Belden (BDC) 10-K 16 Feb 21 2020 FY Annual report Financial data

Cover

Cover - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 10, 2021	Jun. 28, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-12561
Entity Registrant Name	BELDEN INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	36-3601505
Entity Address, Address Line One	1 North Brentwood Boulevard
Entity Address, Address Line Two	15th Floor
Entity Address, City or Town	St. Louis
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63105
City Area Code	314
Local Phone Number	854-8000
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	BDC
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity File Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging growth company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,314,089,562
Entity Common Stock, Shares Outstanding		44,657,019
Documents Incorporated by Reference	The registrant intends to file a definitive proxy statement for its annual meeting of stockholders within 120 days of the end of the fiscal year ended December 31, 2020 (the “Proxy Statement”). Portions of such proxy statement are incorporated by reference into Part III.
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0000913142

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 501,994	$ 407,480
Receivables, net	296,817	334,634
Inventories, net	247,298	231,333
Other current assets	52,289	29,172
Current assets of discontinued operations	0	375,135
Total current assets	1,098,398	1,377,754
Property, plant and equipment, less accumulated depreciation	368,620	345,918
Operating lease right-of-use assets	54,787	62,251
Goodwill	1,251,938	1,243,669
Intangible assets, less accumulated amortization	287,071	339,505
Deferred income taxes	29,536	25,216
Other long-lived assets	49,384	12,446
Total assets	3,139,734	3,406,759
Current liabilities:
Accounts payable	244,120	268,466
Accrued liabilities	276,641	283,799
Current liabilities of discontinued operations	0	170,279
Total current liabilities	520,761	722,544
Long-term debt	1,573,726	1,439,484
Postretirement benefits	160,400	136,227
Deferred income taxes	38,400	48,725
Long-term operating lease liabilities	46,398	55,652
Other long-term liabilities	42,998	38,308
Stockholders’ equity:
Common stock, par value $0.01 per share— 200,000 shares authorized; 50,335 shares issued; 44,643 and 45,458 shares outstanding at 2020 and 2019, respectively	503	503
Additional paid-in capital	823,605	811,955
Retained earnings	450,876	518,004
Accumulated other comprehensive loss	(191,851)	(63,418)
Treasury stock, at cost— 5,692 and 4,877 shares at 2020 and 2019, respectively	(332,552)	(307,197)
Total Belden stockholders’ equity	750,581	959,847
Noncontrolling interest	6,470	5,972
Total stockholders’ equity	757,051	965,819
Total liabilities and stockholders' equity	$ 3,139,734	$ 3,406,759

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	50,335,000	50,335,000
Common stock, shares outstanding (in shares)	44,643,000	45,458,000
Treasury stock, shares (in shares)	5,692,000	4,877,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenues	$ 1,862,716	$ 2,131,278	$ 2,165,702
Cost of sales	(1,199,427)	(1,337,773)	(1,335,791)
Gross profit	663,289	793,505	829,911
Selling, general and administrative expenses	(366,188)	(417,329)	(411,352)
Research and development expenses	(107,296)	(94,360)	(91,552)
Amortization of intangibles	(64,395)	(74,609)	(75,140)
Gain from patent litigation	0	0	62,141
Operating income	125,410	207,207	314,008
Interest expense, net	(58,888)	(55,814)	(60,839)
Non-operating pension benefit (cost)	(395)	1,017	(99)
Loss on debt extinguishment	0	0	(22,990)
Income from continuing operations before taxes	66,127	152,410	230,080
Income tax expense	(11,724)	(42,519)	(62,936)
Income from continuing operations	54,403	109,891	167,144
Loss from discontinued operations, net of tax	(99,513)	(486,667)	(6,433)
Gain on disposal	(9,948)	0	0
Net income (loss)	(55,058)	(376,776)	160,711
Less: Net income (loss) attributable to noncontrolling interest	104	239	(183)
Net income (loss) attributable to Belden	(55,162)	(377,015)	160,894
Less: Preferred stock dividends	0	18,437	34,931
Net income (loss) attributable to Belden common stockholders	$ (55,162)	$ (395,452)	$ 125,963
Weighted average number of common shares and equivalents:
Basic (in shares)	44,778	42,203	40,675
Diluted (in shares)	44,937	42,416	40,956
Basic income (loss) per share attributable to Belden common stockholders:
Continuing operations attributable to Belden common stockholders (in dollars per share)	$ 1.21	$ 2.16	$ 3.25
Discontinued operations attributable to Belden common stockholders (in dollars per share)	(2.22)	(11.53)	(0.16)
Disposal of discontinued operations attributable to Belden common stockholders (in dollars per share)	(0.22)	0	0
Net income (loss) attributable to Belden common stockholders (in dollars per share)	(1.23)	(9.37)	3.10
Diluted income (loss) per share attributable to Belden common stockholders:
Continuing operations attributable to Belden common stockholders (in dollars per share)	1.21	2.15	3.23
Discontinued operations attributable to Belden common stockholders (in dollars per share)	(2.22)	(11.53)	(0.16)
Disposal of discontinued operations attributable to Belden common stockholders (in dollars per share)	(0.22)	0	0
Diluted income (loss) per share attributable to Belden stockholders:	$ (1.23)	$ (9.37)	$ 3.08

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 (loss)	$ (55,058)	$ (376,776)	$ 160,711
Foreign currency translation, net of tax of $1.0 million, $1.0 million, and $1.7 million, respectively	(112,562)	24,121	27,802
Adjustments to pension and postretirement liability, net of tax of $1.7 million, $1.1 million, and $1.0 million, respectively	(15,477)	(12,168)	(4,690)
Other comprehensive income (loss), net of tax	(128,039)	11,953	23,112
Comprehensive income (loss)	(183,097)	(364,823)	183,823
Less: Comprehensive income (loss) attributable to noncontrolling interest	498	703	(190)
Comprehensive income (loss) attributable to Belden	$ (183,595)	$ (365,526)	$ 184,013

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Foreign currency translation, tax expense (benefit)	$ 1	$ 1	$ 1.7
Adjustments to pension and postretirement liability, tax	$ 1.7	$ 1.1	$ 1

Consolidated Cash Flow Statemen

Consolidated Cash Flow Statements - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income (loss)	$ (55,058)	$ (376,776)	$ 160,711
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Asset impairment of discontinued operations	113,007	521,441	0
Depreciation and amortization	108,687	139,259	148,632
Share-based compensation	20,030	17,751	18,497
Loss on disposal of business	946	0	0
Loss on debt extinguishment	0	0	22,990
Deferred income tax expense (benefit)	(19,410)	(23,540)	11,300
Changes in operating assets and liabilities, net of the effects of exchange rate changes, acquired businesses, and disposals:
Receivables	70,707	22,926	(21,748)
Inventories	(8,507)	44,477	(14,779)
Accounts payable	(43,567)	(41,527)	(29,401)
Accrued liabilities	7,374	(17,654)	17,238
Income taxes	(22,823)	5,497	(4,390)
Other assets	2,018	(16,118)	(18,748)
Other liabilities	(40)	1,157	(1,082)
Net cash provided by operating activities	173,364	276,893	289,220
Cash flows from investing activities:
Capital expenditures	(90,215)	(110,002)	(97,847)
Cash from (used for) business acquisitions, net of cash acquired	590	(74,392)	(84,580)
Proceeds from disposal of tangible assets	3,161	25	1,580
Proceeds from disposal of business, net of cash sold	54,821	0	40,171
Net cash used for investing activities	(31,643)	(184,369)	(140,676)
Cash flows from financing activities:
Payments under borrowing arrangements	(190,000)	0	(484,757)
Payments under share repurchase program	(35,000)	(50,000)	(175,000)
Payment of earnout consideration	(29,300)	0	0
Cash dividends paid	(9,029)	(34,439)	(43,169)
Withholding tax payments for share based-payment awards	(1,388)	(2,149)	(2,094)
Other	(194)	(360)	0
Debt issuance costs paid	0	0	(7,609)
Redemption of stockholders' rights agreement	0	0	(411)
Borrowings under credit arrangements	190,000	0	431,270
Net cash used for financing activities	(74,911)	(86,948)	(281,770)
Effect of foreign currency exchange rate changes on cash and cash equivalents	9,299	(301)	(7,272)
Increase (decrease) in cash and cash equivalents	76,109	5,275	(140,498)
Cash and cash equivalents, beginning of year	425,885	420,610	561,108
Cash and cash equivalents, end of year	$ 501,994	$ 425,885	$ 420,610

