegment sales 6 35,912 — — 35,918 Operating profit (loss) 13,597 22,120 (4,382) (23,120) 8,215 Depreciation, depletion, and amortization 25,782 8,061 6,564 1,977 42,384 Expenditures for long-lived assets 53,841 9,003 908 3,522 67,274 Total Assets 477,892 251,637 268,004 60,327 1,057,860 2019 Net sales $ 500,201 $ 573,763 $ 111,460 $ — $ 1,185,424 Intersegment sales 38 70,047 — — 70,085 Operating profit (loss) 73,815 25,124 (3,550) (24,843) 70,546 Depreciation, depletion, and amortization 24,437 8,955 5,695 2,029 41,116 Expenditures for long-lived assets 15,520 7,572 1,045 2,391 26,528 Total Assets 442,885 214,961 78,981 161,603 898,430 2018 Net sales $ 500,590 $ 586,643 $ 120,582 $ — $ 1,207,815 Intersegment sales 37 50,460 — — 50,497 Operating profit (loss) 60,008 16,732 10,707 (25,695) 61,752 Depreciation, depletion, and amortization 17,434 8,575 7,066 2,449 35,524 Expenditures for long-lived assets 15,396 15,523 1,983 1,358 34,260 Total Assets 453,345 206,393 90,537 93,035 843,310 Intersegment sales are eliminated in consolidation.
Reconciliation of Operating Profit (Loss) from Segments to Consolidated	A reconciliation of total segment operating profit to total consolidated income before income taxes is as follows: (Thousands) 2020 2019 2018 Total operating profit for reportable segments 8,215 70,546 61,752 Other non-operating (income) expense - net (3,939) 3,431 42,683 Interest expense - net 3,879 1,579 2,471 Income before income taxes $ 8,275 $ 65,536 $ 16,598
Sales and long-lived assets attributed to countries based upon the location of customers	Other geographic information includes the following: (Thousands) 2020 2019 2018 Net sales United States $ 641,727 $ 743,345 $ 726,881 Asia 329,968 256,114 270,672 Europe 189,281 169,132 186,081 All other 15,298 16,833 24,181 Total $ 1,176,274 $ 1,185,424 $ 1,207,815 Property, plant, and equipment, net by country deployed United States $ 223,340 $ 194,596 $ 215,395 All other 86,346 37,680 35,623 Total $ 309,686 $ 232,276 $ 251,018
Disaggregation of Revenue	The following table disaggregates revenue for each segment by end market for 2020 and 2019: (Thousands) Performance Alloys and Composites Advanced Materials Precision Optics Other Total 2020 End Market Semiconductor $ 4,626 $ 526,553 $ 456 $ — $ 531,635 Industrial 90,884 38,052 18,096 — 147,032 Aerospace and Defense 67,173 6,241 19,539 — 92,953 Consumer Electronics 47,983 479 21,566 — 70,028 Automotive 66,489 6,262 3,532 — 76,283 Energy 20,587 75,768 — — 96,355 Telecom and Data Center 44,313 2,183 — — 46,496 Other 52,140 15,329 48,023 — 115,492 Total $ 394,195 $ 670,867 $ 111,212 $ — $ 1,176,274 2019 End Market Semiconductor $ 5,353 $ 432,658 $ 711 $ — $ 438,722 Industrial 106,334 29,917 14,253 — 150,504 Aerospace and Defense 109,717 5,647 20,731 — 136,095 Consumer Electronics 72,360 1,254 18,201 — 91,815 Automotive 69,057 8,179 969 — 78,205 Energy 41,101 74,613 — — 115,714 Telecom and Data Center 61,344 2,981 — — 64,325 Other 34,935 18,514 56,595 — 110,044 Total $ 500,201 $ 573,763 $ 111,460 $ — $ 1,185,424

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Contract with Customer, Asset and Liability	The timing of revenue recognition, billings, and cash collections resulted in the following contract assets and contract liabilities: (Thousands) December 31, 2020 December 31, 2019 $ change % change Accounts receivable, trade $ 156,821 $ 141,168 $ 15,653 11 % Unbilled receivables 8,832 13,583 (4,751) (35) % Unearned revenue 7,713 3,380 4,333 128 %

Restructuring (Tables)

Restructuring (Tables)	12 Months Ended
	Dec. 31, 2020
Restructuring and Related Activities [Abstract]
Restructuring	These costs are presented in the Company's segment results as follows: (Thousands) 2020 2019 2018 Performance Alloys and Composites $ 8,763 $ — $ — Advanced Materials — — 5,599 Precision Optics 2,052 328 — Other 422 457 — Total $ 11,237 $ 785 $ 5,599

Other-net (Tables)

Other-net (Tables)	12 Months Ended
	Dec. 31, 2020
Other-net [Abstract]
Summary of other-net expense	Other-net is summarized for 2020, 2019, and 2018 as follows: (Income) Expense (Thousands) 2020 2019 2018 Metal consignment fees $ 8,587 $ 9,247 $ 10,999 Amortization of intangible assets 2,377 1,400 2,265 Foreign currency (gain) loss (2,569) 666 1,487 Net loss on disposal of fixed assets 466 344 518 Rental income — (87) (416) Other items (398) 213 481 Total other-net $ 8,463 $ 11,783 $ 15,334

Interest (Tables)

Interest (Tables)	12 Months Ended
	Dec. 31, 2020
Interest [Abstract]
Summary of interest incurred, capitalized and paid	The following chart summarizes the interest incurred, capitalized, and paid for 2020, 2019, and 2018: (Thousands) 2020 2019 2018 Interest incurred, net $ 3,889 $ 1,641 $ 2,870 Less: Capitalized interest 10 62 399 Total net expense $ 3,879 $ 1,579 $ 2,471 Interest paid $ 3,442 $ 1,799 $ 1,436

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income tax expenses benefit	Income before income taxes and income tax expense (benefit) are comprised of the following: (Thousands) 2020 2019 2018 Income (loss) before income taxes: Domestic $ (1,153) $ 60,271 $ 20,528 Foreign 9,428 5,265 (3,930) Total income before income taxes $ 8,275 $ 65,536 $ 16,598 Income tax expense: Current income tax expense (benefit): Domestic $ 812 $ 6,995 $ (5,244) Foreign 1,851 1,202 2,710 Total current $ 2,663 $ 8,197 $ (2,534) Deferred income tax (benefit) expense: Domestic $ (5,641) $ 2,687 $ (4,677) Foreign (4,209) 1,258 2,765 Total deferred $ (9,850) $ 3,945 $ (1,912) Total income tax (benefit) expense $ (7,187) $ 12,142 $ (4,446)
Effective income tax rate reconciliation	A reconciliation of the U.S. federal statutory income tax rate to the Company's effective income tax rate is as follows: 2020 2019 2018 U.S. federal statutory rate 21.0 % 21.0 % 21.0 % State and local income taxes, net of federal tax effect (10.0) 1.0 0.2 Effect of excess of percentage depletion over cost depletion (43.0) (4.3) (17.5) Manufacturing production deduction, including impact of NOL carryback — — 6.2 Foreign derived intangible income deduction (1.8) (3.0) (2.8) Non-deductible goodwill impairment 7.1 1.1 — Tax Cuts and Jobs Act impact — 2.3 (66.7) Research and development tax credit (16.4) (1.1) (7.5) Foreign tax credit — (0.3) (1.9) Impact of foreign operations (5.3) 0.9 1.8 Non-deductible transaction costs 6.9 0.2 1.3 Interest from tax authorities (3.8) — — Adjustment to unrecognized tax benefits 1.8 0.2 2.7 Equity compensation (5.3) (3.2) (4.3) Non-deductible officers' compensation 6.8 0.8 — Valuation allowance (45.5) 2.1 38.1 Other items 0.6 0.8 2.6 Effective tax rate (86.9) % 18.5 % (26.8) %
Deferred tax assets and liabilities	Deferred tax assets and (liabilities) recorded in the Consolidated Balance Sheets consist of the following: December 31, (Thousands) 2020 2019 Asset (liability) Post-employment benefits other than pensions $ 1,564 $ 1,626 Other reserves 226 543 Deferred compensation 3,322 3,314 Environmental reserves 1,301 1,384 Lease liabilities 10,469 4,614 Pensions 7,456 5,149 Accrued compensation expense 2,683 5,364 Net operating loss and credit carryforwards 12,685 13,513 Research and development tax credit carryforward 26 25 Subtotal 39,732 35,532 Valuation allowance (14,134) (17,676) Total deferred tax assets 25,598 17,856 Depreciation (12,112) (10,780) Lease assets (10,261) (4,428) Inventory (3,532) (7,954) Amortization (10,754) (2,426) Mine development (1,669) (3,706) Total deferred tax liabilities (38,328) (29,294) Net deferred tax liabilities $ (12,730) $ (11,438)
Reconciliation of unrecognized tax benefits	A reconciliation of the Company’s unrecognized tax benefits (excluding interest and penalties) for the year-to-date periods ended December 31, 2020 and 2019 is as follows: (Thousands) 2020 2019 Balance at January 1 $ 3,221 $ 2,883 Additions to tax provisions related to the current year 191 — Additions to tax positions related to prior years — 399 Reduction to tax positions related to prior years (349) — Lapses on statutes of limitations (703) (61) Balance at December 31 $ 2,360 $ 3,221

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Computation of basic and diluted net earnings per share	The following table sets forth the computation of basic and diluted EPS: (Thousands except per share amounts) 2020 2019* 2018* Numerator for basic and diluted EPS: Net income $ 15,462 $ 53,394 $ 21,044 Denominator: Denominator for basic EPS: Weighted-average shares outstanding 20,338 20,365 20,212 Effect of dilutive securities: Stock appreciation rights 39 72 170 Restricted stock units 102 75 85 Performance-based restricted stock units 124 143 146 Diluted potential common shares 265 290 401 Denominator for diluted EPS: Adjusted weighted-average shares outstanding 20,603 20,655 20,613 Basic EPS $ 0.76 $ 2.62 $ 1.04 Diluted EPS $ 0.75 $ 2.59 $ 1.02

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2020
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories in the Consolidated Balance Sheets are summarized as follows: December 31, (Thousands) 2020 2019* Raw materials and supplies $ 42,905 $ 35,612 Work in process 200,741 175,135 Finished goods 7,132 25,506 Inventories, net 250,778 236,253

Property, Plant, and Equipment

Property, Plant, and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Summary of Property, Plant and Equipment	Property, plant, and equipment on the Consolidated Balance Sheets is summarized as follows: December 31, (Thousands) 2020 2019 Land $ 5,686 $ 4,874 Buildings 165,144 150,323 Machinery and equipment 645,195 639,310 Software 43,652 44,652 Construction in progress 69,297 16,699 Allowances for depreciation (662,724) (669,250) Subtotal 266,250 186,608 Finance leases 34,301 26,069 Allowances for depreciation (4,914) (3,569) Subtotal 29,387 22,500 Mineral resources 4,979 4,980 Mine development 30,058 30,058 Allowances for amortization and depletion (20,988) (11,870) Subtotal 14,049 23,168 Property, plant, and equipment — net $ 309,686 $ 232,276

Leasing Arrangements (Tables)

Leasing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Lease, Cost	The components of operating and finance lease cost for 2020 and 2019 were as follows: (Thousands) 2020 2019 Components of lease expense Operating lease cost $ 10,602 $ 9,835 Finance lease cost Amortization of right-of-use assets 1,324 1,414 Interest on lease liabilities 1,021 1,028 Total lease cost $ 12,947 $ 12,277
Schedule of Supplemental Balance Sheet Information Related to Leases	Supplemental balance sheet information related to the Company's operating and finance leases as of December 31, 2020 and 2019 was as follows: (Thousands, except lease term and discount rate) 2020 2019 Supplemental balance sheet information Operating Leases Operating lease right-of-use assets $ 62,089 $ 23,413 Other liabilities and accrued items 6,908 6,542 Operating lease liabilities 56,761 18,091 Finance Leases Property, plant, and equipment $ 34,301 $ 26,069 Allowances for depreciation, depletion, and amortization (4,914) (3,570) Finance lease assets, net $ 29,387 $ 22,499 Other liabilities and accrued items $ 2,925 $ 1,265 Finance lease liabilities 20,539 17,424 Total principal payable on finance leases $ 23,464 $ 18,689 Weighted Average Remaining Lease Term Operating leases 12.72 4.69 Finance leases 16.59 19.47 Weighted Average Discount Rate Operating leases 6.46% 5.91% Finance leases 4.88% 5.31%
Future estimated minimum payments under capital leases and non-cancelable operating leases	Future maturities of the Company's lease liabilities as of December 31, 2020 are as follows: Finance Operating (Thousands) Leases Leases 2021 $ 3,877 $ 10,707 2022 3,827 9,415 2023 2,536 8,750 2024 1,595 6,608 2025 1,432 6,278 2026 and thereafter 21,906 53,041 Total lease payments 35,173 94,799 Less amount of lease payment representing interest 11,709 31,130 Total present value of lease payments $ 23,464 $ 63,669
Schedule Of Supplemental Cash Flow Information Related To Leases	Supplemental cash flow information related to leases was as follows: (Thousands) 2020 2019 Supplemental cash flow information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 16,216 $ 15,841 Operating cash flows from finance leases 1,021 1,028 Financing cash flows from finance leases 2,213 1,200 Right-of-use assets obtained in exchange for lease obligations: Operating leases 43,037 32,534 Finance leases 6,736 3,919

Intangible Assets and Goodwill

Intangible Assets and Goodwill (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of cost, accumulated amortization and net book value of intangible assets	The cost and accumulated amortization of intangible assets subject to amortization as of December 31, 2020 and 2019, is as follows: 2020 2019 (Thousands) Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net Customer relationships $ 81,231 $ (38,773) $ 42,458 $ 39,601 $ (37,692) $ 1,909 Technology 16,915 (13,290) 3,625 13,377 (12,816) 561 Licenses and other 11,457 (4,840) 6,617 4,257 (3,046) 1,211 Total $ 109,603 $ (56,903) $ 52,700 $ 57,235 $ (53,554) $ 3,681
Finite-lived Intangible Assets Amortization Expense	Estimated amortization e xpense for each of the five succeeding years is as follows: Amortization (Thousands) Expense 2021 4,596 2022 4,585 2023 4,565 2024 4,563 2025 4,084
Schedule of Goodwill	The balance of goodwill at December 31, 2020 and 2019 was $144.9 million and $79.0 million, respectively. A summary of changes in goodwill by reportable segment is as follows: (Thousands) Performance Alloys and Composites Advanced Materials Precision Optics Total Balance at December 31, 2018 $ 1,899 $ 50,276 $ 38,482 $ 90,657 Impairment charge — — (11,560) (11,560) Other — (86) — (86) Balance at December 31, 2019 $ 1,899 $ 50,190 $ 26,922 $ 79,011 Acquisition — — 70,577 70,577 Impairment charge — — (9,053) (9,053) Other — 337 4,044 4,381 Balance at December 31, 2020 $ 1,899 50,527 $ 92,490 $ 144,916