Consolidated Stockholders' Equi

Consolidated Stockholders' Equity Statements - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Mandatory Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Retained EarningsCumulative Effect, Period of Adoption, Adjustment	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Non-controlling Interest
Beginning balance (in shares) at Dec. 31, 2017			52	50,335				8,316
Beginning balance at Dec. 31, 2017	$ 1,434,866		$ 1	$ 503	$ 1,123,832	$ 833,610		$ (425,685)	$ (98,026)	$ 631
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	160,711					160,894				(183)
Other comprehensive income (loss), net of tax	23,112								23,119	(7)
Exercise of stock options, net of tax withholding forfeitures	(765)				(883)			$ 118
Exercise of stock options, net of tax withholding forfeitures (in shares)								20
Conversion of restricted stock units into common stock, net of tax withholding forfeitures	(1,329)				(2,051)			$ 722
Conversion of restricted stock units into common stock, net of tax withholding forfeitures (in shares)								51
Share repurchase program	(175,000)							$ (175,000)
Share repurchase program (in shares)								(2,694)
Share-based compensation	18,497				18,497
Redemption of stockholders' rights agreement	(411)					(411)
Preferred stock dividends	(34,931)					(34,931)
Preferred stock dividends	(8,121)					(8,121)
Ending balance (in shares) at Dec. 31, 2018			52	50,335				10,939
Ending balance at Dec. 31, 2018	1,387,588	$ (29,041)	$ 1	$ 503	1,139,395	922,000	$ (29,041)	$ (599,845)	(74,907)	441
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(376,776)					(377,015)				239
Other comprehensive income (loss), net of tax	11,953								11,489	464
Acquisition of business with noncontrolling interests	5,195									5,195
Acquisition of noncontrolling interests	(765)				(398)					(367)
Exercise of stock options, net of tax withholding forfeitures	(111)				(291)			$ 180
Exercise of stock options, net of tax withholding forfeitures (in shares)								4
Conversion of restricted stock units into common stock, net of tax withholding forfeitures	(2,035)				(3,714)			$ 1,679
Conversion of restricted stock units into common stock, net of tax withholding forfeitures (in shares)								91
Share repurchase program	$ (50,000)							$ (50,000)
Share repurchase program (in shares)	(900)							(890)
Share-based compensation	$ 17,751				17,751
Redemption of stockholders' rights agreement	0
Preferred stock conversion (in shares)			(52)					6,857
Preferred stock conversion	0		$ (1)		(340,788)			$ 340,789
Preferred stock dividends	(18,437)					(18,437)
Preferred stock dividends	(8,544)					(8,544)
Ending balance (in shares) at Dec. 31, 2019			0	50,335				4,877
Ending balance at Dec. 31, 2019	965,819	$ (2,916)	$ 0	$ 503	811,955	518,004	$ (2,916)	$ (307,197)	(63,418)	5,972
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(55,058)					(55,162)				104
Other comprehensive income (loss), net of tax	(128,039)								(128,433)	394
Retirement Savings Plan stock contributions	2,654				(1,622)			$ 4,276
Retirement Savings Plan stock contributions (in shares)								76
Exercise of stock options, net of tax withholding forfeitures	(181)				(791)			$ 610
Exercise of stock options, net of tax withholding forfeitures (in shares)								7
Conversion of restricted stock units into common stock, net of tax withholding forfeitures	(1,208)				(5,967)			$ 4,759
Conversion of restricted stock units into common stock, net of tax withholding forfeitures (in shares)								78
Share repurchase program	$ (35,000)							$ (35,000)
Share repurchase program (in shares)	(1,000)							(976)
Share-based compensation	$ 20,030				20,030
Redemption of stockholders' rights agreement	0
Preferred stock dividends	(9,050)					(9,050)
Ending balance (in shares) at Dec. 31, 2020				50,335				5,692
Ending balance at Dec. 31, 2020	$ 757,051			$ 503	$ 823,605	$ 450,876		$ (332,552)	$ (191,851)	$ 6,470

Consolidated Stockholders' Eq_2

Consolidated Stockholders' Equity Statements (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Dividends declared per share	$ 0.20	$ 0.20	$ 0.20

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation Business Description Belden Inc. (the Company, us, we, or our) is a global supplier of specialty networking solutions built around two global business platforms – Enterprise Solutions and Industrial Solutions. Our comprehensive portfolio of solutions enables customers to transmit and secure data, sound, and video for mission critical applications across complex enterprise and industrial environments. Consolidation The accompanying Consolidated Financial Statements include Belden Inc. and all of its subsidiaries, including variable interest entities for which we are the primary beneficiary. We eliminate all significant affiliate accounts and transactions in consolidation. Foreign Currency For international operations with functional currencies other than the United States (U.S.) dollar, we translate assets and liabilities at current exchange rates; we translate income and expenses using average exchange rates. We report the resulting translation adjustments, as well as gains and losses from certain affiliate transactions, in accumulated other comprehensive income (loss), a separate component of stockholders’ equity. We include exchange gains and losses on transactions in operating income. We determine the functional currency of our foreign subsidiaries based upon the currency of the primary economic environment in which each subsidiary operates. Typically, that is determined by the currency in which the subsidiary primarily generates and expends cash. We have concluded that the local currency is the functional currency for all of our material subsidiaries. Reporting Periods Our fiscal year and fiscal fourth quarter both end on December 31. Our fiscal first quarter ends on the Sunday falling closest to 91 days after December 31. Our fiscal second and third quarters each have 91 days. Use of Estimates in the Preparation of the Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the U.S. requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, and operating results and the disclosure of contingencies. Actual results could differ from those estimates. We make significant estimates with respect to the collectability and valuation of receivables, the valuation of inventory, the realization of deferred tax assets, the valuation of goodwill and indefinite-lived intangible assets, the valuation of contingent liabilities, the calculation of share-based compensation, the calculation of pension and other postretirement benefits expense, and the valuation of acquired businesses. Reclassifications We have made certain reclassifications to the 2019 and 2018 Consolidated Financial Statements, primarily as a result of the West Penn Wire business and multi-conductor product line transfer from the Enterprise Solutions segment to the Industrial Solutions segment in 2020. See Note 6.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Fair Value Measurement Accounting guidance for fair value measurements specifies a hierarchy of valuation techniques based upon whether the inputs to those valuation techniques reflect assumptions other market participants would use based upon market data obtained from independent sources or reflect our own assumptions of market participant valuation. The hierarchy is broken down into three levels based on the reliability of the inputs as follows: • Level 1 – Quoted prices in active markets that are unadjusted and accessible at the measurement date for identical, unrestricted assets or liabilities; • Level 2 – Quoted prices for identical assets and liabilities in markets that are not active, quoted prices for similar assets and liabilities in active markets, or financial instruments for which significant inputs are observable, either directly or indirectly; and • Level 3 – Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable. During 2020, 2019, and 2018 we utilized Level 1 inputs to determine the fair value of cash equivalents and Level 2 and Level 3 inputs to determine the fair value of net assets acquired in business combinations (see Note 4) and for impairment testing (see Notes 5 and 13). We did not have any transfers between Level 1 and Level 2 fair value measurements during 2020. Cash and Cash Equivalents We classify cash on hand and deposits in banks, including commercial paper, money market accounts, and other investments with an original maturity of three months or less, that we hold from time to time, as cash and cash equivalents. We periodically have cash equivalents consisting of short-term money market funds and other investments. As of December 31, 2020 and 2019, we did not have any such cash equivalents on hand. The primary objective of our investment activities is to preserve our capital for the purpose of funding operations. We do not enter into investments for trading or speculative purposes. Accounts Receivable and Revenue Reserves We classify amounts owed to us and due within twelve months, arising from the sale of goods or services and from other business activities, as current receivables. We classify receivables due after twelve months as other long-lived assets. At the time of sale, we establish an estimated reserve for trade, promotion, and other special price reductions such as contract pricing, discounts to meet competitor pricing, and on-time payment discounts. We also adjust receivable balances for, among other things, correction of billing errors, incorrect shipments, and settlement of customer disputes. Customers are allowed to return inventory if and when certain conditions regarding the physical state of the inventory and our approval of the return are met. Certain distribution customers are allowed to return inventory at original cost, in an amount not to exceed three percent of the prior year’s purchases, in exchange for an order of equal or greater value. Until we can process these reductions, corrections, and returns (together, the Changes) through individual customer records, we estimate the amount of outstanding Changes and recognize them by reducing revenues. We base these estimates on historical and anticipated sales demand, trends in product pricing, and historical and anticipated Changes patterns. We make revisions to these estimates in the period in which the facts that give rise to each revision become known. Future market conditions might require us to take actions to further reduce prices and increase customer return authorizations. Unprocessed Changes recognized against our gross accounts receivable balance at December 31, 2020 and 2019 totale d $25.5 million and $29.5 million, respectively. Unprocessed Changes recognized as accrued liabilities at December 31, 2020 and 2019 totaled $13.0 million and $11.0 million, respectively. We are exposed to credit losses primarily through sales of products and services. Our expected loss allowance methodology for accounts receivable is developed using historical collection experience, current and future economic and market conditions and a review of the current status of customers' trade accounts receivables. Due to the short-term nature of such receivables, the estimate of amount of accounts receivable that may not be collected is based on aging of the accounts receivable balances and the financial condition of customers. Additionally, specific allowance amounts are established to record the appropriate provision for customers that have a higher probability of default. Our monitoring activities include timely account reconciliation, dispute resolution, payment confirmation, consideration of customers' financial condition and macroeconomic conditions. Balances are written off when determined to be uncollectible. As of December 31, 2020 and 2019, the allowance for doubtf ul accounts totaled $5.1 million and $2.6 million, respectively. We also recognized bad debt expense, net of recoveries, of $2.4 million, $0.1 million, and $0.2 million in 2020, 2019, and 2018, respectively. Inventories and Related Reserves Inventories are stated at the lower of cost or net realizable value. We determine the cost of all raw materials, work-in-process, and finished goods inventories by the first in, first out method. Cost components of inventories include direct labor, applicable production overhead, and amounts paid to suppliers of materials and products as well as freight costs and, when applicable, duty costs to import the materials and products. We evaluate the realizability of our inventory on a product-by-product basis in light of historical and anticipated sales demand, technological changes, product life cycle, component cost trends, product pricing, and inventory condition. In circumstances where inventory levels are in excess of anticipated market demand, where inventory is deemed technologically obsolete or not saleable due to condition, or where inventory cost exceeds net realizable value, we record a charge to cost of sales and reduce the inventory to its net realizable value. The allowances for excess and obsolete inventories at December 31, 2020 and 2019 totaled $32.3 million and $21.2 million, respectively. Property, Plant and Equipment We record property, plant and equipment at cost. We calculate depreciation on a straight-line basis over the estimated useful lives of the related assets ranging from 10 to 40 years for buildings, 5 to 12 years for machinery and equipment, and 5 to 10 years for computer equipment and software. Construction in process reflects amounts incurred for the configuration and build-out of property, plant and equipment and for property, plant and equipment not yet placed into service. We charge maintenance and repairs—both planned major activities and less-costly, ongoing activities—to expense as incurred. We capitalize interest costs associated with the construction of capital assets and amortize the costs over the assets’ useful lives. Depreciation expense is included in costs of sales; selling, general and administrative expenses; and research and development expenses in the Consolidated Statements of Operations based on the specific categorization and use of the underlying assets being depreciated. We review property, plant and equipment to determine whether an event or change in circumstances indicates the carrying values of the assets may not be recoverable. We base our evaluation on the nature of the assets, the future economic benefit of the assets, and any historical or future profitability measurements, as well as other external market conditions or factors that may be present. If such impairment indicators are present or other factors exist that indicate that the carrying amount of an asset may not be recoverable, we determine whether impairment has occurred through the use of an undiscounted cash flow analysis. If impairment has occurred, we recognize a loss for the difference between the carrying amount and the fair value of the asset. For purposes of impairment testing of long-lived assets, we have identified asset groups at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities. Generally, our asset groups are based on an individual plant or operating facility level. In some circumstances, however, a combination of plants or operating facilities may be considered the asset group due to interdependence of operational activities and cash flows. Goodwill and Intangible Assets Our intangible assets consist of (a) definite-lived assets subject to amortization such as developed technology, customer relationships, certain in-service research and development, certain trademarks, backlog, and capitalized software intangible assets, and (b) indefinite-lived assets not subject to amortization such as goodwill, certain trademarks, and certain in-process research and development intangible assets. We record amortization of the definite-lived intangible assets over the estimated useful lives of the related assets, which generally range from one year or less for backlog to more than 25 years for certain of our customer relationships. We determine the amortization method for our definite-lived intangible assets based on the pattern in which the economic benefits of the intangible asset are consumed. In the event we cannot reliably determine that pattern, we utilize a straight-line amortization method. We test our goodwill and other indefinite-lived intangible assets not subject to amortization for impairment on an annual basis as of our fiscal November month-end or when indicators of impairment exist. We base our estimates on assumptions we believe to be reasonable, but which are not predictable with precision and therefore are inherently uncertain. Actual future results could differ from these estimates. The accounting guidance related to goodwill impairment testing allows for the performance of an optional qualitative assessment of whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. Such an evaluation is made based on the weight of all available evidence and the significance of all identified events and circumstances that may influence the fair value of a reporting unit. If it is more likely than not that the fair value is less than the carrying value, then a quantitative assessment is required for the reporting u nit, as described in the paragraph below. In 2020, we did not perform a qualitative assessment over any of our reporting units. For our annual impairment test in 2020, we performed a quantitative assessment for all ten of our reporting units included in continuing operations. Under a quantitative assessment for goodwill impairment, we determine the fair value using the income approach (using Level 3 inputs) as reconciled to our aggregate market capitalization. Under the income approach, we calculate the fair value of a reporting unit based on the present value of estimated future cash flows. If the fair value of the reporting unit exceeds the carrying value of the net assets including goodwill assigned to that unit, goodwill is not impaired. If the carrying value of the reporting unit’s net assets including goodwill exceeds the fair value of the reporting unit, then we record an impairment charge based on that difference. In addition to the income approach, we calculate the fair value of our reporting units under a market approach. The market approach measures the fair value of a reporting unit through analysis of financial multiples of comparable businesses. Consideration is given to the financial conditions and operating performance of the reporting unit being valued relative to those publicly-traded companies operating in the same or similar lines of business. Based on our annual goodwill impairment test, the excess of the fair values over the carrying values of our ten reporting units tested under a quantitative income approach ranged from 4% - 345%. As a result, the goodwill balances for our continuing operations reporting units were not impaired in 2020. Furthermore, we did not recognize any goodwill impairment from continuing operations in 2019 or 2018. See Note 13 for further discussion. We also evaluate indefinite lived intangible assets for impairment annually or at other times if events have occurred or circumstances exist that indicate the carrying values of those assets may no longer be recoverable. We compare the fair value of the asset with its carrying amount. If the carrying amount of the asset exceeds its fair value, we recognize an impairment loss in an amount equal to that excess. We did not recognize impairment charges for our indefinite lived intangible assets from continuing operations in 2020, 2019, or 2018. See Note 13 for further discussion. We review intangible assets subject to amortization whenever an event or change in circumstances indicates the carrying values of the assets may not be recoverable. We test intangible assets subject to amortization for impairment and estimate their fair values using the same assumptions and techniques we employ on property, plant and equipment. We did not recognize any impairment charges for amortizable intangible assets from continuing operations in 2020, 2019, or 2018. Due to its overall financial performance and discontinued operations classification, we performed impairment tests on the Grass Valley disposal group, which resulted in total asset impairments of $113.0 million and $521.4 million in 2020 and 2019, respectively. The 2019 impairment charge consisted of impairments to goodwill, customer relationships, and trademarks of $326.1 million, $14.4 million, and $1.6 million, respectively, as well as an impairment of the disposal group of $179.3 million ($180.4 million translated at year-end exchange rates). We determined the estimated fair values of the assets and of the reporting unit by calculating the present values of their estimated future cash flows. Disposals During 2020, we sold a previously closed operating facility for net proceeds of $2.1 million and recognized a $0.4 million gain on the sale as well as completed the sale of Grass Valley to Black Dragon Capital - See Note 5. During 2018, we sold a previously closed operating facility for net proceeds of $1.5 million and recognized a $0.6 million gain on the sale. During 2017, we sold our MCS business and a 50% ownership interest in Xuzhou Hirschmann Electronics Co. Ltd (the Hirschmann JV) for a total purchase price of $40.2 million. The $40.2 million of proceeds from the sale was collected during 2018. Pension and Other Postretirement Benefits Our pension and other postretirement benefit costs and obligations are dependent on the various actuarial assumptions used in calculating such amounts. These assumptions relate to discount rates, salary growth, long-term return on plan assets, health care cost trend rates, mortality tables, and other factors. We base the discount rate assumptions on current investment yields on high-quality corporate long-term bonds. The salary growth assumptions reflect our long-term actual experience and future or near-term outlook. We determine the long-term return on plan assets based on historical portfolio results and management’s expectation of the future economic environment. Our health care cost trend assumptions are developed based on historical cost data, the near-term outlook, and an assessment of likely long-term trends. Actual results that differ from our assumptions are accumulated and, if in excess of the lesser of 10% of the projected benefit obligation or the fair market value of plan assets, are amortized over the estimated future working life of the plan participants. Accrued Sales Rebates We grant incentive rebates to participating customers as part of our sales programs. The rebates are determined based on certain targeted sales volumes. Rebates are paid quarterly or annually in either cash or receivables credits. Until we can process these rebates through individual customer records, we estimate the amount of outstanding rebates and recognize them as accrued liabilities and reductions in our gross revenues. We base our estimates on both historical and anticipated sales demand and rebate program participation. We charge revisions to these estimates back to accrued liabilities and revenues in the period in which the facts that give rise to each revision become known. Future market conditions and product transitions might require us to take actions to increase sales rebates offered, possibly resulting in an incremental increase in accrued liabilities and an incremental reduction in revenues at the time the rebate is offered. Accrued sales rebates at December 31, 2020 and 2019 totaled $32.2 million and $37.2 million, respectively. Contingent Liabilities We have established liabilities for environmental and legal contingencies that are probable of occurrence and reasonably estimable, the amounts of which are currently not material. A significant amount of judgment and use of estimates is required to quantify our ultimate exposure in these matters. We review the valuation of these liabilities on a quarterly basis, and we adjust the balances to account for changes in circumstances for ongoing and emerging issues. We accrue environmental remediation costs based on estimates of known environmental remediation exposures developed in consultation with our environmental consultants and legal counsel, the amounts of which are not currently material. We expense environmental compliance costs, which include maintenance and operating costs with respect to ongoing monitoring programs, as incurred. We evaluate the range of potential costs to remediate environmental sites. The ultimate cost of site clean-up is difficult to predict given the uncertainties of our involvement in certain sites, uncertainties regarding the extent of the required clean-up, the availability of alternative clean-up methods, variations in the interpretation of applicable laws and regulations, the possibility of insurance recoveries with respect to certain sites, and other factors. We are, from time to time, subject to routine litigation incidental to our business. These lawsuits primarily involve claims for damages arising out of the use of our products, allegations of patent or trademark infringement, and litigation and administrative proceedings involving employment matters and commercial disputes. Assessments regarding the ultimate cost of lawsuits require judgments concerning matters such as the anticipated outcome of negotiations, the number and cost of pending and future claims, and the impact of evidentiary requirements. Based on facts currently available, we believe the disposition of the claims that are pending or asserted will not have a materially adverse effect on our financial position, results of operations or cash flow. Business Combination Accounting We allocate the consideration of an acquired business to its identifiable assets and liabilities based on estimated fair values. The excess of the consideration over the amount allocated to the assets and liabilities, if any, is recorded to goodwill. We use all available information to estimate fair values. We typically engage third party valuation specialists to assist in the fair value determination of inventories, tangible long-lived assets, and intangible assets other than goodwill. The carrying values of acquired receivables and accounts payable have historically approximated their fair values as of the business combination date. As necessary, we may engage third party specialists to assist in the estimation of fair value for certain liabilities, such as deferred revenue or postretirement benefit liabilities. We adjust the preliminary acquisition accounting, as necessary, typically up to one year after the acquisition closing date as we obtain more information regarding asset valuations and liabilities assumed. Revenue Recognition We recognize revenue consistent with the principles as outlined in the following five step model: (1) identify the contract with the customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when (or as) each performance obligation is satisfied. See Note 3. Gain from Patent Litigation In 2011, the Company’s wholly-owned subsidiary, PPC, filed an action for patent infringement against Corning alleging that Corning infringed two of PPC’s patents. In 2015, a jury found that Corning willfully infringed both patents. Following a series of appeals, we received a pre-tax amount of approximately $62.1 million from Corning in 2018. We recorded the $62.1 million of cash received as a pre-tax gain from patent litigation during 2018. Cost of Sales Cost of sales includes our total cost of inventory sold during the period, including material, labor, production overhead costs, variable manufacturing costs, and fixed manufacturing costs. Production overhead costs include operating supplies, applicable utility expenses, maintenance costs, and scrap. Variable manufacturing costs include inbound, interplant, and outbound freight, inventory shrinkage, and charges for excess and obsolete inventory. Fixed manufacturing costs include the costs associated with our purchasing, receiving, inspection, warehousing, distribution centers, production and inventory control, and manufacturing management. Cost of sales also includes the costs to provide maintenance and support and other professional services. Shipping and Handling Costs We recognize fees earned on the shipment of product to customers as revenues and recognize costs incurred on the shipment of product to customers as a cost of sales. Selling, General and Administrative Expenses Selling, general and administrative expenses include expenses not directly related to the production of inventory. They include all expenses related to selling and marketing our products, as well as the salary and benefit costs of associates performing the selling and marketing functions. Selling, general and administrative expenses also include salary and benefit costs, purchased services, and other costs related to our executive and administrative functions. Research and Development Costs Research and development costs are expensed as incurred. Advertising Costs Advertising costs are expensed as incurred. Advertising costs w ere $11.6 million , $14.7 million, and $17.0 million for 2020, 2019, and 2018, respectively. Share-Based Compensation We compensate certain employees and non-employee directors with various forms of share-based payment awards and recognize compensation costs for these awards based on their fair values. We estimate the fair values of certain awards, primarily stock appreciation rights (SARs), on the grant date using the Black-Scholes-Merton option-pricing formula, which incorporates certain assumptions regarding the expected term of an award and expected stock price volatility. We develop the expected term assumption based on the vesting period and contractual term of an award, our historical exercise and cancellation experience, our stock price history, plan provisions that require exercise or cancellation of awards after employees terminate, and the extent to which currently available information indicates that the future is reasonably expected to differ from past experience. We develop the expected volatility assumption based on historical price data for our common stock. We estimate the fair value of certain restricted stock units with service vesting conditions and performance vesting conditions based on the grant date stock price. We estimate the fair value of certain restricted stock units with market conditions using a Monte Carlo simulation valuation model with the assistance of a third party valuation firm. After calculating the aggregate fair value of an award, we use an estimated forfeiture rate to discount the amount of share-based compensation cost expected to be recognized in our operating results over the service period of the award. We develop the forfeiture assumption based on our historical pre-vesting cancellation experience. Income Taxes Income taxes are provided based on earnings reported for financial statement purposes. The provision for income taxes differs from the amounts currently payable to taxing authorities because of the recognition of revenues and expenses in different periods for income tax purposes than for financial statement purposes. Income taxes are provided as if operations in all countries, including the U.S., were stand-alone businesses filing separate tax returns. We recognize deferred tax assets resulting from tax credit carryforwards, net operating loss carryforwards, and deductible temporary differences between taxable income on our income tax returns and pretax income on our financial statements. Deferred tax assets generally represent future tax benefits to be received when these carryforwards can be applied against future taxable income or when expenses previously reported in our Consolidated Financial Statements become deductible for income tax purposes. A deferred tax asset valuation allowance is required when some portion or all of the deferred tax assets may not be realized. At December 31, 2020 the valuation allowance of $84.3 million was primarily related to net operating losses, capital losses and foreign tax credits that we do not expect to realize. Our effective tax rate is based on expected income, statutory tax rates, and tax planning opportunities available to us in the various jurisdictions in which we operate. Significant judgment is required in determining our effective tax rate and in evaluating our tax positions. We establish accruals for uncertain tax positions when we believe that the full amount of the associated tax benefit may not be realized. To the extent we were to prevail in matters for which accruals have been established or would be required to pay amounts in excess of reserves, there could be a material effect on our income tax provisions in the period in which such determination is made. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740) Simplifying the Accounting for Income Taxes (“ASU 2019-12”) which removes certain exceptions for investments, intra-period allocations and interim tax calculations, and adds guidance to reduce the complexity in accounting for income taxes. ASU 2019-12 is effective for annual periods beginning after December 15, 2020, with early adoption permitted. The various amendments in ASU 2019-12 are applied on a retrospective basis, modified retrospective basis and prospective basis, depending upon the amendment. The Company did not early adopt this pronouncement and is in the process of evaluating the impact of this amendment on our consolidated financial statements; however, it is not anticipated to be material. See Note 18, Income Taxes, in the accompanying notes to our consolidated financial statements. Current-Year Adoption of Accounting Pronouncements In June 2016, the FASB issued Accounting Standards Update No. 2016-13 (“ASU 2016-13”), Financial Instruments - Credit Losses . Under the new standard, we are required to recognize estimated credit losses expected to occur over the estimated life or remaining contractual life of an asset (which includes losses that may be incurred in future periods) using a broader range of information including past events, current conditions, and reasonable and supportable forecasts about future economic conditions. We adopted ASU 2016-13 on January 1, 2020, which resulted in an increase to our allowance for doubtful accounts for continuing operations of $1.0 million, and an increase for discontinued operations of $1.9 million. See further discussion as well as adjustments to the allowance for doubtful accounts under the new credit loss model in Note 9.