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Summary of long-term debt	Long-term debt in the Consolidated Balance Sheets is summarized as follows: December 31, (Thousands) 2020 2019 Borrowings under Credit Agreement with average interest rate of 1.65% at December 31, 2020 $ 34,000 $ — Foreign debt 3,157 — Fixed rate industrial development revenue bonds 1,322 2,218 Total long-term debt outstanding 38,479 2,218 Current portion of long-term debt (1,937) (868) Gross long-term debt 36,542 1,350 Unamortized deferred financing fees — (90) Long-term debt $ 36,542 $ 1,260
Maturities on long-term debt instruments	Maturities on long-term debt instruments as of December 31, 2020 are as follows: (Thousands) 2021 $ 1,937 2022 500 2023 387 2024 34,387 2025 387 2026 and thereafter 881 Total $ 38,479

Pensions and Other Post-Emplo_2

Pensions and Other Post-Employment Benefits (Tables)	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Obligation and funded status of the company's pension and other post-retirement benefit plans	The obligation and funded status of the Company’s pension and other post-employment benefit plans are shown below. The Pension Benefits column aggregates defined benefit pension plans in the U.S., Germany, Liechtenstein, and England, and the U.S. supplemental retirement plans. The Other Benefits column includes the domestic retiree medical and life insurance plan. Pension Benefits Other Benefits (Thousands) 2020 2019 2020 2019 Change in benefit obligation Benefit obligation at beginning of year $ 186,760 $ 170,136 $ 8,681 $ 11,375 Service cost 1,403 5,918 59 67 Interest cost 5,234 6,292 213 399 Net pension curtailments and settlements (609) (12,212) — — Acquisition 30,360 — — — Plan amendments (799) — — — Actuarial loss (gain) 24,259 20,409 224 (2,192) Benefit payments (4,612) (3,170) (989) (981) Foreign currency exchange rate changes and other 4,111 (613) 2 13 Benefit obligation at end of year 246,107 186,760 8,190 8,681 Change in plan assets Fair value of plan assets at beginning of year 174,046 145,046 — — Plan settlements — — — — Acquisition 23,774 — — — Actual return on plan assets 30,330 27,264 — — Employer contributions 614 4,702 — — Employee contributions 498 124 — — Benefit payments from fund (4,720) (2,933) — — Expenses paid from assets (234) (391) — — Foreign currency exchange rate changes and other 1,868 234 — — Fair value of plan assets at end of year 226,176 174,046 — — Funded status at end of year $ (19,931) $ (12,714) $ (8,190) $ (8,681) Amounts recognized in the Consolidated Other assets $ 13,074 $ 11,298 $ — $ — Other liabilities and accrued items (470) (997) (866) (1,012) Retirement and post-employment benefits (32,535) (23,015) (7,324) (7,669) Net amount recognized $ (19,931) $ (12,714) $ (8,190) $ (8,681)
Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year [Table Text Block]	The following amounts are included within accumulated other comprehensive loss at December 31, 2020: Pension Benefits Other Benefits (Thousands) 2020 2019 2020 2019 Amounts recognized in other comprehensive income (before tax) consist of: Net actuarial loss (gain) $ 49,472 $ 48,073 $ (3,973) $ (4,529) Net prior service cost (credit) (799) — (3,552) (5,049) Net amount recognized $ 48,673 $ 48,073 $ (7,525) $ (9,578)
Schedule of Accumulated and Projected Benefit Obligations	The following table provides information regarding the accumulated benefit obligation: Pension Benefits Other Benefits (Thousands) 2020 2019 2020 2019 Additional information Accumulated benefit obligation for all defined benefit pension plans $ 243,953 $ 185,402 $ — $ — For defined benefit pension plans with benefit obligations in excess of plan assets: Aggregate benefit obligation 62,012 25,640 — — Aggregate fair value of plan assets 29,938 3,045 — — For defined benefit pension plans with accumulated benefit obligations in excess of plan assets: Aggregate accumulated benefit obligation 59,858 24,482 — — Aggregate fair value of plan assets 29,938 3,045 — —
Schedule of Net Benefit Costs	The following table summarizes components of net benefit cost: Pension Benefits Other Benefits (Thousands) 2020 2019 2018 2020 2019 2018 Net benefit cost Service cost $ 1,403 $ 5,918 $ 6,953 $ 59 $ 67 $ 111 Interest cost 5,234 6,292 9,554 213 399 396 Expected return on plan assets (9,333) (8,777) (14,231) — — — Amortization of prior service credit — 483 (123) (1,497) (1,497) (1,497) Recognized net actuarial loss (gain) 1,678 3,304 7,171 (332) (93) — Net periodic benefit (credit) cost (1,018) 7,220 9,324 (1,557) (1,124) (990) Net pension curtailments and settlements 94 3,328 41,406 — — — Total net benefit (credit) cost $ (924) $ 10,548 $ 50,730 $ (1,557) $ (1,124) $ (990)
Summary of cumulative net gain (loss) by component, net of tax, within other comprehensive income	The following table summarizes amounts recognized in other comprehensive income (OCI): Pension Benefits Other Benefits (Thousands) 2020 2019 2018 2020 2019 2018 Change in other comprehensive income OCI at beginning of year $ 48,073 $ 65,409 $ 122,802 $ (9,578) $ (8,976) $ (8,020) Increase (decrease) in OCI: Recognized during year — prior service cost (credit) — (3,811) 123 1,497 1,497 1,497 Recognized during year — net actuarial (losses) gains (1,678) (3,304) (7,171) 332 93 — Occurring during year — prior service cost (799) — — — — — Occurring during year — net actuarial losses (gains) 3,146 2,062 (8,997) 224 (2,192) (2,453) Other adjustments (94) (12,212) (41,406) — — — Foreign currency exchange rate changes 25 (71) 58 — — — OCI at end of year $ 48,673 $ 48,073 $ 65,409 $ (7,525) $ (9,578) $ (8,976) Changes in the components of accumulated other comprehensive (loss) income, including amounts reclassified out, for 2020, 2019, and 2018, and the balances in accumulated other comprehensive (loss) income as of December 31, 2020, 2019, and 2018 are as follows: Gains and Losses Pension and Post- Employment Benefits Foreign Currency Translation (Thousands) Foreign Currency Precious Metals Copper Total Total Balance at December 31, 2017 $ 959 $ (196) $ — $ 763 $ (99,592) $ (4,108) $ (102,937) Other comprehensive income (loss) before reclassifications (333) 467 (569) (435) 11,396 (484) 10,477 Amounts reclassified from accumulated other comprehensive income 10 (109) — (99) 46,953 — 46,854 Other comprehensive income (loss) before tax (323) 358 (569) (534) 58,349 (484) 57,331 Deferred taxes on current period activity (627) 83 (128) (672) 13,300 — 12,628 Other comprehensive income (loss) after tax 304 275 (441) 138 45,049 (484) 44,703 Balance at December 31, 2018 $ 1,263 $ 79 $ (441) $ 901 $ (54,543) $ (4,592) $ (58,234) Balance at December 31, 2018 $ 1,263 $ 79 $ (441) $ 901 $ (54,543) $ (4,592) $ (58,234) Other comprehensive income (loss) before reclassifications 108 (1,285) 209 (968) 9,085 (421) 7,696 Amounts reclassified from accumulated other comprehensive income (29) 595 393 959 8,853 — 9,812 Other comprehensive income (loss) before tax 79 (690) 602 (9) 17,938 (421) 17,508 Deferred taxes on current period activity 18 (159) 136 (5) 4,741 — 4,736 Other comprehensive income (loss) after tax 61 (531) 466 (4) 13,197 (421) 12,772 Balance at December 31, 2019 $ 1,324 $ (452) $ 25 $ 897 $ (41,346) $ (5,013) $ (45,462) Balance at December 31, 2019 $ 1,324 $ (452) $ 25 $ 897 $ (41,346) $ (5,013) $ (45,462) Other comprehensive income (loss) before reclassifications (1,268) (1,675) 218 (2,725) (2,721) 9,030 3,584 Amounts reclassified from accumulated other comprehensive income 222 2,041 354 2,617 (57) — 2,560 Other comprehensive income (loss) before tax (1,046) 366 572 (108) (2,778) 9,030 6,144 Deferred taxes on current period activity (241) 84 129 (28) (651) — (679) Other comprehensive income (loss) after tax (805) 282 443 (80) (2,127) 9,030 6,823 Balance at December 31, 2020 $ 519 $ (170) $ 468 $ 817 $ (43,473) $ 4,017 $ (38,639)
Summary of key valuation assumptions	In determining the projected benefit obligation and the net benefit cost, as of a December 31 measurement date, the Company used the following weighted-average assumptions: Pension Benefits Other Benefits 2020 2019 2018 2020 2019 2018 Weighted-average assumptions used to determine benefit obligations at fiscal year end Discount rate 2.14 % 3.12 % 4.07 % 2.45 % 3.20 % 4.11 % Rate of compensation increase 2.22 % 3.00 % 3.87 % 3.00 % 3.00 % 4.00 % Weighted-average assumptions used to determine net cost for the fiscal year Discount rate 8.37 % 4.16 % 3.63 % 3.20 % 4.11 % 3.43 % Expected long-term return on plan assets 5.70 % 6.06 % 6.63 % N/A N/A N/A Rate of compensation increase 2.87 % 2.99 % 3.98 % 3.00 % 4.00 % 4.00 %
Assumed health care trend rates	Assumed health care trend rates at fiscal year end 2020 2019 Health care trend rate assumed for next year 6.00% 6.25% Rate that the trend rate gradually declines to (ultimate trend rate) 5.00% 5.00% Year that the rate reaches the ultimate trend rate 2025 2025
Summary of fair values of the Company's defined benefit pension plan assets	The following tables present the fair values of the Company’s defined benefit pension plan assets as of December 31, 2020 and 2019 by asset category. The Company has some investments that are valued using net asset value (NAV) as the practical expedient and have not been classified in the fair value hierarchy. Refer to Note S for definitions of the fair value hierarchy. December 31, 2020 (Thousands) Total Level 1 Level 2 Level 3 Cash $ 2,204 $ 2,204 $ — $ — Equity securities (a) 49,293 49,293 — — Fixed-income securities (b) 20,375 20,375 — — Other types of investments: Real estate fund (c) 6,105 6,105 — — Total 77,977 77,977 — — Investments measured at NAV: (d) Pooled investment fund (e) 143,503 Multi-strategy hedge funds (f) 4,624 Private equity funds 72 Total assets at fair value $ 226,176 December 31, 2019 (Thousands) Total Level 1 Level 2 Level 3 Cash $ 1,718 $ 1,718 $ — $ — Equity securities (a) 47,722 47,722 — — Fixed-income securities (b) 3,923 3,923 — — Other types of investments: Real estate fund (c) 3,121 3,121 — — Total 56,484 56,484 — — Investments measured at NAV: (d) Pooled investment fund (e) 113,187 Multi-strategy hedge funds (f) 4,277 Private equity funds 98 Total assets at fair value $ 174,046 (a) Equity securities are primarily comprised of corporate stock and mutual funds directly held by the plans. Equity securities are valued using the closing price reported on the active market on which the individual securities are traded. (b) Fixed income securities are primarily comprised of governmental and corporate bonds directly held by the plans. Governmental and corporate bonds are valued using both market observable inputs for similar assets that are traded on an active market and the closing price on the active market on which the individual securities are traded. (c) Includes a mutual fund that typically invests at least 80% of its assets in equity and debt securities of companies in the real estate industry or related industries or in companies which own significant real estate assets at the time of investment. (d) Certain assets that are measured at fair value using the NAV practical expedient have not been classified in the fair value hierarchy. (e) Pooled investment fund consists of various investment types including equity investments covering a range of geographies and including investment managers that hold long and short positions, property investments, and other multi-strategy funds which combine a range of different credit, equity, and macro-orientated ideas and dynamically allocate funds across asset classes. (f) Includes a fund that invests in a broad portfolio of hedge funds.
Estimated Future Benefits payments	The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid: Other Benefits (Thousands) Pension Benefits Gross Benefit Net of 2021 4,987 867 853 2022 5,854 812 800 2023 7,401 746 736 2024 8,689 667 659 2025 8,924 603 596 2026 through 2030 54,116 2,140 2,120