Revenues

Revenues	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenues	Revenues On January 1, 2018, we adopted Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) using the modified retrospective method applied to those contracts which were not completed as of January 1, 2018. We recorded a net increase to retained earnings of $2.6 million as of January 1, 2018 due to the cumulative impact of adopting Topic 606, with the impact primarily related to sales commissions and software revenues within our Industrial Solutions segment. Revenues are recognized when control of the promised goods or services is transferred to our customers and in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. Taxes collected from customers and remitted to governmental authorities are not included in our revenues. We do not evaluate a contract for a significant financing component when the time between cash collection and performance is less than one year. The following table presents our revenues disaggregated by major product category (in thousands). Broadband and 5G Cyber-Security Industrial Automation Smart Buildings Total Year Ended December 31, 2020 Enterprise Solutions $ 432,262 $ — $ — $ 440,155 $ 872,417 Industrial Solutions — 110,524 879,775 — 990,299 Total $ 432,262 $ 110,524 $ 879,775 $ 440,155 $ 1,862,716 Year Ended December 31, 2019 Enterprise Solutions $ 401,415 $ — $ — $ 544,626 $ 946,041 Industrial Solutions — 133,039 1,052,198 — 1,185,237 Total $ 401,415 $ 133,039 $ 1,052,198 $ 544,626 $ 2,131,278 Year Ended December 31, 2018 Enterprise Solutions $ 389,246 $ — $ — $ 568,255 $ 957,501 Industrial Solutions — 136,648 1,071,553 — 1,208,201 Total $ 389,246 $ 136,648 $ 1,071,553 $ 568,255 $ 2,165,702 The following tables present our revenues disaggregated by geography, based on the location of the customer purchasing the product (in thousands). Americas EMEA APAC Total Revenues Year Ended December 31, 2020 Enterprise Solutions $ 636,492 $ 130,982 $ 104,943 $ 872,417 Industrial Solutions 577,929 256,673 155,697 990,299 Total $ 1,214,421 $ 387,655 $ 260,640 $ 1,862,716 Year Ended December 31, 2019 Enterprise Solutions $ 695,008 $ 135,732 $ 115,301 $ 946,041 Industrial Solutions 742,563 274,030 168,644 1,185,237 Total $ 1,437,571 $ 409,762 $ 283,945 $ 2,131,278 Year Ended December 31, 2018 Enterprise Solutions $ 700,499 $ 135,217 $ 121,785 $ 957,501 Industrial Solutions 758,165 290,562 159,474 1,208,201 Total $ 1,458,664 $ 425,779 $ 281,259 $ 2,165,702 We generate revenues primarily by selling products that provide secure and reliable transmission of data, sound, and video for mission critical applications. We also generate revenues from providing support and professional services. We sell our products to distributors, end-users, installers, and directly to original equipment manufacturers. At times, we enter into arrangements that involve the delivery of multiple performance obligations. For these arrangements, revenue is allocated to each performance obligation based on its relative standalone selling price and recognized when or as each performance obligation is satisfied. Most of our performance obligations related to the sale of products are satisfied at a point in time when control of the product is transferred based on the shipping terms of the arrangement. Generally, we determine standalone selling price using the prices charged to customers on a standalone basis. Typically, payments are due after control transfers, which is less than one year from satisfaction of the performance obligation. The amount of consideration we receive and revenue we recognize varies due to rebates, returns, and price adjustments. We estimate the expected rebates, returns, and price adjustments based on an analysis of historical experience, anticipated sales demand, and trends in product pricing. We adjust our estimate of revenue at the earlier of when the most likely amount of consideration we expect to receive changes or when the consideration becomes fixed. Adjustments to revenue for performance obligations satisfied in prior periods was not significant during the year ended December 31, 2020. The following table presents estimated and accrued variable consideration: December 31, 2020 December 31, 2019 (in thousands) Accrued rebates $ 32,192 $ 37,170 Accrued returns 13,016 10,974 Price adjustment recognized against gross accounts receivable 25,244 28,672 Depending on the terms of an arrangement, we may defer the recognition of a portion of the consideration received because we have to satisfy a future obligation. Consideration allocated to support services under a support and maintenance contract is typically paid in advance and recognized ratably over the term of the service. The typical use of a time-elapsed unit of measure for support and maintenance contracts reflects the benefit and same pattern of transfer the customer receives from our services under this arrangement over the term of the contract. Consideration allocated to professional services is recognized when or as the services are performed depending on the terms of the arrangement. As of December 31, 2020, total deferred revenue was $77.6 million, and of this amount, $53.4 million is expected to be recognized within the next twelve months, and the remaining $24.2 million is long-term and will be recognized over a period greater than twelve months. The following table presents deferred revenue activity (in thousands): Balance at December 31, 2018 $ 72,358 New deferrals 111,812 Revenue recognized (114,100) Balance at December 31, 2019 $ 70,070 New deferrals 101,066 Revenue recognized (93,488) Balance at December 31, 2020 $ 77,648 Service-type warranties represent $10.4 million of the deferred revenue balance at December 31, 2020, and of this amount $3.6 million is expected to be recognized in the next twelve months, and the remaining $6.8 million is long-term and will be recognized over a period greater than twelve months. We expense sales commissions as incurred when the duration of the related revenue arrangement is one year or less. We capitalize sales commissions in other current and long-lived assets on our balance sheet when the duration of the related revenue arrangement is longer than one year, and we amortize it over the related revenue arrangement period. Total capitalized sales commissions were $5.8 million, $3.4 million, and $2.9 million as of December 31, 2020, 2019, and 2018, respectively. For the years ended December 31, 2020, 2019 and 2018, we recogn