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Summary of cumulative net gain (loss) by component, net of tax, within other comprehensive income	The following table summarizes amounts recognized in other comprehensive income (OCI): Pension Benefits Other Benefits (Thousands) 2020 2019 2018 2020 2019 2018 Change in other comprehensive income OCI at beginning of year $ 48,073 $ 65,409 $ 122,802 $ (9,578) $ (8,976) $ (8,020) Increase (decrease) in OCI: Recognized during year — prior service cost (credit) — (3,811) 123 1,497 1,497 1,497 Recognized during year — net actuarial (losses) gains (1,678) (3,304) (7,171) 332 93 — Occurring during year — prior service cost (799) — — — — — Occurring during year — net actuarial losses (gains) 3,146 2,062 (8,997) 224 (2,192) (2,453) Other adjustments (94) (12,212) (41,406) — — — Foreign currency exchange rate changes 25 (71) 58 — — — OCI at end of year $ 48,673 $ 48,073 $ 65,409 $ (7,525) $ (9,578) $ (8,976) Changes in the components of accumulated other comprehensive (loss) income, including amounts reclassified out, for 2020, 2019, and 2018, and the balances in accumulated other comprehensive (loss) income as of December 31, 2020, 2019, and 2018 are as follows: Gains and Losses Pension and Post- Employment Benefits Foreign Currency Translation (Thousands) Foreign Currency Precious Metals Copper Total Total Balance at December 31, 2017 $ 959 $ (196) $ — $ 763 $ (99,592) $ (4,108) $ (102,937) Other comprehensive income (loss) before reclassifications (333) 467 (569) (435) 11,396 (484) 10,477 Amounts reclassified from accumulated other comprehensive income 10 (109) — (99) 46,953 — 46,854 Other comprehensive income (loss) before tax (323) 358 (569) (534) 58,349 (484) 57,331 Deferred taxes on current period activity (627) 83 (128) (672) 13,300 — 12,628 Other comprehensive income (loss) after tax 304 275 (441) 138 45,049 (484) 44,703 Balance at December 31, 2018 $ 1,263 $ 79 $ (441) $ 901 $ (54,543) $ (4,592) $ (58,234) Balance at December 31, 2018 $ 1,263 $ 79 $ (441) $ 901 $ (54,543) $ (4,592) $ (58,234) Other comprehensive income (loss) before reclassifications 108 (1,285) 209 (968) 9,085 (421) 7,696 Amounts reclassified from accumulated other comprehensive income (29) 595 393 959 8,853 — 9,812 Other comprehensive income (loss) before tax 79 (690) 602 (9) 17,938 (421) 17,508 Deferred taxes on current period activity 18 (159) 136 (5) 4,741 — 4,736 Other comprehensive income (loss) after tax 61 (531) 466 (4) 13,197 (421) 12,772 Balance at December 31, 2019 $ 1,324 $ (452) $ 25 $ 897 $ (41,346) $ (5,013) $ (45,462) Balance at December 31, 2019 $ 1,324 $ (452) $ 25 $ 897 $ (41,346) $ (5,013) $ (45,462) Other comprehensive income (loss) before reclassifications (1,268) (1,675) 218 (2,725) (2,721) 9,030 3,584 Amounts reclassified from accumulated other comprehensive income 222 2,041 354 2,617 (57) — 2,560 Other comprehensive income (loss) before tax (1,046) 366 572 (108) (2,778) 9,030 6,144 Deferred taxes on current period activity (241) 84 129 (28) (651) — (679) Other comprehensive income (loss) after tax (805) 282 443 (80) (2,127) 9,030 6,823 Balance at December 31, 2020 $ 519 $ (170) $ 468 $ 817 $ (43,473) $ 4,017 $ (38,639)

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
SARs/Stock Options Roll Forward	The following table summarizes the Company's SARs activity during 2020: (Shares in thousands) Number of Weighted- Aggregate Weighted- Outstanding at December 31, 2019 250 $ 44.95 Granted 65 50.95 Exercised (29) 40.70 Cancelled (32) 51.43 Outstanding at December 31, 2020 254 46.18 $ 4,454 4.2 Vested and expected to vest as of December 31, 2020 254 46.18 4,454 4.2 Exercisable at December 31, 2020 148 41.00 3,368 3.4
SARs/Stock Options Nonvested Share Activity	A summary of the status and changes of shares subject to SARs and the related average price per share follows: (Shares in thousands) Number of Weighted- Nonvested as of December 31, 2019 178 $ 14.72 Granted 65 13.67 Vested (109) 13.21 Cancelled (28) 15.50 Nonvested as of December 31, 2020 106 $ 15.46
SARS/Stock Options, Valuation Assumptions	The fair value of the SARs was estimated on the grant date using the Black-Scholes pricing model with the following assumptions: 2020 2019 2018 Risk-free interest rate 1.41 % 2.47 % 2.58 % Dividend yield 0.9 % 0.7 % 0.8 % Volatility 31.8 % 31.7 % 31.9 % Expected lives (in years) 4.8 5.2 5.5
Summary of Restricted Stock Activity	The following table summarizes the stock-settled RSU activity during 2020: (Shares in thousands) Number of Weighted- Outstanding at December 31, 2019 145 $ 50.79 Granted 84 51.55 Vested (33) 36.39 Forfeited (35) 53.52 Outstanding at December 31, 2020 161 $ 53.50
Schedule of Share-based Compensation, Performance Based Restricted Stock Unit Activity	The following table summarizes the activity related to equity-based, performance-based RSUs during 2020: (Shares in thousands) Number of Weighted- Outstanding at December 31, 2019 169 $ 52.74 Granted 46 57.65 Vested (63) 30.28 Forfeited (26) 63.59 Outstanding at December 31, 2020 126 $ 63.61

Fair Value Information and De_2

Fair Value Information and Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of fair value information and derivative financial instruments	The following table summarizes the financial instruments measured at fair value in the Consolidated Balance Sheets at December 31, 2020 and 2019: Fair Value Measurements (Thousands) Total Quoted Prices Significant Other December 31, 2020 Financial Assets Deferred compensation investments $ 3,802 $ 3,802 $ — $ — Foreign currency forward contracts 107 — 107 — Precious metal swaps 127 — 127 — Copper swaps 632 — 632 — Total $ 4,668 $ 3,802 $ 866 $ — Financial Liabilities Deferred compensation liability $ 3,802 $ 3,802 $ — $ — Foreign currency forward contracts 1,203 — 1,203 — Precious metal swaps 349 — 349 — Copper swaps 27 — 27 — Total $ 5,381 $ 3,802 $ 1,579 $ — December 31, 2019 Financial Assets Deferred compensation investments $ 3,391 $ 3,391 $ — $ — Foreign currency forward contracts 188 — 188 — Precious metal swaps 35 — 35 — Copper swaps 61 — 61 — Total $ 3,675 $ 3,391 $ 284 $ — Financial Liabilities Deferred compensation liability $ 3,391 $ 3,391 $ — $ — Foreign currency forward contracts 211 — 211 — Precious metal swaps 623 — 623 — Copper swaps 28 — 28 — Total $ 4,253 $ 3,391 $ 862 $ —
Derivatives Not Designated as Hedging Instruments	The following table summarizes the notional amount and the fair value of the Company’s outstanding derivatives not designated as hedging instruments (on a gross basis) and balance sheet classification as of December 31, 2020 and 2019: December 31, 2020 December 31, 2019 (Thousands) Notional Fair Notional Fair Foreign currency forward contracts Prepaid expenses $ 62,012 $ 107 $ 13,734 $ 95 Other liabilities and accrued items 7,695 55 5,757 16
Summary of the notional amount and the fair value of the Company's outstanding derivatives	The following table summarizes the notional amount and the fair value of the Company’s outstanding derivatives designated as cash flow hedges (on a gross basis) and balance sheet classification at December 31, 2020 and 2019: December 31, 2020 December 31, 2019 (Thousands) Notional Fair Notional Fair Prepaid expenses Foreign currency forward contracts - yen $ — $ — $ 1,025 $ 10 Foreign currency forward contracts - euro — — 3,466 83 Precious metal swaps 2,155 127 1,116 34 Copper swaps 6,225 632 1,951 61 8,380 759 7,558 188 Other assets Precious metal swaps — — 157 1 Other liabilities and accrued items Foreign currency forward contracts - yen 2,668 59 2,355 12 Foreign currency forward contracts - euro 17,611 1,089 15,686 183 Precious metal swaps 4,964 349 7,034 618 Copper swaps 2,445 27 1,266 28 27,688 1,524 26,341 841 Other long-term liabilities Precious metal swaps — — 149 5 Total $ 36,068 $ 765 $ 34,205 $ 657
Derivative Instruments, Gain (Loss)	The following table summarizes the pre-tax amounts reclassified from accumulated other comprehensive income relating to the hedging relationship of the Company’s outstanding derivatives designated as cash flow hedges and income statement classification for years ended December 31, 2020 and 2019: (Thousands) 2020 2019 Hedging relationship Line item Foreign currency forward contracts Net sales $ 222 $ (29) Precious metal swaps Cost of sales 2,041 595 Copper swaps Cost of sales 354 393 Total $ 2,617 $ 959

Contingencies and Commitments (

Contingencies and Commitments (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Undiscounted reserve	The undiscounted reserve balance at the beginning of the year, the amounts expensed and paid, and the balance at December 31, 2020 and 2019 are as follows: (Thousands) 2020 2019 Reserve balance at beginning of year $ 5,937 $ 6,521 Expensed 288 482 Paid (749) (1,066) Reserve balance at end of year $ 5,476 $ 5,937 Ending balance recorded in: Other liabilities and accrued items $ 845 $ 982 Other long-term liabilities 4,631 4,955
Schedule of Asset Retirement Obligations	Asset Retirement Obligations The Company has asset retirement obligations related to its mine in Utah, as well as for certain leased facilities where the Company is contractually obligated to restore the facility back to its original condition at the end of the lease. The following represents a roll forward of the Company's asset retirement obligation liabilities for the years ended December 31, 2020 and 2019: (Thousands) 2020 2019 Asset retirement obligation at beginning of period $ 1,421 $ 1,257 Accretion expense 137 164 Change in liability 207 — Asset retirement obligation at end of period $ 1,765 $ 1,421

Quarterly Data (Unaudited) (Tab

Quarterly Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Summary of selected quarterly financial data	The following tables summarize selected quarterly financial data for the years ended December 31, 2020 and 2019: 2020 (Thousands except per share amounts) First Second Third Fourth Total Net sales $ 277,946 $ 271,468 $ 287,171 $ 339,689 $ 1,176,274 Gross margin 44,570 46,955 45,311 55,797 192,633 Percent of net sales 16.0 % 17.3 % 15.8 % 16.4 % 16.4 % Net (loss) income (1) $ (3,878) $ 5,803 $ 5,471 $ 8,066 $ 15,462 Net (loss) income per share of common stock: Basic $ (0.19) $ 0.29 $ 0.27 $ 0.40 0.76 Diluted (2) (0.19) 0.28 0.27 0.39 0.75 2019 First Second Third Fourth Total Net sales $ 301,441 $ 297,843 $ 305,979 $ 280,161 $ 1,185,424 Gross margin 69,606 71,997 66,605 54,482 262,690 Percent of net sales 23.1 % 24.2 % 21.8 % 19.4 % 22.2 % Net income (3) $ 17,133 $ 17,393 $ 4,522 $ 14,346 $ 53,394 Net income per share of common stock: Basic $ 0.85 $ 0.85 $ 0.22 $ 0.70 $ 2.62 Diluted 0.83 0.84 0.22 0.69 2.59

Significant Accounting Polici_4

Significant Accounting Policies Organization (Details)	12 Months Ended
	Dec. 31, 2020Segment
Accounting Policies [Abstract]
Number of Reportable Segments	4

Significant Accounting Polici_5

Significant Accounting Policies Accounts Receivable (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Accounts Receivable, Allowance for Credit Loss, Current	$ 0.5	$ 0.4

Significant Accounting Polici_6

Significant Accounting Policies Property Plant Equipment (Details)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Useful life of lease hold improvements Minimum	Life of lease
Useful life of lease hold improvements Maximum	Life of lease
Minimum | Land improvements
Property, Plant and Equipment [Line Items]
Useful life of class of asset	10 years
Minimum | Buildings
Property, Plant and Equipment [Line Items]
Useful life of class of asset	20 years
Minimum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Useful life of class of asset	3 years
Minimum | Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful life of class of asset	4 years
Minimum | Automobiles and trucks
Property, Plant and Equipment [Line Items]
Useful life of class of asset	3 years
Minimum | Research equipment
Property, Plant and Equipment [Line Items]
Useful life of class of asset	3 years
Minimum | Computer hardware
Property, Plant and Equipment [Line Items]
Useful life of class of asset	3 years
Minimum | Computer software
Property, Plant and Equipment [Line Items]
Useful life of class of asset	3 years
Maximum | Land improvements
Property, Plant and Equipment [Line Items]
Useful life of class of asset	20 years
Maximum | Buildings
Property, Plant and Equipment [Line Items]
Useful life of class of asset	40 years
Maximum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Useful life of class of asset	15 years
Maximum | Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful life of class of asset	10 years
Maximum | Automobiles and trucks
Property, Plant and Equipment [Line Items]
Useful life of class of asset	8 years
Maximum | Research equipment
Property, Plant and Equipment [Line Items]
Useful life of class of asset	10 years
Maximum | Computer hardware
Property, Plant and Equipment [Line Items]
Useful life of class of asset	10 years
Maximum | Computer software
Property, Plant and Equipment [Line Items]
Useful life of class of asset	10 years

Significant Accounting Polici_7

Significant Accounting Policies Mine Development (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Accounting Policies [Abstract]
Cost of Mine Development	$ 12.9

Significant Accounting Polici_8

Significant Accounting Policies Unearned Income (Details) $ in Millions	Dec. 31, 2020USD ($)
Accounting Policies [Abstract]
Deferred Income	$ 58.8

Significant Accounting Polici_9

Significant Accounting Policies Advertising (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Advertising Expense	$ 300	$ 700	$ 1,200

Significant Accounting Polic_10

Significant Accounting Policies Inventory (Details)	Dec. 31, 2020
Accounting Policies [Abstract]
Percentage of LIFO Inventory	45.00%

Summary of Retrospective Applic

Summary of Retrospective Application from LIFO to FIFO (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 25, 2020	Jun. 26, 2020	Mar. 27, 2020	Dec. 31, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cost of sales	$ 283,892	$ 241,860	$ 224,513	$ 233,376	$ 225,679	$ 239,374	$ 225,846	$ 231,835	$ 983,641	$ 922,734	$ 956,454
Gross margin	55,797	45,311	46,955	44,570	54,482	66,605	71,997	69,606	192,633	262,690	251,361
Operating profit (loss)	6,828	(616)	7,571	(5,568)	16,049	7,663	25,153	21,681	8,215	70,546	61,752
Income (loss) before income taxes	6,856	(874)	7,163	(4,870)	15,925	7,100	21,541	20,970	8,275	65,536	16,598
Income tax (benefit) expense	(1,210)	(6,345)	1,360	(992)	1,579	2,578	4,148	3,837	(7,187)	12,142	(4,446)
Net income	$ 8,066	$ 5,471	$ 5,803	$ (3,878)	$ 14,346	$ 4,522	$ 17,393	$ 17,133	$ 15,462	$ 53,394	$ 21,044
Basic EPS (in usd per share)	$ 0.40	$ 0.27	$ 0.29	$ (0.19)	$ 0.70	$ 0.22	$ 0.85	$ 0.85	$ 0.76	$ 2.62	$ 1.04
Diluted EPS (in usd per share)	$ 0.39	$ 0.27	$ 0.28	$ (0.19)	$ 0.69	$ 0.22	$ 0.84	$ 0.83	$ 0.75	$ 2.59	$ 1.02
Comprehensive income									$ 22,285	$ 66,166	$ 65,747
Inventories, net	$ 250,778				$ 236,253				250,778	236,253
Prepaid and other current assets	20,896				21,736				20,896	21,736
Deferred income taxes (liability)	15,864				13,104				15,864	13,104
Retained earnings	631,058				624,954				631,058	624,954
Deferred income tax (benefit) expense									(9,850)	3,945	(1,912)
Decrease (increase) in inventory									(1,288)	20,485	3,978
Decrease (increase) in prepaid and other current assets									2,475	869	1,814
Previously Reported
Net income									16,942	50,660	20,846
Deferred income tax (benefit) expense									(6,940)	2,584	(1,318)
Decrease (increase) in inventory									(3,207)	24,031	4,234
Decrease (increase) in prepaid and other current assets									4	1,418	1,162
Revision of Prior Period, Change in Accounting Principle, Adjustment
Net income									(1,480)	2,734	198
Deferred income tax (benefit) expense									(2,910)	1,361	(594)
Decrease (increase) in inventory									1,919	(3,546)	(256)
Decrease (increase) in prepaid and other current assets									2,471	(549)	652
Previously Reported
Net income									16,942	50,660	20,846
Comprehensive income									23,765	63,432	65,549
Revision of Prior Period, Change in Accounting Principle, Adjustment
Net income									(1,480)	2,734	198
Comprehensive income									(1,480)	2,734	198
Previously Reported
Cost of sales	285,442	$ 240,531	$ 223,378	$ 232,371	225,154	$ 240,748	$ 228,249	$ 232,129	981,722	926,280	956,710
Gross margin	54,247	46,640	48,090	45,575	55,007	65,231	69,594	69,312	194,552	259,144	251,105
Operating profit (loss)	5,278	713	8,706	(4,563)	16,574	6,289	22,750	21,387	10,134	67,000	61,496
Income (loss) before income taxes	5,306	455	8,298	(3,865)	16,450	5,726	19,138	20,676	10,194	61,990	16,342
Income tax (benefit) expense	(1,565)	(6,041)	1,620	(762)	1,699	2,263	3,598	3,770	(6,748)	11,330	(4,504)
Net income	$ 6,871	$ 6,496	$ 6,678	$ (3,103)	$ 14,751	$ 3,463	$ 15,540	$ 16,906	$ 16,942	$ 50,660	$ 20,846
Basic EPS (in usd per share)	$ 0.34	$ 0.32	$ 0.33	$ (0.15)	$ 0.72	$ 0.17	$ 0.76	$ 0.83	$ 0.83	$ 2.49	$ 1.03
Diluted EPS (in usd per share)	$ 0.33	$ 0.32	$ 0.32	$ (0.15)	$ 0.71	$ 0.17	$ 0.75	$ 0.82	$ 0.82	$ 2.45	$ 1.01
Revision of Prior Period, Change in Accounting Principle, Adjustment
Cost of sales	$ (1,550)	$ 1,329	$ 1,135	$ 1,005	$ 525	$ (1,374)	$ (2,403)	$ (294)	$ 1,919	$ (3,546)	$ (256)
Gross margin	1,550	(1,329)	(1,135)	(1,005)	(525)	1,374	2,403	294	(1,919)	3,546	256
Operating profit (loss)	1,550	(1,329)	(1,135)	(1,005)	(525)	1,374	2,403	294	(1,919)	3,546	256
Income (loss) before income taxes	1,550	(1,329)	(1,135)	(1,005)	(525)	1,374	2,403	294	(1,919)	3,546	256
Income tax (benefit) expense	355	(304)	(260)	(230)	(120)	315	550	67	(439)	812	58
Net income	$ 1,195	$ (1,025)	$ (875)	$ (775)	$ (405)	$ 1,059	$ 1,853	$ 227	$ (1,480)	$ 2,734	$ 198
Basic EPS (in usd per share)	$ 0.06	$ (0.05)	$ (0.04)	$ (0.04)	$ (0.02)	$ 0.05	$ 0.09	$ 0.02	$ (0.07)	$ 0.13	$ 0.01
Diluted EPS (in usd per share)	$ 0.06	$ (0.05)	$ (0.04)	$ (0.04)	$ (0.02)	$ 0.05	$ 0.09	$ 0.01	$ (0.07)	$ 0.14	$ 0.01
Previously Reported
Inventories, net	$ 206,834				$ 190,390				$ 206,834	$ 190,390
Prepaid and other current assets	23,470				21,839				23,470	21,839
Deferred income taxes (liability)	8,081				2,410				8,081	2,410
Retained earnings	597,471				589,888				597,471	589,888
Revision of Prior Period, Change in Accounting Principle, Adjustment
Inventories, net	43,944				45,863				43,944	45,863
Prepaid and other current assets	(2,574)				(103)				(2,574)	(103)
Deferred income taxes (liability)	7,783				10,694				7,783	10,694
Retained earnings	$ 33,587				$ 35,066				$ 33,587	$ 35,066

Acquisition (Details)

Acquisition (Details) - USD ($)	Jul. 17, 2020	Dec. 31, 2020	Jun. 26, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Combinations [Abstract]
Business combination, consideration transferred	$ 136,100,000
Long-term debt	22,500,000
Borrowings under Credit Agreement with average interest rate of 1.65% at December 31, 2020		$ 34,000,000	$ 150,000,000	$ 0
Business combination, integration related costs		6,500,000
Business Acquisition [Line Items]
Goodwill		$ 144,916,000		$ 79,011,000	$ 90,657,000
Optics Balzers [Member]
Business Combinations [Abstract]
Long-term debt	21,926,000
Business Acquisition [Line Items]
Goodwill	$ 70,639,000

Acquisition (Details 1)

Acquisition (Details 1) - USD ($) $ in Thousands	Dec. 31, 2020	Jul. 17, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets
Operating lease, right-of-use assets	$ 62,089		$ 23,413
Goodwill	$ 144,916		$ 79,011	$ 90,657
Liabilities
Long-term debt		$ 22,500
Optics Balzers [Member]
Assets
Cash and cash equivalents		5,390
Accounts receivable		8,484
Inventories		10,715
Prepaid and other current assets		937
Property, plant, and equipment		46,791
Operating lease, right-of-use assets		13,357
Intangible assets		49,300
Goodwill		70,639
Total assets acquired		205,613
Liabilities
Short-term debt		600
Accounts payable		2,851
Salaries and wages		4,392
Other liabilities and accrued items		3,678
Income taxes		61
Unearned revenue		1,259
Other long-term liabilities		207
Operating lease liabilities		12,356
Finance lease liabilities		2,642
Retirement and post-employment benefits		6,586
Unearned income		1,835
Long-term income taxes		181
Deferred income taxes		10,934
Long-term debt		21,926
Total liabilities assumed		69,508
Net assets acquired		$ 136,105

Acquisition (Details 2)

Acquisition (Details 2) - Optics Balzers [Member] $ in Thousands	Jul. 17, 2020USD ($)
Acquired Indefinite-lived Intangible Assets [Line Items]
Intangible assets	$ 49,300
Customer Relationships
Acquired Indefinite-lived Intangible Assets [Line Items]
Intangible assets	$ 40,141
Acquired finite-lived intangible assets, weighted average useful life	18 years
Technology
Acquired Indefinite-lived Intangible Assets [Line Items]
Intangible assets	$ 4,059
Acquired finite-lived intangible assets, weighted average useful life	5 years
License
Acquired Indefinite-lived Intangible Assets [Line Items]
Intangible assets	$ 5,100
Acquired finite-lived intangible assets, weighted average useful life	5 years

Segment Reporting and Geograp_3

Segment Reporting and Geographic Information (Details 1) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 25, 2020	Jun. 26, 2020	Mar. 27, 2020	Dec. 31, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Net sales	$ 339,689	$ 287,171	$ 271,468	$ 277,946	$ 280,161	$ 305,979	$ 297,843	$ 301,441	$ 1,176,274	$ 1,185,424	$ 1,207,815
Operating profit (loss)	6,828	$ (616)	$ 7,571	$ (5,568)	16,049	$ 7,663	$ 25,153	$ 21,681	8,215	70,546	61,752
Depreciation, depletion, and amortization									42,384	41,116	35,524
Expenditures for long-lived assets									67,274	26,528	34,260
Total Assets	1,057,860				898,430				1,057,860	898,430	843,310
Performance Alloys and Composites
Segment Reporting Information [Line Items]
Net sales									394,195	500,201
Operating profit (loss)									13,597	73,815	60,008
Depreciation, depletion, and amortization									25,782	24,437	17,434
Expenditures for long-lived assets									53,841	15,520	15,396
Total Assets	477,892				442,885				477,892	442,885	453,345
Advanced Materials
Segment Reporting Information [Line Items]
Net sales									670,867	573,763
Operating profit (loss)									22,120	25,124	16,732
Depreciation, depletion, and amortization									8,061	8,955	8,575
Expenditures for long-lived assets									9,003	7,572	15,523
Total Assets	251,637				214,961				251,637	214,961	206,393
Precision Optics
Segment Reporting Information [Line Items]
Net sales									111,212	111,460
Operating profit (loss)									(4,382)	(3,550)	10,707
Depreciation, depletion, and amortization									6,564	5,695	7,066
Expenditures for long-lived assets									908	1,045	1,983
Total Assets	268,004				78,981				268,004	78,981	90,537
Other
Segment Reporting Information [Line Items]
Net sales									0	0
Operating profit (loss)									(23,120)	(24,843)	(25,695)
Depreciation, depletion, and amortization									1,977	2,029	2,449
Expenditures for long-lived assets									3,522	2,391	1,358
Total Assets	$ 60,327				$ 161,603				60,327	161,603	93,035
Operating Segments
Segment Reporting Information [Line Items]
Net sales									1,176,274	1,185,424	1,207,815
Operating Segments | Performance Alloys and Composites
Segment Reporting Information [Line Items]
Net sales									394,195	500,201	500,590
Operating Segments | Advanced Materials
Segment Reporting Information [Line Items]
Net sales									670,867	573,763	586,643
Operating Segments | Precision Optics
Segment Reporting Information [Line Items]
Net sales									111,212	111,460	120,582
Operating Segments | Other
Segment Reporting Information [Line Items]
Net sales									0	0	0
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales									35,918	70,085	50,497
Intersegment Eliminations | Performance Alloys and Composites
Segment Reporting Information [Line Items]
Net sales									6	38	37
Intersegment Eliminations | Advanced Materials
Segment Reporting Information [Line Items]
Net sales									35,912	70,047	50,460
Intersegment Eliminations | Precision Optics
Segment Reporting Information [Line Items]
Net sales									0	0	0
Intersegment Eliminations | Other
Segment Reporting Information [Line Items]
Net sales									$ 0	$ 0	$ 0

Segment Reporting and Geograp_4

Segment Reporting and Geographic Information (Details 2) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 25, 2020	Jun. 26, 2020	Mar. 27, 2020	Dec. 31, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting [Abstract]
Total operating profit for reportable segments	$ 6,828	$ (616)	$ 7,571	$ (5,568)	$ 16,049	$ 7,663	$ 25,153	$ 21,681	$ 8,215	$ 70,546	$ 61,752
Other non-operating (income) expense-net									(3,939)	3,431	42,683
Interest expense - net									3,879	1,579	2,471
Income before income taxes	$ 6,856	$ (874)	$ 7,163	$ (4,870)	$ 15,925	$ 7,100	$ 21,541	$ 20,970	$ 8,275	$ 65,536	$ 16,598

Segment Reporting and Geograp_5

Segment Reporting and Geographic Information (Details 3) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 25, 2020	Jun. 26, 2020	Mar. 27, 2020	Dec. 31, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Sales and long-lived assets attributed to countries based upon the location of customers
Net sales	$ 339,689	$ 287,171	$ 271,468	$ 277,946	$ 280,161	$ 305,979	$ 297,843	$ 301,441	$ 1,176,274	$ 1,185,424	$ 1,207,815
Property, plant, and equipment — net	309,686				232,276				309,686	232,276	251,018
United States
Sales and long-lived assets attributed to countries based upon the location of customers
Net sales									641,727	743,345	726,881
Property, plant, and equipment — net	223,340				194,596				223,340	194,596	215,395
Asia
Sales and long-lived assets attributed to countries based upon the location of customers
Net sales									329,968	256,114	270,672
Europe
Sales and long-lived assets attributed to countries based upon the location of customers
Net sales									189,281	169,132	186,081
All other
Sales and long-lived assets attributed to countries based upon the location of customers
Net sales									15,298	16,833	24,181
Property, plant, and equipment — net	$ 86,346				$ 37,680				$ 86,346	$ 37,680	$ 35,623