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Acquisitions	Acquisitions Special Product Company On December 6, 2019, we purchased and assumed substantially all the assets, and certain specified liabilities of Special Product Company (SPC) for a purchase price of $22.5 million. SPC, based in Kansas City, Kansas, is a leading designer, manufacturer, and seller of outdoor cabinet products for optical fiber cable installations. The results of SPC have been included in our Consolidated Financial Statements from December 6, 2019, and are reported within the Enterprise Solutions segment. The acquisition of SPC was not material to our financial position or results of operations. Opterna We acquired 100% of the shares of Opterna International Corp. (Opterna) on April 15, 2019 for a purchase price, net of cash acquired, of $51.7 million. Of the $51.7 million purchase price, $45.9 million was paid in 2019 with cash on hand. The acquisition included a potential earnout, which is based upon future Opterna financial targets through April 15, 2021. The maximum earnout consideration is $25.0 million, but based upon a third party valuation specialist using certain assumptions in a discounted cash flow model, the estimated fair value of the earnout included in the purchase price is $5.8 million. Opterna is an international fiber optics solution business formerly based in Sterling, Virginia which designs and manufactures a range of complementary fiber connectivity, cabinet, and enclosure products used in optical networks. The results of Opterna have been included in our Consolidated Financial Statements from April 15, 2019, and are reported within the Enterprise Solutions segment. Certain subsidiaries of Opterna include noncontrolling interests. Because Opterna has a controlling financial interest in these subsidiaries, they are consolidated into our financial statements. The results that are attributable to the noncontrolling interest holders are presented as net income attributable to noncontrolling interests in the Consolidated Statements of Operations. An immaterial amount of Opterna's annual revenues are generated from transactions with the noncontrolling interests. On October 25, 2019, we purchased the noncontrolling interest of one subsidiary for a purchase price of $0.8 million; of which $0.4 million was paid at closing and the remaining $0.4 million is to be paid in 2021. The following table summarizes the estimated fair values of the assets acquired and the liabilities assumed as of April 15, 2019 (in thousands): Receivables $ 5,308 Inventory 7,359 Prepaid and other current assets 566 Property, plant, and equipment 1,328 Intangible assets 28,000 Goodwill 35,057 Deferred income taxes 80 Operating lease right-of-use assets 2,204 Other long-lived assets 2,070 Total assets acquired $ 81,972 Accounts payable $ 4,847 Accrued liabilities 4,301 Long-term deferred tax liability 6,813 Long-term operating lease liability 1,923 Other long-term liabilities 7,152 Total liabilities assumed $ 25,036 Net assets $ 56,936 Noncontrolling interest 5,195 Net assets attributable to Belden $ 51,741 The fair value of acquired receivables is $5.3 million, which is equivalent to its gross contractual amount. A single estimate of fair value results from a complex series of judgments about future events and uncertainties and relies heavily on estimates and assumptions. The judgments we have used in estimating the preliminary fair value assigned to each class of acquired assets and assumed liabilities could materially affect the results of our operations. We did not record any material measurement-period adjustments during 2020. For the purpose of the above allocation, we based our estimate of fair value for the acquired inventory, intangible assets, and noncontrolling interests on valuation studies performed by a third party valuation firm. We have estimated a fair value adjustment for inventories based on the estimated selling price of the work-in-process and finished goods acquired at the closing date less the sum of the costs to complete the work-in-process, the costs of disposal, and a reasonable profit allowance for post acquisition selling efforts. We used various valuation methods including discounted cash flows, lost income, excess earnings, and relief from royalty to estimate the fair value of the identifiable intangible assets (Level 3 valuation). Goodwill and other intangible assets reflected above were determined to meet the criteria for recognition apart from tangible assets acquired and liabilities assumed. The goodwill is primarily attributable to expansion of product offerings in the optical fiber market. Our tax basis in the acquired goodwill is zero. The intangible assets related to the acquisition consisted of the following: Fair Value Amortization Period (In thousands) (In years) Intangible assets subject to amortization Developed technologies $ 3,400 5 Customer relationships 22,800 15 Sales backlog 1,300 0.5 Trademarks 500 2.0 Total intangible assets subject to amortization $ 28,000 Intangible assets not subject to amortization: Goodwill $ 35,057 Total intangible assets not subject to amortization $ 35,057 Total intangible assets $ 63,057 Weighed average amortization period 12.9 The amortizable intangible assets reflected in the table above were determined by us to have finite lives. The useful life for the developed technology intangible asset was based on the estimated time that the technology provides us with a competitive advantage and thus approximates the period and pattern of consumption of the intangible asset. The useful life for the customer relationship intangible asset was based on our forecasts of estimated sales from recurring customers. The useful life of the backlog intangible asset was based on our estimate of when the ordered items would ship and control of the items transfers. The useful life for the trademarks was based on the period of time we expect to continue to go to market using the trademarks. The following table illustrates the unaudited pro forma effect on operating results as if the Opterna acquisition had been completed January 1, 2018. Years Ended December 31, 2019 2018 (In thousands, except per share data) (Unaudited) Revenues $ 2,139,894 $ 2,213,781 Net income (loss) attributable to Belden common stockholders (389,957) 123,546 Diluted income (loss) per share attributable to Belden common stockholders $ (9.24) $ 3.02 For purposes of the pro forma disclosures, the year ended December 31, 2018 includes expenses related to the acquisition, including severance, restructuring, and acquisition costs; amortization of intangible assets; and cost of sales arising from the adjustment of inventory to fair value of $5.5 million, $3.8 million, and $0.5 million, respectively. The above unaudited pro forma information is presented for information purposes only and does not purport to represent what our results of operations would have been had we completed the acquisition on the date assumed, nor is it necessarily indicative of the results that may be expected in future periods. Pro forma adjustments exclude cost savings from any synergies resulting from the acquisition. FutureLink

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2020
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Discontinued Operations We classify assets and liabilities as held for sale (disposal group) when management, having the authority to approve the action, commits to a plan to sell the disposal group, the sale is probable within one year, and the disposal group is available for immediate sale in its present condition. We also consider whether an active program to locate a buyer has been initiated, whether the disposal group is marketed actively for sale at a price that is reasonable in relation to its current fair value, and whether actions required to complete the plan indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. During the fourth quarter of 2019, we committed to a plan to sell Grass Valley, and at such time, met all of the criteria to classify the assets and liabilities of this business as held for sale. Furthermore, we determined a divestiture of Grass Valley represents a strategic shift that is expected to have a major impact on our operations and financial results. As a result, the Grass Valley disposal group, which was included in our Enterprise Solutions segment, is reported within discontinued operations. The Grass Valley disposal group excludes certain Grass Valley pension liabilities that Belden retained. We also ceased depreciating and amortizing the assets of the disposal group once they met the held for sale criteria in the fourth quarter of 2019. We wrote down the carrying value of Grass Valley and recognized asset impairments totaling $113.0 million and $521.4 million in 2020 and 2019, respectively. The 2019 impairment charge consisted of impairments to goodwill, customer relationships, and trademarks of $326.1 million, $14.4 million, and $1.6 million, respectively, as well as an impairment of the disposal group of $179.3 million ($180.4 million translated at year-end exchange rates). We determined the estimated fair values of the assets and of the reporting unit by calculating the present values of their estimated future cash flows. We completed the sale of Grass Valley to Black Dragon Capital on July 2, 2020 and recognized a loss of $9.9 million, net of $7.5 million income tax expense. The terms of the sale included gross cash consideration of $120.0 million, or approximately $56.2 million net of cash delivered with the business. The sale also included deferred consideration consisting of a $175.0 million seller’s note that is expected to mature in 2025, up to $88 million in PIK (payment-in-kind) interest on the seller’s note, and $178.0 million in potential earnout payments. Based upon a third party valuation specialist using certain assumptions in a Monte Carlo analysis, the estimated fair value of the seller’s note is $34.9 million, which we recorded in Other Long-Lived Assets. We accounted for the earnout under a loss recovery approach and did not record an asset as of the disposal date. Any subsequent recognition of an earnout will be based on the gain contingency guidance. As part of the transaction, we also invested $3.0 million for a 9% equity interest in Grass Valley with the right to put the equity back to Black Dragon Capital. We exercised our right during the fourth quarter of 2020 and sold our 9% equity interest in Grass Valley to Black Dragon Capital for $2.7 million. We deconsolidated Grass Valley as of July 2, 2020 and accounted for our equity interest under the cost method for the period that we owned a 9% interest in Grass Valley. As of December 31, 2020, we do not own any interest in Grass Valley. Grass Valley's operating results for periods after July 2, 2020 are not included in our Consolidated Financial Statements. The seller’s note accrues PIK interest at an annual rate of 8.5%. During the year ended December 31, 2020, the seller’s note accrued interest of $7.8 million, which we reserved for based on our expected loss allowance methodology. We are performing certain services for Grass Valley under a transition services agreement. During 2020, the amount of transition services totaled $2.0 million, which we expect to collect in 2021. The following table summarizes the operating results of the disposal group up to the July 2, 2020 disposal date for the years ended December 31, 2020, 2019 and 2018, respectively: Years Ended December 31, 2020 2019 2018 (In thousands) Revenues $ 109,195 $ 360,496 $ 419,666 Cost of sales (70,199) (208,173) (241,164) Gross profit 38,996 152,323 178,502 Selling, general and administrative expenses (39,947) (93,796) (114,567) Research and development expenses (15,083) (37,172) (49,033) Amortization of intangibles — (12,782) (23,689) Asset impairment of discontinued operations (113,007) (521,441) — Interest expense, net (432) (819) (720) Non-operating pension cost (169) (221) (243) Loss before taxes $ (129,642) $ (513,908) $ (9,750) The disposal group recognized depreciation and amortization expense of approximately $0.0 million, $23.7 million, and $35.1 million during the years ended December 31, 2020, 2019, and 2018, respectively. The disposal group also had capital expenditures of approximately $16.7 million, $29.4 million, and $22.6 million during the years ended December 31, 2020, 2019, and 2018, respectively. Furthermore, the disposal group incurred stock-based compensation expense/(credits) of $(0.9) million, $0.9 million, and $1.4 million during the years ended December 31, 2020, 2019, and 2018, respectively. The disposal group did not have any significant non-cash charges for investing activities during the years ended December 31, 2020, 2019, and 2018. The following table provides the major classes of assets and liabilities of the disposal group as of December 31, 2019 (in thousands): Assets: Cash and cash equivalents $ 18,405 Receivables, net 117,386 Inventories, net 55,002 Other current assets 35,187 Property, plant and equipment, less accumulated depreciation 61,233 Operating lease right-of-use assets 16,902 Goodwill 26,707 Intangible assets, less accumulated amortization 143,459 Deferred income taxes 59,560 Other long-lived assets 21,652 Impairment of disposal group (180,358) Total assets of discontinued operations $ 375,135 Liabilities: Accounts payable $ 52,425 Accrued liabilities 83,349 Postretirement benefits 6,224 Deferred income taxes 2,740 Long-term operating lease liabilities 20,459 Other long-term liabilities 5,082 Total liabilities of discontinued operations $ 170,279 The disposal group also had $42.3 million of accumulated other comprehensive losses as of December 31, 2019.