Segment Reporting and Geograp_6

Segment Reporting and Geographic Information (Details 4) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 25, 2020	Jun. 26, 2020	Mar. 27, 2020	Dec. 31, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 339,689	$ 287,171	$ 271,468	$ 277,946	$ 280,161	$ 305,979	$ 297,843	$ 301,441	$ 1,176,274	$ 1,185,424	$ 1,207,815
Semiconductor
Disaggregation of Revenue [Line Items]
Net sales									531,635	438,722
Industrial
Disaggregation of Revenue [Line Items]
Net sales									147,032	150,504
Aerospace and Defense
Disaggregation of Revenue [Line Items]
Net sales									92,953	136,095
Consumer Electronics
Disaggregation of Revenue [Line Items]
Net sales									70,028	91,815
Automotive
Disaggregation of Revenue [Line Items]
Net sales									76,283	78,205
Energy
Disaggregation of Revenue [Line Items]
Net sales									96,355	115,714
Telecomm and Data Center
Disaggregation of Revenue [Line Items]
Net sales									46,496	64,325
Other End Market
Disaggregation of Revenue [Line Items]
Net sales									115,492	110,044
Performance Alloys and Composites
Disaggregation of Revenue [Line Items]
Net sales									394,195	500,201
Performance Alloys and Composites | Semiconductor
Disaggregation of Revenue [Line Items]
Net sales									4,626	5,353
Performance Alloys and Composites | Industrial
Disaggregation of Revenue [Line Items]
Net sales									90,884	106,334
Performance Alloys and Composites | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Net sales									67,173	109,717
Performance Alloys and Composites | Consumer Electronics
Disaggregation of Revenue [Line Items]
Net sales									47,983	72,360
Performance Alloys and Composites | Automotive
Disaggregation of Revenue [Line Items]
Net sales									66,489	69,057
Performance Alloys and Composites | Energy
Disaggregation of Revenue [Line Items]
Net sales									20,587	41,101
Performance Alloys and Composites | Telecomm and Data Center
Disaggregation of Revenue [Line Items]
Net sales									44,313	61,344
Performance Alloys and Composites | Other End Market
Disaggregation of Revenue [Line Items]
Net sales									52,140	34,935
Advanced Materials
Disaggregation of Revenue [Line Items]
Net sales									670,867	573,763
Advanced Materials | Semiconductor
Disaggregation of Revenue [Line Items]
Net sales									526,553	432,658
Advanced Materials | Industrial
Disaggregation of Revenue [Line Items]
Net sales									38,052	29,917
Advanced Materials | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Net sales									6,241	5,647
Advanced Materials | Consumer Electronics
Disaggregation of Revenue [Line Items]
Net sales									479	1,254
Advanced Materials | Automotive
Disaggregation of Revenue [Line Items]
Net sales									6,262	8,179
Advanced Materials | Energy
Disaggregation of Revenue [Line Items]
Net sales									75,768	74,613
Advanced Materials | Telecomm and Data Center
Disaggregation of Revenue [Line Items]
Net sales									2,183	2,981
Advanced Materials | Other End Market
Disaggregation of Revenue [Line Items]
Net sales									15,329	18,514
Precision Optics
Disaggregation of Revenue [Line Items]
Net sales									111,212	111,460
Precision Optics | Semiconductor
Disaggregation of Revenue [Line Items]
Net sales									456	711
Precision Optics | Industrial
Disaggregation of Revenue [Line Items]
Net sales									18,096	14,253
Precision Optics | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Net sales									19,539	20,731
Precision Optics | Consumer Electronics
Disaggregation of Revenue [Line Items]
Net sales									21,566	18,201
Precision Optics | Automotive
Disaggregation of Revenue [Line Items]
Net sales									3,532	969
Precision Optics | Energy
Disaggregation of Revenue [Line Items]
Net sales									0	0
Precision Optics | Telecomm and Data Center
Disaggregation of Revenue [Line Items]
Net sales									0	0
Precision Optics | Other End Market
Disaggregation of Revenue [Line Items]
Net sales									48,023	56,595
Other
Disaggregation of Revenue [Line Items]
Net sales									0	0
Other | Semiconductor
Disaggregation of Revenue [Line Items]
Net sales									0	0
Other | Industrial
Disaggregation of Revenue [Line Items]
Net sales									0	0
Other | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Net sales									0	0
Other | Consumer Electronics
Disaggregation of Revenue [Line Items]
Net sales									0	0
Other | Automotive
Disaggregation of Revenue [Line Items]
Net sales									0	0
Other | Energy
Disaggregation of Revenue [Line Items]
Net sales									0	0
Other | Telecomm and Data Center
Disaggregation of Revenue [Line Items]
Net sales									0	0
Other | Other End Market
Disaggregation of Revenue [Line Items]
Net sales									$ 0	$ 0

Segment Reporting and Geograp_7

Segment Reporting and Geographic Information (Details Textual)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting [Abstract]
Percentage of customers accounted for the company's sale	10.00%	10.00%	10.00%

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Capitalized Contract Cost [Line Items]
Change in Unearned revenue	$ 2,935	$ (2,538)	$ 477
Trade Accounts Receivable [Member]
Capitalized Contract Cost [Line Items]
Contract with Customer, Asset	156,821	141,168
Change in Accounts receivable, trade	$ 15,653
Contract Asset Percent Change	11.00%
Unbilled Receivables [Member]
Capitalized Contract Cost [Line Items]
Contract with Customer, Asset	$ 8,832	13,583
Change in Unbilled receivables	$ (4,751)
Contract Asset Percent Change	(35.00%)
Unearned Revenue [Member]
Capitalized Contract Cost [Line Items]
Unearned revenue	$ 7,713	$ 3,380
Change in Unearned revenue	$ 4,333
Contract Liability Percent Change	128.00%

Revenue Recognition Textuals (D

Revenue Recognition Textuals (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Revenue from Contract with Customer [Abstract]
Deferred Revenue, Revenue Recognized	$ 3.2
Remaining Performance Obligation	$ 10.2

Restructuring (Details)

Restructuring (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 11,237	$ 785	$ 5,599
Performance Alloys and Composites
Restructuring Cost and Reserve [Line Items]
Restructuring expense	8,763	0	0
Advanced Materials
Restructuring Cost and Reserve [Line Items]
Restructuring expense	0	0	5,599
Precision Optics
Restructuring Cost and Reserve [Line Items]
Restructuring expense	2,052	328	0
Other
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 422	$ 457	$ 0

Restructuring Textual (Details)

Restructuring Textual (Details)	3 Months Ended		12 Months Ended
	Mar. 27, 2020USD ($)	Sep. 27, 2019USD ($)	Dec. 31, 2020USD ($)Employee	Dec. 31, 2019USD ($)Employee	Dec. 31, 2018USD ($)Employee
Restructuring Cost and Reserve [Line Items]
Goodwill impairment charges			$ 9,053,000	$ 11,560,000	$ 0
Asset impairment charges	$ 10,800,000	$ 14,100,000	10,472,000	14,141,000	0
Property, plant and equipment held for sale			200,000
Restructuring expense			11,237,000	785,000	5,599,000
Other
Restructuring Cost and Reserve [Line Items]
Restructuring expense			422,000	$ 457,000	0
Number of positions eliminated | Employee				7
Advanced Materials
Restructuring Cost and Reserve [Line Items]
Goodwill impairment charges			0	$ 0	0
Restructuring expense			0	0	$ 5,599,000
Number of positions eliminated | Employee					40
Remaining severance payments					$ 300,000
Performance Alloys and Composites
Restructuring Cost and Reserve [Line Items]
Goodwill impairment charges			0	0	0
Restructuring expense			8,763,000	0	0
Severance costs			$ 2,100,000
Number of positions eliminated | Employee			63
Other restructuring costs			$ 5,300,000
Remaining severance payments			500,000
Remaining facility costs			500,000
Precision Optics
Restructuring Cost and Reserve [Line Items]
Goodwill impairment charges			9,053,000	11,560,000	0
Asset impairment charges			1,400,000
Restructuring expense			2,052,000	$ 328,000	$ 0
Severance costs			$ 400,000
Number of positions eliminated | Employee			28
Number of positions eliminated | Employee				19
Precision Optics | LAC Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring expense			$ 1,700,000
Severance costs			$ 700,000
Number of positions eliminated | Employee			20
Other restructuring costs			$ 1,000,000
Remaining severance payments			600,000
Remaining facility costs			1,000,000
Restructuring cost, expected			$ 200,000

Other-net (Details)

Other-net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary of other-net expense
Metal consignment fees	$ 8,587	$ 9,247	$ 10,999
Amortization of intangible assets	2,377	1,400	2,265
Foreign currency loss (gain)	(2,569)	666	1,487
Net loss on disposal of fixed assets	466	344	518
Rental Income	0	(87)	(416)
Other items	(398)	213	481
Total	$ 8,463	$ 11,783	$ 15,334

Interest (Details)

Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary of interest incurred, capitalized and paid
Interest incurred, net	$ 3,889	$ 1,641	$ 2,870
Less: Capitalized interest	10	62	399
Total net expense	3,879	1,579	2,471
Interest paid	$ 3,442	$ 1,799	$ 1,436

Interest (Details Textual)

Interest (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest [Abstract]
Amortization of deferred financing costs	$ 790	$ 962	$ 1,009

Income Taxes Textuals 1 (Detail

Income Taxes Textuals 1 (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Income Tax Disclosure [Abstract]
Tax Cuts and Jobs Act of 2017, Complete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit)	$ 11.1
Tax Cuts and Jobs Act Change in Tax Rate, Deferred Tax Asset (Liability), Income Tax Expense (Credit)	2.8
Tax Cuts and Jobs Act, Transition Tax, Income Tax Expense (Credit)	1.2
Tax Cuts and Jobs Act, Valuation Allowance Reversal, Tax Benefit	$ 7.1

Income Taxes Table 1 (Details)

Income Taxes Table 1 (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 25, 2020	Jun. 26, 2020	Mar. 27, 2020	Dec. 31, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income (loss) before income taxes:
Domestic									$ (1,153)	$ 60,271	$ 20,528
Foreign									9,428	5,265	(3,930)
Income before income taxes	$ 6,856	$ (874)	$ 7,163	$ (4,870)	$ 15,925	$ 7,100	$ 21,541	$ 20,970	8,275	65,536	16,598
Current income tax expense (benefit):
Domestic									812	6,995	(5,244)
Foreign									1,851	1,202	2,710
Total current									2,663	8,197	(2,534)
Deferred income tax (benefit) expense:
Domestic									(5,641)	2,687	(4,677)
Foreign									(4,209)	1,258	2,765
Total deferred									(9,850)	3,945	(1,912)
Total income tax (benefit) expense	$ (1,210)	$ (6,345)	$ 1,360	$ (992)	$ 1,579	$ 2,578	$ 4,148	$ 3,837	$ (7,187)	$ 12,142	$ (4,446)

Income Taxes Table 2 (Details)

Income Taxes Table 2 (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of the federal statutory and effective income tax rate
U.S. Federal statutory rate	21.00%	21.00%	21.00%
State and local income taxes, net of federal tax effect	(10.00%)	1.00%	0.20%
Effect of excess of percentage depletion over cost depletion	(43.00%)	(4.30%)	(17.50%)
Manufacturing production deduction, including impact of NOL carryback	0.00%	0.00%	6.20%
Foreign Derived Intangible Income Tax Deduction	(1.80%)	(3.00%)	(2.80%)
Non-deductible goodwill impairment	7.10%	1.10%	0.00%
Tax Cuts and Jobs Act Impact	0.00%	2.30%	(66.70%)
Research and developmental tax credit	(16.40%)	(1.10%)	(7.50%)
Foreign Tax Credit	0.00%	(0.30%)	(1.90%)
Impact of foreign operations	(5.30%)	0.90%	1.80%
Non-deductible transaction costs	6.90%	0.20%	1.30%
Effective Income Tax Rate Reconciliation, Deduction, Percent	(3.80%)	0.00%	0.00%
Adjustment to unrecognized tax benefits	1.80%	0.20%	2.70%
Equity compensation	(5.30%)	(3.20%)	(4.30%)
Non-deductible officers' compensation	6.80%	0.80%	0.00%
Valuation allowance	(45.50%)	2.10%	38.10%
Other items	0.60%	0.80%	2.60%
Effective tax rate	(86.90%)	18.50%	(26.80%)

Income Taxes Table 3 (Details)

Income Taxes Table 3 (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Asset (liability)
Post-employment benefits other than pensions	$ 1,564	$ 1,626
Other reserves	226	543
Deferred compensation	3,322	3,314
Environmental reserves	1,301	1,384
Lease liabilities	10,469	4,614
Pensions	7,456	5,149
Accrued compensation expense	2,683	5,364
Net operating loss and credit carryforwards	12,685	13,513
Research and development tax credit carryforward	26	25
Subtotal	39,732	35,532
Valuation allowance	(14,134)	(17,676)
Total deferred tax assets	25,598	17,856
Depreciation	(12,112)	(10,780)
Lease assets	(10,261)	(4,428)
Inventory	(3,532)	(7,954)
Amortization	(10,754)	(2,426)
Mine development	(1,669)	(3,706)
Total deferred tax liabilities	(38,328)	(29,294)
Net deferred tax liabilities	$ (12,730)	$ (11,438)

Income Taxes Textuals 2 (Detail

Income Taxes Textuals 2 (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)$ / shares
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Valuation Allowance	$ 9,500
Income Tax Holiday, Aggregate Dollar Amount	$ 500
Income Tax Holiday, Income Tax Benefits Per Share | $ / shares	$ 0.03
Foreign Country [Member]
Operating Loss Carryforwards [Line Items]
Foreign net operating loss carryforwards, do not expire	$ 27,800
Foreign net operating loss carryforwards subject to expiration	7,100
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Foreign net operating loss carryforwards subject to expiration	20,500
Tax Credit, amount subject to expiration	$ 3,700

Income Taxes Table 4 (Details)

Income Taxes Table 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of unrecognized tax benefits
Balance at January 1	$ 3,221	$ 2,883
Additions to tax provisions related to the current year	191	0
Additions to tax positions related to prior years	0	399
Reduction to tax positions related to prior years	(349)	0
Lapses on statutes of limitations	(703)	(61)
Balance at December 31	$ 2,360	$ 3,221

Income Taxes Textuals 3 (Detail

Income Taxes Textuals 3 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate if Recognized	$ 2,700	$ 2,400
Income Taxes Paid	3,900	9,300	$ 2,600
Unrepatriated Earnings	98,400
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	703	$ 61
Domestic Tax Authority [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	$ 1,600

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 25, 2020	Jun. 26, 2020	Mar. 27, 2020	Dec. 31, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator for basic and diluted EPS:
Net income	$ 8,066	$ 5,471	$ 5,803	$ (3,878)	$ 14,346	$ 4,522	$ 17,393	$ 17,133	$ 15,462	$ 53,394	$ 21,044
Denominator for basic EPS:
Weighted-average shares outstanding									20,338	20,365	20,212
Effect of dilutive securities:
Diluted potential common shares (in shares)									265	290	401
Denominator for diluted EPS:
Adjusted weighted-average shares outstanding									20,603	20,655	20,613
Basic EPS (in usd per share)	$ 0.40	$ 0.27	$ 0.29	$ (0.19)	$ 0.70	$ 0.22	$ 0.85	$ 0.85	$ 0.76	$ 2.62	$ 1.04
Diluted EPS (in usd per share)	$ 0.39	$ 0.27	$ 0.28	$ (0.19)	$ 0.69	$ 0.22	$ 0.84	$ 0.83	$ 0.75	$ 2.59	$ 1.02
Retained Earnings [Member]
Numerator for basic and diluted EPS:
Net income									$ 15,462	$ 53,394	$ 21,044
Stock Appreciation Rights (SARs)
Effect of dilutive securities:
Dilutive effect of share-based compensation (in shares)									39	72	170
Restricted Stock Units (RSUs)
Effect of dilutive securities:
Dilutive effect of share-based compensation (in shares)									102	75	85
Performance-Based Restricted Stock Units
Effect of dilutive securities:
Dilutive effect of share-based compensation (in shares)									124	143	146