Operating Segments and Geograph

Operating Segments and Geographic Information	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Operating Segments and Geographic Information	Operating Segments and Geographic Information We are organized around two global business platforms: Enterprise Solutions and Industrial Solutions. Each of the global business platforms represents a reportable segment. Effective January 1, 2020, we transferred our West Penn Wire business and multi-conductor product lines from the Enterprise Solutions segment to the Industrial Solutions segment as a result of a shift in responsibilities among the segments. We have recast the prior period segment information to conform to the change in the composition of reportable segments. The segments design, manufacture, and market a portfolio of signal transmission solutions for mission critical applications used in a variety of end markets. We sell the products manufactured by our segments through distributors or directly to systems integrators, original equipment manufacturers (OEMs), end-users, and installers. The key measures of segment profit or loss reviewed by our chief operating decision maker are Segment Revenues and Segment EBITDA. Segment Revenues represent non-affiliate revenues and include revenues that would have otherwise been recorded by acquired businesses as independent entities but were not recognized in our Consolidated Statements of Operations due to the effects of purchase accounting and the associated write-down of acquired deferred revenue to fair value. Segment EBITDA excludes certain items, including depreciation expense; amortization of intangibles; asset impairment; severance, restructuring, and acquisition integration costs; purchase accounting effects related to acquisitions, such as the adjustment of acquired inventory and deferred revenue to fair value; and other costs. We allocate corporate expenses to the segments for purposes of measuring Segment EBITDA. Corporate expenses are allocated on the basis of each segment’s relative EBITDA prior to the allocation. Our measure of segment assets does not include cash, goodwill, intangible assets, deferred tax assets, or corporate assets. All goodwill is allocated to reporting units of our segments for purposes of impairment testing. Operating Segment Information Enterprise Solutions Years ended December 31, 2020 2019 2018 (In thousands) Segment revenues $ 872,415 $ 946,041 $ 957,501 Affiliate revenues 1,289 4,162 6,105 Segment EBITDA 99,333 126,925 156,790 Depreciation expense 20,655 19,771 18,490 Amortization of intangibles 21,662 22,324 21,076 Amortization of software development intangible assets 245 175 71 Severance, restructuring, and acquisition integration costs 7,720 10,808 14,863 Purchase accounting effects of acquisitions 125 592 1,690 Acquisition of property, plant and equipment 25,223 42,289 42,624 Segment assets 462,615 487,125 430,128 Industrial Solutions Years ended December 31, 2020 2019 2018 (In thousands) Segment revenues $ 990,301 $ 1,185,237 $ 1,208,201 Affiliate revenues 60 11 80 Segment EBITDA 147,626 226,110 237,870 Depreciation expense 21,815 20,638 19,819 Amortization of intangibles 42,733 52,285 54,064 Amortization of software development intangible assets 1,576 350 8 Severance, restructuring, and acquisition integration costs 4,538 15,736 7,762 Acquisition of property, plant and equipment 44,675 35,189 29,529 Segment assets 522,637 504,482 508,843 Total Segments Years ended December 31, 2020 2019 2018 (In thousands) Segment revenues $ 1,862,716 $ 2,131,278 $ 2,165,702 Affiliate revenues 1,349 4,173 6,185 Segment EBITDA 246,959 353,035 394,660 Depreciation expense 42,470 40,409 38,309 Amortization of intangibles 64,395 74,609 75,140 Amortization of software development intangible assets 1,821 525 79 Severance, restructuring, and acquisition integration costs 12,258 26,544 22,625 Purchase accounting effects of acquisitions 125 592 1,690 Acquisition of property, plant and equipment 69,898 77,478 72,153 Segment assets 985,252 991,607 938,971 The following table is a reconciliation of the total of the reportable segments’ Revenues and EBITDA to consolidated revenues and consolidated income from continuing operations before taxes, respectively. Years Ended December 31, 2020 2019 2018 (In thousands) Total Segment Revenues $ 1,862,716 $ 2,131,278 $ 2,165,702 Deferred revenue adjustments — — — Consolidated Revenues $ 1,862,716 $ 2,131,278 $ 2,165,702 Total Segment EBITDA $ 246,959 $ 353,035 $ 394,660 Amortization of intangibles (64,395) (74,609) (75,140) Depreciation expense (42,470) (40,409) (38,309) Severance, restructuring, and acquisition integration costs (1) (12,258) (26,544) (22,625) Purchase accounting effects related to acquisitions (2) (125) (592) (1,690) Amortization of software development intangible assets (1,821) (525) (79) Loss on sale of assets (3) — — (94) Costs related to patent litigation — — (2,634) Gain from patent litigation — — 62,141 Eliminations (480) (3,149) (2,222) Consolidated operating income 125,410 207,207 314,008 Interest expense, net (58,888) (55,814) (60,839) Non-operating pension benefit (cost) (395) 1,017 (99) Loss on debt extinguishment — — (22,990) Consolidated income from continuing operations before taxes $ 66,127 $ 152,410 $ 230,080 (1) See Note 15, Severance, Restructuring, and Acquisition Integration Activities, for details . (2) In 2020 and 2019, we collectively recognized $0.1 million and $0.6 million, respectively, of cost of sales related to purchase accounting adjustments of acquired inventory to fair value for both our SPC and Opterna acquisitions. In 2018, we made a $1.7 million adjustment to increase the earn-out liability associated with an acquisition. (3) In 2018, we recognized a $0.1 million loss on sale of assets for the sale of our MCS business and Hirschmann JV. See Note 2. Below are reconciliations of other segment measures to the consolidated totals. Years Ended December 31, 2020 2019 2018 (In thousands) Total segment assets $ 985,252 $ 991,607 $ 938,971 Cash and cash equivalents 501,994 407,480 407,454 Goodwill 1,251,938 1,243,669 1,206,877 Intangible assets, less accumulated amortization 287,071 339,505 359,931 Deferred income taxes 29,536 25,216 26,459 Corporate assets 83,943 24,147 16,786 Assets of discontinued operations — 375,135 822,843 Total assets $ 3,139,734 $ 3,406,759 $ 3,779,321 Total segment acquisition of property, plant and equipment $ 69,898 $ 77,478 $ 72,153 Discontinued operations acquisition of property, plant and equipment 16,712 29,414 22,681 Corporate acquisition of property, plant and equipment 3,605 3,110 3,013 Total acquisition of property, plant and equipment $ 90,215 $ 110,002 $ 97,847 Geographic Information The Company attributes foreign sales based on the location of the customer purchasing the product. The table below summarizes net sales and long-lived assets for the years ended December 31, 2020, 2019 and 2018 for the following countries: the U.S., Canada, China, and Germany. No other individual foreign country’s net sales or long-lived assets are material to the Company. United Canada China Germany All Other Total (In thousands, except percentages) Year ended December 31, 2020 Revenues $ 1,015,340 $ 119,700 $ 111,835 $ 91,187 $ 524,654 $ 1,862,716 Percent of total revenues 55 % 6 % 6 % 5 % 28 % 100 % Long-lived assets $ 163,731 $ 32,063 $ 44,824 $ 63,100 $ 114,286 $ 418,004 Year ended December 31, 2019 Revenues $ 1,167,033 $ 162,975 $ 109,522 $ 92,913 $ 598,835 $ 2,131,278 Percent of total revenues 55 % 8 % 5 % 4 % 28 % 100 % Long-lived assets $ 152,214 $ 16,452 $ 40,247 $ 48,272 $ 101,179 $ 358,364 Year ended December 31, 2018 Revenues $ 1,206,401 $ 166,669 $ 107,582 $ 100,691 $ 584,359 $ 2,165,702 Percent of total revenues 56 % 8 % 5 % 4 % 27 % 100 % Long-lived assets $ 170,368 $ 13,352 $ 36,989 $ 39,724 $ 63,776 $ 324,209 Major Customer Revenues generated in both the Enterprise Solutions and Industrial Solutions segments from sales to WESCO were approximately $271.6 million (15% of revenues), $328.2 million (15% of revenues), and $361.7 million (17% of revenues) for 2020, 2019, and 2018, respectively. At December 31, 2020, we had $17.5 million in accounts receivable outstanding from WESCO, which represented approximately 6% of our total accounts receivable outstanding at December 31, 2020.

Noncontrolling Interest

Noncontrolling Interest	12 Months Ended
	Dec. 31, 2020
Noncontrolling Interest [Abstract]
Noncontrolling Interest	Noncontrolling Interest We have a 51% ownership percentage in a joint venture with Shanghai Hi-Tech Control System Co, Ltd (Hite). The purpose of the joint venture is to develop and provide certain Industrial Solutions products and integrated solutions to customers in China. Belden and Hite are committed to fund $1.53 million and $1.47 million, respectively, to the joint venture in the future. The joint venture is determined to not have sufficient equity at risk; therefore, it is considered a variable interest entity. We have determined that Belden is the primary beneficiary of the joint venture, due to both our ownership percentage and our control over the activities of the joint venture that most significantly impact its economic performance based on the terms of the joint venture agreement with Hite. Because Belden is the primary beneficiary of the joint venture, we have consolidated the joint venture in our financial statements. The results of the joint venture attributable to Hite’s ownership are presented as net income (loss) attributable to noncontrolling interest in the Consolidated Statements of Operations. The joint venture is not material to our consolidated financial statements as of or for the years ended December 31, 2020, 2019, or 2018. We acquired Opterna in April 2019. Certain subsidiaries of Opterna include noncontrolling interests. Because we have a controlling financial interest in these subsidiaries, they are consolidated into our financial statements. The results of these subsidiaries were consolidated into our financial statements as of the acquisition date. The results that are attributable to the noncontrolling interest holders are presented as net income (loss) attributable to noncontrolling interests in the Consolidated Statements of Operations. An immaterial amount of Opterna's annual revenues are generated from transactions with the noncontrolling interests. On October 25, 2019, we purchased the noncontrolling interest of one subsidiary for a purchase price of $0.8 million; of which $0.4 million was paid at closing and the remaining $0.4 million will be paid in 2021. The subsidiaries of Opterna that include noncontrolling interests are not material to our consolidated financial statements as of or for the years ended December 31, 2020, 2019 or 2018.

Income Per Share

Income Per Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Income Per Share	Income Per Share The following table presents the basis of the income per share computations: Years Ended December 31, 2020 2019 2018 (In thousands) Numerator: Income from continuing operations $ 54,403 $ 109,891 $ 167,144 Less: Net income (loss) attributable to noncontrolling interest 104 239 (183) Less: Preferred stock dividends — 18,437 34,931 Income from continuing operations attributable to Belden common stockholders 54,299 91,215 132,396 Add: Loss from discontinued operations, net of tax (99,513) (486,667) (6,433) Add: Loss on disposal of discontinued operations, net of tax (9,948) — — Net income (loss) attributable to Belden common stockholders $ (55,162) $ (395,452) $ 125,963 Denominator: Weighted average shares outstanding, basic 44,778 42,203 40,675 Effect of dilutive common stock equivalents 159 213 281 Weighted average shares outstanding, diluted 44,937 42,416 40,956 Basic weighted average shares outstanding is used to calculate diluted loss per share when the numerator is a loss because using diluted weighted average shares outstanding would be anti-dilutive. For the years ended December 31, 2020, 2019, and 2018, diluted weighted average shares outstanding exclude outstanding equity awards of 1.5 million, 1.2 million, and 0.9 million, respectively, which are anti-dilutive. In addition, for the years ended December 31, 2020, 2019, and 2018, diluted weighted average shares outstanding do not include outstanding equity awards of 0.4 million, 0.3 million, and 0.3 million, respectively, because the related performance conditions have not been satisfied. Furthermore, for t he years ended December 31, 2019, and 2018, diluted weighted average shares outstanding do not include the weighted average impact of preferred shares that were convertible into 3.7 million and 6.9 million common shares, respectively, because deducting the preferred stock dividends from net income was more dilutive. For purposes of calculating basic earnings per share, unvested restricted stock units are not included in the calculation of basic weighted average shares outstanding until all necessary conditions have been satisfied and issuance of the shares underlying the restricted stock units is no longer contingent. Necessary conditions are not satisfied until the vesting date, at which time holders of our restricted stock units receive shares of our common stock. For purposes of calculating diluted earnings per share, unvested restricted stock units are included to the extent that they are dilutive. In determining whether unvested restricted stock units are dilutive, each issuance of restricted stock units is considered separately. Once a restricted stock unit has vested, it is included in the calculation of both basic and diluted weighted average shares outstanding.

Credit Losses

Credit Losses	12 Months Ended
	Dec. 31, 2020
Credit Loss [Abstract]
Credit Loss	Credit Losses Effective January 1, 2020, we adopted ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments prospectively. This ASU replaces the incurred loss impairment model with an expected credit loss impairment model for financial instruments, including trade receivables. The amendment requires entities to consider forward-looking information to estimate expected credit losses, resulting in earlier recognition of losses for receivables that are current or not yet due, which were not considered under the previous accounting guidance. Upon adoption, we recorded a noncash cumulative effect adjustment to retained earnings of $2.9 million. Of this amount, $1.0 million related to our continuing operations and $1.9 million related to our discontinued operations. We are exposed to credit losses primarily through sales of products and services. Our expected loss allowance methodology for accounts receivable is developed using historical collection experience, current and future economic and market conditions and a review of the current status of customers' trade accounts receivables. Due to the short-term nature of such receivables, the estimate of accounts receivable that may not be collected is based upon the aging of accounts receivable balances and the financial condition of customers. Additionally, specific allowance amounts are established to record the appropriate provision for customers that have a higher probability of default. Our monitoring activities include timely account reconciliation, dispute resolution, payment confirmation, consideration of customers' financial condition and macroeconomic conditions. Balances are written off when determined to be uncollectible. Estimates are used to determine the allowance, which is based upon an assessment of anticipated payments as well as other historical, current and future information that is reasonably available. The following table presents the activity in the allowance for doubtful accounts for our continuing operations for the year ended December 31, 2020 (in thousands). Balance at December 31, 2019 $ 2,569 Adoption adjustment 1,011 Current period provision 2,282 Recoveries collected (637) Write-offs (114) Currency impact 39 Balance at December 31, 2020 $ 5,150

Inventories

Inventories	12 Months Ended
	Dec. 31, 2020
Inventory Disclosure [Abstract]
Inventories	Inventories The major classes of inventories were as follows: December 31, 2020 2019 (In thousands) Raw materials $ 106,514 $ 98,530 Work-in-process 32,011 34,717 Finished goods 141,042 119,331 Gross inventories 279,567 252,578 Excess and obsolete reserves (32,269) (21,245) Net inventories $ 247,298 $ 231,333

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 The carrying values of property, plant and equipment were as follows: December 31, 2020 2019 (In thousands) Land and land improvements $ 29,321 $ 27,502 Buildings and leasehold improvements 136,427 126,580 Machinery and equipment 608,618 558,639 Computer equipment and software 137,512 119,533 Construction in process 63,589 70,993 Gross property, plant and equipment 975,467 903,247 Accumulated depreciation (606,847) (557,329) Net property, plant and equipment $ 368,620 $ 345,918 Depreciation Expense We recognized depreciation expense in income from continuing operations of $42.5 million, $40.4 million, and $38.3 million in 2020, 2019, and 2018, respectively.