Earnings Per Share (Details 1)

Earnings Per Share (Details 1) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock Appreciation Rights (SARs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Equity awards excluded from diluted EPS calculation	166,255	71,199	65,122

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 42,905	$ 35,612
Work in process	200,741	175,135
Finished goods	7,132	25,506
Inventories, net	$ 250,778	$ 236,253

Inventories (Details Textual)

Inventories (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Inventory [Line Items]
Notional Amount of Nonderivative Instruments	$ 400	$ 309.3

Property, Plant, and Equipmen_2

Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary of Property, plant and equipment
Property, plant, and equipment	$ 998,312	$ 916,965
Less allowances for depreciation, depletion, and amortization	(688,626)	(684,689)
Property, plant, and equipment — net	309,686	232,276	$ 251,018
Land
Summary of Property, plant and equipment
Property, plant, and equipment	5,686	4,874
Buildings
Summary of Property, plant and equipment
Property, plant, and equipment	165,144	150,323
Machinery and equipment
Summary of Property, plant and equipment
Property, plant, and equipment	645,195	639,310
Software
Summary of Property, plant and equipment
Property, plant, and equipment	43,652	44,652
Construction in progress
Summary of Property, plant and equipment
Property, plant, and equipment	69,297	16,699
Land Building Machinery and Equipment
Summary of Property, plant and equipment
Less allowances for depreciation, depletion, and amortization	(662,724)	(669,250)
Property, plant, and equipment — net	266,250	186,608
Capital leases
Summary of Property, plant and equipment
Property, plant, and equipment	34,301	26,069
Less allowances for depreciation, depletion, and amortization	(4,914)	(3,569)
Property, plant, and equipment — net	29,387	22,500
Mineral resources
Summary of Property, plant and equipment
Property, plant, and equipment	4,979	4,980
Mine development
Summary of Property, plant and equipment
Property, plant, and equipment	30,058	30,058
Productive land
Summary of Property, plant and equipment
Less allowances for depreciation, depletion, and amortization	(20,988)	(11,870)
Property, plant, and equipment — net	$ 14,049	$ 23,168

Property, Plant, and Equipmen_3

Property, Plant, and Equipment Textuals (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Reimbursement of costs	$ 63.5
Unearned Income	(4.3)	$ (4.4)	$ (4.3)
Depreciation and depletion expense	30.9	30.3	33.3
Net book value of capitalized software	5	7.9
Software amortization	$ 1.8	$ 2.4	$ 2.6

Customer Prepayments (Details)

Customer Prepayments (Details) $ in Millions	Dec. 31, 2020USD ($)
Revenue Recognition and Deferred Revenue [Abstract]
Future Customer Prepayments	$ 70
Deferred Income	$ 58.8

Leasing Arrangements Components

Leasing Arrangements Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Components of Lease Expense [Abstract]
Operating lease cost	$ 10,602	$ 9,835
Finance Leases
Amortization of right-of-use assets	1,324	1,414
Interest on lease liabilities	1,021	1,028
Total lease cost	$ 12,947	$ 12,277

Leasing Arrangements Supplement

Leasing Arrangements Supplemental Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Operating Leases
Operating lease, right-of-use assets	$ 62,089	$ 23,413
Operating lease liabilities	56,761	18,091
Finance Leases
Finance lease liabilities	20,539	17,424
Total principal payable on finance leases	23,464	18,689
Property, plant, and equipment	998,312	916,965
Allowances for depreciation, depletion, and amortization	(688,626)	$ (684,689)
Other liabilities and accrued items	$ 3,877
Weighted Average Remaining Lease Term Abstract [Abstract]
Operating leases	12 years 8 months 19 days	4 years 8 months 8 days
Finance leases	16 years 7 months 2 days	19 years 5 months 19 days
Weighted Average Discount Rate Abstract [Abstract]
Operating leases	6.46%	5.91%
Finance leases	4.88%	5.31%
Property, Plant and Equipment
Property, plant, and equipment	$ 34,301	$ 26,069
Allowances for depreciation, depletion, and amortization	(4,914)	(3,570)
Finance lease assets, net	29,387	22,499
Accrued Liabilities
Other liabilities and accrued items	2,925	1,265
Other liabilities and accrued items	$ 6,908	$ 6,542

Future Estimated Minimum Paymen

Future Estimated Minimum Payments Under Finance Leases and Non-Cancelable Operating Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finance Leases
2021	$ 3,877
2022	3,827
2023	2,536
2024	1,595
2025	1,432
2026 and thereafter	21,906
Total minimum lease payments	35,173
Amounts representing interest	11,709
Present value of lease payments	23,464	$ 18,689
Operating Leases
2021	10,707
2022	9,415
2023	8,750
2024	6,608
2025	6,278
2026 and thereafter	53,041
Total minimum lease payments	94,799
Amounts representing interest	31,130
Present value of lease payments	$ 63,669

Leasing Arrangements Suppleme_2

Leasing Arrangements Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Supplemental Cash Flow Information Related to Leases [Abstract]
Right-of-use asset obtained in exchange for operating lease liability	$ 43,037	$ 32,534
Right-of-use asset obtained in exchange for finance lease liability	6,736	3,919
Cash Paid For Amounts Included In Measurement Of Lease Liabilities
Operating cash flows from operating leases	16,216	15,841
Operating cash flows from finance leases	1,021	1,028
Financing cash flows from finance leases	$ 2,213	$ 1,200

Leasing Arrangements (Details T

Leasing Arrangements (Details Text) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2018
Leases [Abstract]
Operating lease expense		$ 11.6
Operating lease term maximum	25 years

Intangible Assets and Goodwil_2

Intangible Assets and Goodwill (Details 1) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Summary of cost, accumulated amortization and net book value of intangible assets
Cost	$ 109,603	$ 57,235
Accumulated amortization	(56,903)	(53,554)
Finite-lived intangible assets, net	54,672	6,380
Customer Relationships
Summary of cost, accumulated amortization and net book value of intangible assets
Cost	81,231	39,601
Accumulated amortization	(38,773)	(37,692)
Finite-lived intangible assets, net	42,458	1,909
Technology
Summary of cost, accumulated amortization and net book value of intangible assets
Cost	16,915	13,377
Accumulated amortization	(13,290)	(12,816)
Finite-lived intangible assets, net	3,625	561
Licenses and other
Summary of cost, accumulated amortization and net book value of intangible assets
Cost	11,457	4,257
Accumulated amortization	(4,840)	(3,046)
Finite-lived intangible assets, net	6,617	1,211
Finite-Lived Intangible Assets
Summary of cost, accumulated amortization and net book value of intangible assets
Finite-lived intangible assets, net	$ 52,700	$ 3,681

Intangible Assets and Goodwil_3

Intangible Assets and Goodwill (Details 2) $ in Thousands	Dec. 31, 2020USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2021	$ 4,596
2022	4,585
2023	4,565
2024	4,563
2025	$ 4,084

Intangible Assets and Goodwil_4

Intangible Assets and Goodwill Goodwill Table (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill	$ 144,916,000	$ 79,011,000	$ 90,657,000
Goodwill, acquired during period	70,577,000
Goodwill impairment charges	(9,053,000)	(11,560,000)	0
Goodwill, other increase (decrease)	4,381,000	(86,000)
Performance Alloys and Composites
Goodwill [Line Items]
Goodwill	1,899,000	1,899,000	1,899,000
Goodwill, acquired during period	0
Goodwill impairment charges	0	0	0
Goodwill, other increase (decrease)	0	0
Advanced Materials
Goodwill [Line Items]
Goodwill	50,527,000	50,190,000	50,276,000
Goodwill, acquired during period	0
Goodwill impairment charges	0	0	0
Goodwill, other increase (decrease)	337,000	(86,000)
Precision Optics
Goodwill [Line Items]
Goodwill	92,490,000	26,922,000	38,482,000
Goodwill, acquired during period	70,577,000
Goodwill impairment charges	(9,053,000)	(11,560,000)	$ 0
Goodwill, other increase (decrease)	$ 4,044,000	$ 0

Intangible Assets and Goodwil_5

Intangible Assets and Goodwill (Details Textual) - USD ($)	Jul. 17, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Line Items]
Business combination, consideration transferred	$ 136,100,000
Goodwill		$ 144,916,000	$ 79,011,000	$ 90,657,000
Asset impairment charges		1,419,000	2,581,000	0
Goodwill impairment charges		9,053,000	11,560,000	0
Deferred finance cost		0	90,000
Amortization of intangible assets		2,377,000	1,400,000	2,265,000
Optics Balzers [Member]
Goodwill [Line Items]
Intangible assets	49,300,000
Goodwill	$ 70,639,000
Performance Alloys and Composites
Goodwill [Line Items]
Goodwill		1,899,000	1,899,000	1,899,000
Goodwill impairment charges		0	0	0
Precision Optics
Goodwill [Line Items]
Goodwill		92,490,000	26,922,000	38,482,000
Goodwill impairment charges		9,053,000	11,560,000	0
Accumulated impairment loss		20,600,000	11,600,000
Advanced Materials
Goodwill [Line Items]
Goodwill		50,527,000	50,190,000	50,276,000
Goodwill impairment charges		0	0	$ 0
Deferred Financing Costs
Goodwill [Line Items]
Deferred finance cost		$ 2,000,000	$ 2,700,000
Technology | Optics Balzers [Member]
Goodwill [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	5 years
Intangible assets	$ 4,059,000
License | Optics Balzers [Member]
Goodwill [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	5 years
Intangible assets	$ 5,100,000
Customer Relationships | Optics Balzers [Member]
Goodwill [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	18 years
Intangible assets	$ 40,141,000

Debt (Details)

Debt (Details) - USD ($)	Dec. 31, 2020	Jun. 26, 2020	Dec. 31, 2019
Summary of long-term debt
Line of Credit Facility, Interest Rate at Period End	1.65%
Borrowings under Credit Agreement with average interest rate of 1.65% at December 31, 2020	$ 34,000,000	$ 150,000,000	$ 0
Foreign debt	3,157,000		0
Fixed rate industrial development revenue bonds payable in annual installments through 2021	1,322,000		2,218,000
Total long-term debt outstanding	38,479,000		2,218,000
Current portion of long-term debt	(1,937,000)		(868,000)
Gross long-term debt	36,542,000		1,350,000
Unamortized deferred financing fees	0		(90,000)
Long-term debt	$ 36,542,000		$ 1,260,000

Debt (Details 1)

Debt (Details 1) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Maturities on long-term debt instruments
2021	$ 1,937
2022	500
2023	387
2024	34,387
2025	387
2026 and thereafter	881
Total long-term debt outstanding	$ 38,479	$ 2,218

Debt (Details Textual)

Debt (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2020	Jun. 26, 2020	Dec. 31, 2019
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 375,000,000
Borrowings under Credit Agreement with average interest rate of 1.65% at December 31, 2020	34,000,000	$ 150,000,000	$ 0
Additional term loan
Line of Credit Facility [Line Items]
Maximum borrowing capacity	200,000,000
Letter of Credit
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	$ 48,100,000		$ 41,800,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Variable commitment fee	0.20%
Short-term Debt [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	$ 245,800,000

Debt (Details Textual 2)

Debt (Details Textual 2) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Line of Credit Facility [Line Items]
Debt Instrument, Face Amount	$ 8,000
Interest rate on bonds	4.90%
Unamortized balance of bonds	$ 1,322	$ 2,218

Reconciliation of the Benefit O

Reconciliation of the Benefit Obligations and Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan Assets Beginning of the Year	$ 174,046
Plan Assets End of the Year	226,176	$ 174,046
Pension Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation Beginning of the Year	186,760	170,136
Service cost	1,403	5,918	$ 6,953
Interest cost	5,234	6,292	9,554
Net pension curtailment and settlements	(609)	(12,212)
Acquisition	30,360	0
Plan amendments	(799)	0
Actuarial loss (gain)	24,259	20,409
Benefit payments	(4,612)	(3,170)
Foreign currency exchange rate changes and other	4,111	(613)
Benefit Obligation End of the Year	246,107	186,760	170,136
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan Assets Beginning of the Year	174,046	145,046
Plan settlements	0	0
Acquisition	23,774	0
Actual return on plan assets	30,330	27,264
Employer contributions	614	4,702
Employee contributions	498	124
Benefit payments from fund	(4,720)	(2,933)
Expenses paid from assets	(234)	(391)
Foreign currency exchange rate changes and other	1,868	234
Plan Assets End of the Year	226,176	174,046	145,046
Funded status at end of year	(19,931)	(12,714)
Other assets	13,074	11,298
Other liabilities and accrued items	470	997
Retirement and post-employment benefits	32,535	23,015
Other Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation Beginning of the Year	8,681	11,375
Service cost	59	67	111
Interest cost	213	399	396
Net pension curtailment and settlements	0	0
Acquisition	0	0
Plan amendments	0	0
Actuarial loss (gain)	224	(2,192)
Benefit payments	(989)	(981)
Foreign currency exchange rate changes and other	2	13
Benefit Obligation End of the Year	8,190	8,681	11,375
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan Assets Beginning of the Year	0	0
Plan settlements	0	0
Acquisition	0	0
Actual return on plan assets	0	0
Employer contributions	0	0
Employee contributions	0	0
Benefit payments from fund	0	0
Expenses paid from assets	0	0
Foreign currency exchange rate changes and other	0	0
Plan Assets End of the Year	0	0	$ 0
Funded status at end of year	(8,190)	(8,681)
Other assets	0	0
Other liabilities and accrued items	866	1,012
Retirement and post-employment benefits	$ 7,324	$ 7,669

Amounts Recognized in Other Com

Amounts Recognized in Other Comprehensive Income (Before Tax) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits
Defined Benefit Plan Disclosure
Net actuarial loss (gain)	$ 49,472	$ 48,073
Net prior service cost (credit)	(799)	0
Net amount recognized	48,673	48,073
Other Benefits
Defined Benefit Plan Disclosure
Net actuarial loss (gain)	(3,973)	(4,529)
Net prior service cost (credit)	(3,552)	(5,049)
Net amount recognized	$ (7,525)	$ (9,578)

Accumulated Benefit Obligation

Accumulated Benefit Obligation (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Other Pension Plan
Defined Benefit Plan Disclosure
Accumulated benefit obligation for all defined benefit pension plans	$ 243,953	$ 185,402
Defined Benefit Plan, Pension Plan with Project Benefit Obligation in Excess of Plan Assets [Abstract]
Aggregate benefit obligation	62,012	25,640
Aggregate fair value of plan assets	29,938	3,045
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Aggregate accumulated benefit obligation	59,858	24,482
Aggregate fair value of plan assets	29,938	3,045
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure
Accumulated benefit obligation for all defined benefit pension plans	0	0
Defined Benefit Plan, Pension Plan with Project Benefit Obligation in Excess of Plan Assets [Abstract]
Aggregate benefit obligation	0	0
Aggregate fair value of plan assets	0	0
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Aggregate accumulated benefit obligation	0	0
Aggregate fair value of plan assets	$ 0	$ 0

Components of Net Benefit Costs

Components of Net Benefit Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure
Net pension curtailments and settlements			$ 41,400
Other Pension Plan
Defined Benefit Plan Disclosure
Service cost	$ 1,403	$ 5,918	6,953
Interest cost	5,234	6,292	9,554
Expected return on plan assets	(9,333)	(8,777)	(14,231)
Amortization of prior service credit	0	483	(123)
Recognized net actuarial loss (gain)	1,678	3,304	7,171
Net periodic benefit (credit) cost	(1,018)	7,220	9,324
Net pension curtailments and settlements	94	3,328	41,406
Total net benefit (credit) cost	(924)	10,548	50,730
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure
Service cost	59	67	111
Interest cost	213	399	396
Expected return on plan assets	0	0	0
Amortization of prior service credit	(1,497)	(1,497)	(1,497)
Recognized net actuarial loss (gain)	(332)	(93)	0
Net periodic benefit (credit) cost	(1,557)	(1,124)	(990)
Net pension curtailments and settlements	0	0	0
Total net benefit (credit) cost	$ (1,557)	$ (1,124)	$ (990)

Pensions and Other Post-Emplo_3

Pensions and Other Post-Employment Benefits Amounts Recognized in AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Pension Plan
Defined Benefit Plan Disclosure
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	$ 48,673	$ 48,073	$ 65,409	$ 122,802
Recognized during year — prior service cost (credit)	0	(3,811)	123
Recognized during year — net actuarial (losses) gains	(1,678)	(3,304)	(7,171)
Occurring during year — prior service cost	(799)	0	0
Occurring during year — net actuarial losses (gains)	3,146	2,062	(8,997)
Other adjustments	(94)	(12,212)	(41,406)
Foreign currency exchange rate changes	25	(71)	58
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	(7,525)	(9,578)	(8,976)	$ (8,020)
Recognized during year — prior service cost (credit)	1,497	1,497	1,497
Recognized during year — net actuarial (losses) gains	332	93	0
Occurring during year — prior service cost	0	0	0
Occurring during year — net actuarial losses (gains)	224	(2,192)	(2,453)
Other adjustments	0	0	0
Foreign currency exchange rate changes	$ 0	$ 0	$ 0

Pensions and Other Post-Emplo_4

Pensions and Other Post-Employment Benefits Weighted Average Assumptions (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	3.00%	4.00%
Other Pension Plan
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	2.14%	3.12%	4.07%
Rate of compensation increase	2.22%	3.00%	3.87%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	8.37%	4.16%	3.63%
Expected long-term rate of return on plan assets	5.70%	6.06%	6.63%
Rate of compensation increase	2.87%	2.99%	3.98%
Other Postretirement Benefits Plan
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	2.45%	3.20%	4.11%
Rate of compensation increase	3.00%	3.00%	4.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.20%	4.11%	3.43%
Rate of compensation increase	3.00%	4.00%	4.00%

Pensions and Other Post-Emplo_5

Pensions and Other Post-Employment Benefits (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Retirement Benefits [Abstract]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	6.00%	6.25%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	5.00%	5.00%
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate	2025	2025

Pensions and Other Post-Emplo_6

Pensions and Other Post-Employment Benefits Plan Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	$ 226,176	$ 174,046
Fair Value of Plan Assets Excluding Net Asset Value Investments	77,977	56,484
Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets Excluding Net Asset Value Investments	77,977	56,484
Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets Excluding Net Asset Value Investments	0	0
Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets Excluding Net Asset Value Investments	0	0
Cash and Cash Equivalents
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	2,204	1,718
Cash and Cash Equivalents | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	2,204	1,718
Cash and Cash Equivalents | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	0	0
Cash and Cash Equivalents | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	0	0
Equity securities
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	49,293	47,722
Equity securities | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	49,293	47,722
Equity securities | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	0	0
Equity securities | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	0	0
Fixed Income Securities
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	20,375	3,923
Fixed Income Securities | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	20,375	3,923
Fixed Income Securities | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	0	0
Fixed Income Securities | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	0	0
Real Estate
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	6,105	3,121
Real Estate | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	6,105	3,121
Real Estate | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	0	0
Real Estate | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	0	0
Pooled Investment Fund
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	143,503	113,187
Hedge Funds, Multi-strategy
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	4,624	4,277
Private Equity Funds
Defined Benefit Plan Disclosure
Plan Assets, Fair Value	$ 72	$ 98

Pensions and Other Post-Emplo_7

Pensions and Other Post-Employment Benefits Cash Flow (Details) $ in Thousands	Dec. 31, 2020USD ($)
Pension Plan
Defined Benefit Plan Disclosure
2021	$ 4,987
2022	5,854
2023	7,401
2024	8,689
2025	8,924
2026 through 2030	54,116
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure
2021	867
2022	812
2023	746
2024	667
2025	603
2026 through 2030	2,140
Net of Medicare Part D Subsidy
Defined Benefit Plan Disclosure
2021	853
2022	800
2023	736
2024	659
2025	596
2026 through 2030	$ 2,120

Pensions and Other Post-Emplo_8

Pensions and Other Post-Employment Benefits (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension and other post-retirement benefits (Textual) [Abstract]
Non-cash pretax pension curtailment charge	$ (94,000)	$ (3,328,000)	$ (41,406,000)
Pension settlement charges			41,400,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	3.00%	4.00%
Mutual fund that typically invests at least 80% of its assets in equity and debt securities	80.00%
Target funded status percentage	100.00%
Current asset allocation to invest in alternative securities, maximum	20.00%
Liability for other post-employment arrangements	$ 41,877,000	$ 32,466,000
Company's annual contributions	9,800,000	7,000,000	5,200,000
Other Pension Plan
Pension and other post-retirement benefits (Textual) [Abstract]
Pension settlement charges	$ 94,000	$ 3,328,000	$ 41,406,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	2.22%	3.00%	3.87%
Other Postretirement Benefits Plan
Pension and other post-retirement benefits (Textual) [Abstract]
Pension settlement charges	$ 0	$ 0	$ 0
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	3.00%	3.00%	4.00%
Foreign Plan
Pension and other post-retirement benefits (Textual) [Abstract]
Liability for other post-employment arrangements	$ 1,700,000	$ 1,400,000
Maximum
Pension and other post-retirement benefits (Textual) [Abstract]
Lump sum program payments	$ 100,000
Equity securities | Minimum
Pension and other post-retirement benefits (Textual) [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	10.00%
Equity securities | Maximum
Pension and other post-retirement benefits (Textual) [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	40.00%
Fixed Income Funds | Minimum
Pension and other post-retirement benefits (Textual) [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	60.00%
Fixed Income Funds | Maximum
Pension and other post-retirement benefits (Textual) [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	90.00%

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current year activity:
Accumulated other comprehensive loss	$ (38,639)	$ (45,462)	$ (58,234)	$ (102,937)
Other comprehensive income (loss) before reclassifications	3,584	7,696	10,477
Amounts reclassified from accumulated other comprehensive income	2,560	9,812	46,854
Other comprehensive income (loss) before tax	6,144	17,508	57,331
Deferred taxes on current period activity	(679)	4,736	12,628
Other comprehensive income (loss) after tax	6,823	12,772	44,703
Gains and Losses On Cash Flow Hedges
Current year activity:
Accumulated other comprehensive loss	817	897	901	763
Other comprehensive income (loss) before reclassifications	(2,725)	(968)	(435)
Amounts reclassified from accumulated other comprehensive income	2,617	959	(99)
Other comprehensive income (loss) before tax	(108)	(9)	(534)
Deferred taxes on current period activity	(28)	(5)	(672)
Other comprehensive income (loss) after tax	(80)	(4)	138
Pension and Post- Employment Benefits
Current year activity:
Accumulated other comprehensive loss	(43,473)	(41,346)	(54,543)	(99,592)
Other comprehensive income (loss) before reclassifications	(2,721)	9,085	11,396
Amounts reclassified from accumulated other comprehensive income	(57)	8,853	46,953
Other comprehensive income (loss) before tax	(2,778)	17,938	58,349
Deferred taxes on current period activity	(651)	4,741	13,300
Other comprehensive income (loss) after tax	(2,127)	13,197	45,049
Foreign Currency Translation
Current year activity:
Accumulated other comprehensive loss	4,017	(5,013)	(4,592)	(4,108)
Other comprehensive income (loss) before reclassifications	9,030	(421)	(484)
Amounts reclassified from accumulated other comprehensive income	0	0	0
Other comprehensive income (loss) before tax	9,030	(421)	(484)
Deferred taxes on current period activity	0	0	0
Other comprehensive income (loss) after tax	9,030	(421)	(484)
Foreign Currency | Gains and Losses On Cash Flow Hedges
Current year activity:
Accumulated other comprehensive loss	519	1,324	1,263	959
Other comprehensive income (loss) before reclassifications	(1,268)	108	(333)
Amounts reclassified from accumulated other comprehensive income	222	(29)	10
Other comprehensive income (loss) before tax	(1,046)	79	(323)
Deferred taxes on current period activity	(241)	18	(627)
Other comprehensive income (loss) after tax	(805)	61	304
Precious Metals | Gains and Losses On Cash Flow Hedges
Current year activity:
Accumulated other comprehensive loss	(170)	(452)	79	(196)
Other comprehensive income (loss) before reclassifications	(1,675)	(1,285)	467
Amounts reclassified from accumulated other comprehensive income	2,041	595	(109)
Other comprehensive income (loss) before tax	366	(690)	358
Deferred taxes on current period activity	84	(159)	83
Other comprehensive income (loss) after tax	282	(531)	275
Copper Swap | Gains and Losses On Cash Flow Hedges
Current year activity:
Accumulated other comprehensive loss	468	25	(441)	$ 0
Other comprehensive income (loss) before reclassifications	218	209	(569)
Amounts reclassified from accumulated other comprehensive income	354	393	0
Other comprehensive income (loss) before tax	572	602	(569)
Deferred taxes on current period activity	129	136	(128)
Other comprehensive income (loss) after tax	$ 443	$ 466	$ (441)

Stock-Based Compensation Detail

Stock-Based Compensation Details Textual (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 25, 2020	Jun. 26, 2020	Mar. 27, 2020	Dec. 31, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based Compensation Expense									$ 5,700	$ 11,100	$ 11,400
Income Tax Expense (Benefit)	$ (1,210)	$ (6,345)	$ 1,360	$ (992)	$ 1,579	$ 2,578	$ 4,148	$ 3,837	(7,187)	12,142	(4,446)
Equity securities
Share-based Compensation Arrangement by Share-based Payment Award
Income Tax Expense (Benefit)									$ (500)	$ (2,100)	$ (1,200)

Stock-based Compensation Deta_2

Stock-based Compensation Details Textual SARs (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based Compensation Expense	$ 5.7	$ 11.1	$ 11.4
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award
Unearned Compensation	$ 0.9
Expected recognition period	20 months
Vested in period	$ 1.5	$ 1.9	$ 1.9
Granted (in dollars per share)	$ 13.67	$ 17.76	$ 15.73
Vesting period	3 years
Stock-based Compensation Expense	$ 0.9	$ 0.9	$ 0.7
Granted in 2011 and later | Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award
Expiration period	7 years

Stock-based Compensation Deta_3

Stock-based Compensation Details Table SARs Activity (Details) - Stock Appreciation Rights (SARs) $ / shares in Units, shares in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)$ / sharesshares
Number of SARs
Outstanding at December 31, 2019 | shares	250
Granted | shares	65
Exercised | shares	(29)
Forfeited | shares	(32)
Outstanding at December 31, 2020 | shares	254
Vested and expected to vest as of December 31, 2020 | shares	254
Exercisable at December 31, 2020 | shares	148
Weighted- Average Exercise Price Per Share
Outstanding at December 31, 2018 (in dollars per share) | $ / shares	$ 44.95
Granted (in dollars per share) | $ / shares	50.95
Exercised (in dollars per share) | $ / shares	40.70
Cancelled (in dollars per share) | $ / shares	51.43
Outstanding at December 31, 2019 (in dollars per share) | $ / shares	46.18
Vested and expected to vest as of December 31, 2020 (in dollars per share) | $ / shares	46.18
Exercisable at December 31, 2020 (in dollars per share) | $ / shares	$ 41
Aggregate Intrinsic Value
Outstanding at December 31, 2020 | $	$ 4,454
Vested and expected to vest as of December 31, 2020 | $	4,454
Exercisable at December 31, 2020 | $	$ 3,368
Weighted- Average Remaining Term (Years)
Outstanding at December 31, 2020	4 years 2 months 12 days
Vested and expected to vest as of December 31, 2020	4 years 2 months 12 days
Exercisable at December 31, 2020	3 years 4 months 24 days

Stock-based Compensation Deta_4

Stock-based Compensation Details Table SARs Status (Details) - Stock Appreciation Rights (SARs) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at December 31, 2019	178
Granted	65
Vested	(109)
Forfeited	(28)
Outstanding at December 31, 2020	106	178
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding at December 31, 2019 (in dollars per share)	$ 14.72
Granted (in dollars per share)	13.67	$ 17.76	$ 15.73
Vested (in dollars per share)	13.21
Forfeited (in dollars per share)	15.50
Outstanding at December 31, 2020 (in dollars per share)	$ 15.46	$ 14.72

Stock-based Compensation Deta_5

Stock-based Compensation Details Table SARs Fair Value (Details) - Stock Appreciation Rights (SARs)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Risk-free interest rate	1.41%	2.47%	2.58%
Dividend yield	0.90%	0.70%	0.80%
Volatility	31.80%	31.70%	31.90%
Expected lives (in years)	4 years 9 months 18 days	5 years 2 months 12 days	5 years 6 months

Stock-based Compensation Deta_6

Stock-based Compensation Details Textual RSUs (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based Compensation Expense	$ 5.7	$ 11.1	$ 11.4
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period	3 years
Granted (in dollars per share)	$ 13.67	$ 17.76	$ 15.73
Stock-based Compensation Expense	$ 0.9	$ 0.9	$ 0.7
Unearned Compensation	$ 0.9
Expected amortization weighted average period	20 months
Vested in period	$ 1.5	$ 1.9	$ 1.9
Stock Incentive Plan | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period	3 years
Granted (in dollars per share)	$ 51.55	$ 58.33	$ 50.35
Stock-based Compensation Expense	$ 2.7	$ 2.2	$ 1.2
Unearned Compensation	$ 4.3
Expected amortization weighted average period	28 months
Vested in period	$ 1.2	$ 1.2	$ 1.4

Stock-based Compensation Deta_7

Stock-based Compensation Details Table RSUs Activity (Details) - Stock Incentive Plan - Restricted Stock Units (RSUs) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of Shares
Outstanding at December 31, 2019	145
Granted	84
Vested	(33)
Forfeited	(35)
Outstanding at December 31, 2020	161	145
Weighted- average Grant Date Fair Value
Outstanding at December 31, 2019 (in dollars per share)	$ 50.79
Granted (in dollars per share)	51.55	$ 58.33	$ 50.35
Vested (in dollars per share)	36.39
Forfeited (in dollars per share)	53.52
Outstanding at December 31, 2020 (in dollars per share)	$ 53.50	$ 50.79

Stock-based compensation Deta_8

Stock-based compensation Details Textual RSUs Non-Employee Directors (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based Compensation Expense	$ 5.7	$ 11.1	$ 11.4
Restricted Stock Units (RSUs) | Director Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award
Granted	15,976	11,048	14,728
Vesting period	1 year
Granted (in dollars per share)	$ 48.42	$ 68.79	$ 51.60
Stock-based Compensation Expense	$ 0.7	$ 0.7	$ 0.7
Unearned Compensation	$ 0.3
Expected amortization weighted average period	4 months

Stock-based Compensation Deta_9

Stock-based Compensation Details Textual LTIP (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based Compensation Expense	$ 5.7	$ 11.1	$ 11.4
Performance-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period	3 years
Stock-based Compensation Expense	$ 2	$ 3.3	$ 2.7
Performance-Based Restricted Stock Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of Units Earned of Units Granted	0.00%
Performance-Based Restricted Stock Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of Units Earned of Units Granted	200.00%

Stock-based Compensation Det_10

Stock-based Compensation Details Table PRSUs Activity (Details) - Performance-Based Restricted Stock Units shares in Thousands	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Number of Shares
Outstanding at December 31, 2019 | shares	169
Granted | shares	46
Vested | shares	(63)
Forfeited | shares	(26)
Outstanding at December 31, 2020 | shares	126
Weighted- Average Grant Date Fair Value
Outstanding at December 31, 2019 (in dollars per share) | $ / shares	$ 52.74
Granted (in dollars per share) | $ / shares	57.65
Vested (in dollars per share) | $ / shares	30.28
Forfeited (in dollars per share) | $ / shares	63.59
Outstanding at December 31, 2020 (in dollars per share) | $ / shares	$ 63.61

Stock-based Compensation Det_11

Stock-based Compensation Details Textual DDP (Details) shares in Millions	12 Months Ended
	Dec. 31, 2020shares
Share-based Payment Arrangement [Abstract]
Shares Deferred	0.1

Fair Value Information and De_3

Fair Value Information and Derivative Financial Instruments (Details 1) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Measurements, Recurring
Financial Assets
Assets Fair Value Disclosure	$ 4,668	$ 3,675
Financial Liabilities
Liabilities Fair Value Disclosure	5,381	4,253
Fair Value, Measurements, Recurring | Copper Swap
Financial Assets
Assets Fair Value Disclosure	632	61
Financial Liabilities
Liabilities Fair Value Disclosure	27	28
Fair Value, Measurements, Recurring | Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member]
Financial Assets
Assets Fair Value Disclosure	3,802	3,391
Financial Liabilities
Liabilities Fair Value Disclosure	3,802	3,391
Fair Value, Measurements, Recurring | Forward Contracts [Member]
Financial Assets
Assets Fair Value Disclosure	107	188
Financial Liabilities
Liabilities Fair Value Disclosure	1,203	211
Fair Value, Measurements, Recurring | Swap [Member]
Financial Assets
Assets Fair Value Disclosure	127	35
Financial Liabilities
Liabilities Fair Value Disclosure	349	623
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Financial Assets
Assets Fair Value Disclosure	0	0
Financial Liabilities
Liabilities Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member]
Financial Assets
Assets Fair Value Disclosure	0	0
Financial Liabilities
Liabilities Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Forward Contracts [Member]
Financial Assets
Assets Fair Value Disclosure	0	0
Financial Liabilities
Liabilities Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Swap [Member]
Financial Assets
Assets Fair Value Disclosure	0	0
Financial Liabilities
Liabilities Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Copper Swap
Financial Assets
Assets Fair Value Disclosure	0	0
Financial Liabilities
Liabilities Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Financial Assets
Assets Fair Value Disclosure	866	284
Financial Liabilities
Liabilities Fair Value Disclosure	1,579	862
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member]
Financial Assets
Assets Fair Value Disclosure	0	0
Financial Liabilities
Liabilities Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Forward Contracts [Member]
Financial Assets
Assets Fair Value Disclosure	107	188
Financial Liabilities
Liabilities Fair Value Disclosure	1,203	211
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Swap [Member]
Financial Assets
Assets Fair Value Disclosure	127	35
Financial Liabilities
Liabilities Fair Value Disclosure	349	623
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Copper Swap
Financial Assets
Assets Fair Value Disclosure	632	61
Financial Liabilities
Liabilities Fair Value Disclosure	27	28
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Financial Assets
Assets Fair Value Disclosure	3,802	3,391
Financial Liabilities
Liabilities Fair Value Disclosure	3,802	3,391
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member]
Financial Assets
Assets Fair Value Disclosure	3,802	3,391
Financial Liabilities
Liabilities Fair Value Disclosure	3,802	3,391
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Forward Contracts [Member]
Financial Assets
Assets Fair Value Disclosure	0	0
Financial Liabilities
Liabilities Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Swap [Member]
Financial Assets
Assets Fair Value Disclosure	0	0
Financial Liabilities
Liabilities Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Copper Swap
Financial Assets
Assets Fair Value Disclosure	0	0
Financial Liabilities
Liabilities Fair Value Disclosure	0	0
Not Designated as Hedging Instrument [Member] | Foreign currency forward contracts - euro | Prepaid Expenses and Other Current Assets | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Notional Amount	62,012	13,734
Derivative Asset, Fair Value, Gross Asset	107	95
Not Designated as Hedging Instrument [Member] | Foreign currency forward contracts - euro | Accrued Liabilities | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Notional Amount	7,695	5,757
Derivative Liability, Fair Value, Gross Liability	$ 55	$ 16

Fair Value Information and De_4

Fair Value Information and Derivative Financial Instruments (Details 2) - Foreign currency forward contracts - euro - Foreign Exchange Forward - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Prepaid Expenses and Other Current Assets
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Asset, Notional Amount	$ 62,012	$ 13,734
Derivative Asset, Fair Value, Gross Asset	107	95
Accrued Liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Liability, Notional Amount	7,695	5,757
Derivative Liability, Fair Value, Gross Liability	$ 55	$ 16

Fair Value Information and De_5

Fair Value Information and Derivative Financial Instruments (Details 3) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	$ 36,068	$ 34,205
Derivative, Fair Value, Net	765	657
Designated as Hedging Instrument | Other liabilities and accrued items
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Liability, Notional Amount	27,688	26,341
Derivative Liability, Fair Value, Gross Liability	1,524	841
Foreign Exchange Forward | Designated as Hedging Instrument | Prepaid Expenses and Other Current Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Asset, Notional Amount	8,380	7,558
Derivative Asset, Fair Value, Gross Asset	759	188
Foreign Exchange Forward | Foreign currency forward contracts - yen | Other liabilities and accrued items
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Liability, Notional Amount	2,668	2,355
Derivative Liability, Fair Value, Gross Liability	59	12
Foreign Exchange Forward | Foreign currency forward contracts - yen | Designated as Hedging Instrument | Prepaid Expenses and Other Current Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Asset, Notional Amount	0	1,025
Derivative Asset, Fair Value, Gross Asset	0	10
Foreign Exchange Forward | Foreign currency forward contracts - euro | Designated as Hedging Instrument | Prepaid Expenses and Other Current Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Asset, Notional Amount	0	3,466
Derivative Asset, Fair Value, Gross Asset	0	83
Foreign Exchange Forward | Foreign currency forward contracts - euro | Designated as Hedging Instrument | Other liabilities and accrued items
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Liability, Notional Amount	17,611	15,686
Derivative Liability, Fair Value, Gross Liability	1,089	183
Copper Swap | Designated as Hedging Instrument | Prepaid Expenses and Other Current Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Asset, Notional Amount	6,225	1,951
Derivative Asset, Fair Value, Gross Asset	632	61
Copper Swap | Designated as Hedging Instrument | Other liabilities and accrued items
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Liability, Notional Amount	2,445	1,266
Derivative Liability, Fair Value, Gross Liability	27	28
Precious Metal Swaps | Designated as Hedging Instrument | Prepaid Expenses and Other Current Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Asset, Notional Amount	2,155	1,116
Derivative Asset, Fair Value, Gross Asset	127	34
Precious Metal Swaps | Designated as Hedging Instrument | Other Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Asset, Notional Amount	0	157
Derivative Asset, Fair Value, Gross Asset	0	1
Precious Metal Swaps | Designated as Hedging Instrument | Other liabilities and accrued items
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Liability, Notional Amount	4,964	7,034
Derivative Liability, Fair Value, Gross Liability	349	618
Precious Metal Swaps | Designated as Hedging Instrument | Other Noncurrent Liabilities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Liability, Notional Amount	0	149
Derivative Liability, Fair Value, Gross Liability	$ 0	$ 5

Fair Value Information and De_6

Fair Value Information and Derivative Financial Instruments Fair Value Information and Derivative Financial Instruments (Details 4) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 2,617	$ 959
Foreign Exchange Forward | Sales [Member] | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	222	(29)
Precious Metal Swaps | Cost of Sales [Member] | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	2,041	595
Copper Swap | Cost of Sales [Member] | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 354	$ 393

Fair Value Information and De_7

Fair Value Information and Derivative Financial Instruments (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gain (Loss) on Foreign Currency Derivatives Recorded in Earnings, Net	$ 2.7	$ (0.1)
Total derivative ineffectiveness expense	0	0	$ 0
Total fair value of derivative contracts in AOCI	(0.8)	$ (0.7)
Derivative, Gain (Loss) on Derivative, Net	$ (0.8)

Contingencies and Commitments_2

Contingencies and Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Undiscounted reserve
Reserve balance at beginning of year	$ 5,937	$ 6,521
Expensed	288	482
Paid	(749)	(1,066)
Reserve balance at end of year	5,476	5,937
Ending balance recorded in:
Other liabilities and accrued items	845	982
Other long-term liabilities	$ 4,631	$ 4,955

Contingencies and Commitments_3

Contingencies and Commitments (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Asset retirement obligation at beginning of period	$ 1,421	$ 1,257
Accretion expense	137	164
Change in liability	207	0
Asset retirement obligation at end of period	$ 1,765	$ 1,421

Contingencies and Commitments_4

Contingencies and Commitments (Details Textual) $ in Millions	Dec. 31, 2020USD ($)claim	Dec. 31, 2019USD ($)claim
Contingencies And Commitments (Textual) [Abstract]
Number of CBD cases pending | claim	2	1
Letter of Credit
Contingencies And Commitments (Textual) [Abstract]
Outstanding letters of credit | $	$ 48.1	$ 41.8

Quarterly Data (Unaudited) (Det

Quarterly Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 25, 2020	Jun. 26, 2020	Mar. 27, 2020	Dec. 31, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 339,689	$ 287,171	$ 271,468	$ 277,946	$ 280,161	$ 305,979	$ 297,843	$ 301,441	$ 1,176,274	$ 1,185,424	$ 1,207,815
Summary of selected quarterly financial data
Gross margin	$ 55,797	$ 45,311	$ 46,955	$ 44,570	$ 54,482	$ 66,605	$ 71,997	$ 69,606	$ 192,633	$ 262,690	251,361
Percent of net sales	16.40%	15.80%	17.30%	16.00%	19.40%	21.80%	24.20%	23.10%	16.40%	22.20%
Net income	$ 8,066	$ 5,471	$ 5,803	$ (3,878)	$ 14,346	$ 4,522	$ 17,393	$ 17,133	$ 15,462	$ 53,394	$ 21,044
Net income per share of common stock:
Basic EPS (in usd per share)	$ 0.40	$ 0.27	$ 0.29	$ (0.19)	$ 0.70	$ 0.22	$ 0.85	$ 0.85	$ 0.76	$ 2.62	$ 1.04
Diluted EPS (in usd per share)	$ 0.39	$ 0.27	$ 0.28	$ (0.19)	$ 0.69	$ 0.22	$ 0.84	$ 0.83	$ 0.75	$ 2.59	$ 1.02

Quarterly Data (Unaudited) (D_2

Quarterly Data (Unaudited) (Details Textual) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 27, 2020	Sep. 27, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Impairment charges	$ 10,800	$ 14,100	$ 10,472	$ 14,141	$ 0

Valuation and Qualifying Acco_2

Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts receivable
Deducted from asset accounts:
Balance at Beginning of Period	$ 392	$ 616	$ 640
Charged to Costs and Expenses	224	(39)	271
Deductions	(80)	(185)	(295)
Balance at End of Period	536	392	616
Inventory reserves and obsolescence
Deducted from asset accounts:
Balance at Beginning of Period	14,697	13,065	14,381
Charged to Costs and Expenses	9,282	2,367	3,175
Deductions	(1,830)	(735)	(4,491)
Balance at End of Period	22,149	14,697	13,065
Valuation allowance on deferred tax assets
Deducted from asset accounts:
Balance at Beginning of Period	17,676	15,917	16,246
Charged to Costs and Expenses	884	2,475	9,700
Deductions	(4,426)	(716)	(10,029)
Balance at End of Period	$ 14,134	$ 17,676	$ 15,917