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	Leases We have operating and finance leases for properties, including manufacturing facilities, warehouses, and office space; as well as vehicles and certain equipment. We make certain judgments in determining whether a contract contains a lease in accordance with ASU 2016-02. Our leases have remaining lease terms of less than 1 year to 15 years, some of which include options to extend the lease for a period of up to 15 years and some include options to terminate the leases within 1 year. We do not assume renewals in our determination of the lease term unless the renewals are deemed to be reasonably certain as of the commencement date of the lease. Our lease agreements do not contain any material residual value guarantees or material variable lease payments. We have entered into various short-term operating leases with an initial term of twelve months or less. These leases are not recorded on our balance sheet as of December 31, 2020 or 2019, and the rent expense for short-term leases was not material. We have certain property and equipment lease contracts that may contain lease and non-lease components, and we have elected to utilize the practical expedient to account for these components together as a single combined lease component. As the rate implicit in most of our leases is not readily determinable, we use the incremental borrowing rate to determine the present value of the lease payments, which is unique to each leased asset, and is based upon the term of the lease, commencement date of the lease, local currency of the leased asset, and the credit rating of the legal entity leasing the asset. The components of lease expense were as follows: Years Ended December 31, 2020 2019 (In thousands) Operating lease cost $ 14,348 $ 14,622 Finance lease cost Amortization of right-of-use asset $ 133 $ 142 Interest on lease liabilities 17 22 Total finance lease cost $ 150 $ 164 Supplemental cash flow information related to leases was as follows: Years Ended December 31, 2020 2019 (In thousands) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 15,489 $ 14,594 Operating cash flows from finance leases 16 25 Financing cash flows from finance leases 158 258 Supplemental balance sheet information related to leases was as follows: December 31, 2020 2019 (In thousands, except lease term and discount rate) Operating leases: Total operating lease right-of-use assets $ 54,787 $ 62,251 Accrued liabilities $ 14,742 $ 13,900 Long-term operating lease liabilities 46,398 55,652 Total operating lease liabilities $ 61,140 $ 69,552 Finance leases: Other long-lived assets, at cost $ 764 $ 823 Accumulated depreciation (483) (391) Other long-lived assets, net $ 281 $ 432 Weighted Average Remaining Lease Term Operating leases 5 years 6 years Finance leases 3 years 3 years Weighted Average Discount Rate Operating leases 6.6% 6.9 % Finance leases 4.9% 6.2 % The following table summarizes maturities of lease liabilities as of December 31, 2020 (in thousands): 2021 $ 19,250 2022 16,305 2023 12,552 2024 9,516 2025 8,718 Thereafter 8,901 Total $ 75,242 The following table summarizes maturities of lease liabilities as of December 31, 2019 (in thousands): 2020 $ 19,086 2021 16,988 2022 14,128 2023 11,598 2024 9,032 Thereafter 16,655 Total $ 87,487
Leases	Leases We have operating and finance leases for properties, including manufacturing facilities, warehouses, and office space; as well as vehicles and certain equipment. We make certain judgments in determining whether a contract contains a lease in accordance with ASU 2016-02. Our leases have remaining lease terms of less than 1 year to 15 years, some of which include options to extend the lease for a period of up to 15 years and some include options to terminate the leases within 1 year. We do not assume renewals in our determination of the lease term unless the renewals are deemed to be reasonably certain as of the commencement date of the lease. Our lease agreements do not contain any material residual value guarantees or material variable lease payments. We have entered into various short-term operating leases with an initial term of twelve months or less. These leases are not recorded on our balance sheet as of December 31, 2020 or 2019, and the rent expense for short-term leases was not material. We have certain property and equipment lease contracts that may contain lease and non-lease components, and we have elected to utilize the practical expedient to account for these components together as a single combined lease component. As the rate implicit in most of our leases is not readily determinable, we use the incremental borrowing rate to determine the present value of the lease payments, which is unique to each leased asset, and is based upon the term of the lease, commencement date of the lease, local currency of the leased asset, and the credit rating of the legal entity leasing the asset. The components of lease expense were as follows: Years Ended December 31, 2020 2019 (In thousands) Operating lease cost $ 14,348 $ 14,622 Finance lease cost Amortization of right-of-use asset $ 133 $ 142 Interest on lease liabilities 17 22 Total finance lease cost $ 150 $ 164 Supplemental cash flow information related to leases was as follows: Years Ended December 31, 2020 2019 (In thousands) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 15,489 $ 14,594 Operating cash flows from finance leases 16 25 Financing cash flows from finance leases 158 258 Supplemental balance sheet information related to leases was as follows: December 31, 2020 2019 (In thousands, except lease term and discount rate) Operating leases: Total operating lease right-of-use assets $ 54,787 $ 62,251 Accrued liabilities $ 14,742 $ 13,900 Long-term operating lease liabilities 46,398 55,652 Total operating lease liabilities $ 61,140 $ 69,552 Finance leases: Other long-lived assets, at cost $ 764 $ 823 Accumulated depreciation (483) (391) Other long-lived assets, net $ 281 $ 432 Weighted Average Remaining Lease Term Operating leases 5 years 6 years Finance leases 3 years 3 years Weighted Average Discount Rate Operating leases 6.6% 6.9 % Finance leases 4.9% 6.2 % The following table summarizes maturities of lease liabilities as of December 31, 2020 (in thousands): 2021 $ 19,250 2022 16,305 2023 12,552 2024 9,516 2025 8,718 Thereafter 8,901 Total $ 75,242 The following table summarizes maturities of lease liabilities as of December 31, 2019 (in thousands): 2020 $ 19,086 2021 16,988 2022 14,128 2023 11,598 2024 9,032 Thereafter 16,655 Total $ 87,487

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible Assets The carrying values of intangible assets were as follows: December 31, 2020 December 31, 2019 Gross Accumulated Net Gross Accumulated Net (In thousands) (In thousands) Goodwill $ 1,251,938 $ — $ 1,251,938 $ 1,243,669 $ — $ 1,243,669 Definite-lived intangible assets subject to amortization: Developed technology $ 428,187 $ (369,849) $ 58,338 $ 413,310 $ (331,696) $ 81,614 Customer relationships 295,382 (128,796) 166,586 297,595 (110,732) 186,863 Trademarks 65,861 (36,539) 29,322 56,393 (30,213) 26,180 In-service research and development 11,536 (9,774) 1,762 10,702 (7,160) 3,542 Backlog 11,421 (11,421) — 11,335 (10,935) 400 Total intangible assets subject to amortization 812,387 (556,379) 256,008 789,335 (490,736) 298,599 Indefinite-lived intangible assets not subject to amortization: Trademarks 31,063 — 31,063 40,106 — 40,106 In-process research and development — — — 800 — 800 Total intangible assets not subject to amortization 31,063 — 31,063 40,906 — 40,906 Intangible assets $ 843,450 $ (556,379) $ 287,071 $ 830,241 $ (490,736) $ 339,505 Segment Allocation of Goodwill and Trademarks The changes in the carrying amount of goodwill assigned to reporting units in our reportable segments are as follows: Enterprise Solutions Industrial Solutions Consolidated (In thousands) Balance at December 31, 2018 $ 432,082 $ 774,795 $ 1,206,877 Acquisitions and purchase accounting adjustments 38,209 — 38,209 Translation impact (260) (1,157) (1,417) Balance at December 31, 2019 $ 470,031 $ 773,638 $ 1,243,669 Acquisitions and purchase accounting adjustments 2,420 — 2,420 Translation impact 2,296 3,553 5,849 Balance at December 31, 2020 $ 474,747 $ 777,191 $ 1,251,938 The changes in the carrying amount of indefinite-lived trademarks are as follows: Enterprise Solutions Industrial Solutions Consolidated (In thousands) Balance at December 31, 2018 $ 27,000 $ 13,270 $ 40,270 Translation impact — (164) (164) Balance at December 31, 2019 $ 27,000 $ 13,106 $ 40,106 Reclassify to definite-lived — (9,043) (9,043) Balance at December 31, 2020 $ 27,000 $ 4,063 $ 31,063 Annual Impairment Test The annual measurement date for our goodwill and indefinite-lived intangible assets impairment test is our fiscal November month-end. For our 2020 goodwill impairment test, we performed a quantitative assessment for all ten of our reporting units and determined the estimated fair values of our reporting units by calculating the present values of their estimated future cash flows using Level 3 inputs. We did not perform a qualitative assessment over our reporting units. We determined that the fair values of the reporting units were in excess of the carrying values; therefore, we did not record any goodwill impairment for the ten reporting units. We also did not recognize any goodwill impairment from continuing operations in 2019 or 2018 based upon the results of our annual goodwill impairment testing. For our annual impairment test in 2020, the excess of the fair values over the carrying values of our ten reporting units tested under a quantitative income approach ranged from 4% - 345%. The assumptions used to estimate fair values were based on the past performance of the reporting unit as well as the projections incorporated in our strategic plan. Significant assumptions included sales growth, profitability, and related cash flows, along with cash flows associated with taxes and capital spending. The discount rate used to estimate fair value was risk adjusted in consideration of the economic conditions in effect at the time of the impairment test. We also considered assumptions that market participants may use. In our quantitative assessments, the discount rates ranged from 10.0% to 12.2%, the 2021 to 2030 compounded annual revenue growth rates ranged from 2.5% to 5.8%, and the revenue growth rates beyond 2030 ranged from 2.0% to 3.0%. By their nature, these assumptions involve risks and uncertainties. Furthermore, uncertainties associated with current market conditions increase the inherent risk associated with using an income approach to estimate fair values. While we have adjusted our key assumptions to reflect the current economic conditions, we have also assumed that economic conditions will improve. If current conditions persist and actual results are different from our estimates or assumptions, we may have to recognize an impairment charge that could be material. We test our indefinite-lived intangible assets, which consist pri marily of trademarks, for impairment on an annual basis during the fourth quarter. The accounting guidance related to impairment testing for such intangible assets allows for the performance of an optional qualitative assessment, similar to that described above for goodwill. We did not perform any qualitative assessments as part of our indefinite-lived intangible asset impairment testing for 2020. Rather, we performed a quantitative assessment for each of our indefinite-lived trademarks in 2020. Under the quantitative assessments, we determined the fair value of each trademark using a relief from royalty methodology and compared the fair value to the carrying value. Significant assumptions to determine fair value included sales growth, royalty rates, and discount rates. We did not recognize any trademark impairment charges from continuing operations in 2020, 2019, or 2018. Disposal Group Impairment During the fourth quarter of 2019, we committed to a plan to sell Grass Valley, and at such time, met all of the criteria to classify the assets and liabilities of this business as held for sale. Furthermore, we determined a divestiture of Grass Valley represents a strategic shift that is expected to have a major impact on our operations and financial results. As a result, the Grass Valley disposal group, previously included in our Enterprise Solutions segment, was reported within discontinued operations. We also ceased depreciating and amortizing the assets of the disposal group once they met the held for sale criteria in the fourth quarter of 2019. During 2019, we wrote down the carrying value of Grass Valley and recognized asset impairments totaling $521.4 million, which consisted of impairments to goodwill, customer relationships, and trademarks of $326.1 million, $14.4 million, and $1.6 million, respectively, as well as an impairment of the disposal group of $179.3 million ($180.4 million translated at year-end exchange rates). During 2020, we wrote down the carrying value of Grass Valley and recognized asset impairments totaling $113.0 million. We determined the estimated fair values of the assets and of the reporting unit by calculating the present values of their estimated future cash flows, which was based in part on the assumed proceeds from a divestiture of Grass Valley. Amortization Expense We recognized amortization expense in income from continuing operations of $66.2 million, $74.6 million, and $75.1 million in 2020, 2019, and 2018, respectively. We expect to recognize annual amortization expense of $35.6 million in 2021, $32.9 million in 2022, $31.2 million in 2023, $29.0 million in 2024, and $24.7 million in 2025 related to our intangible assets balance as of December 31, 2020. The weighted-average amortization period for our customer relationships, trademarks, developed technology, and in-service research and development is 18.2 years, 8.3 years, 6.8 years, and 5.0 years, respectively.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2020
Accrued Liabilities [Abstract]
Accrued Liabilities	Accrued Liabilities The carrying values of accrued liabilities were as follows: December 31, 2020 2019 (In thousands) Wages, severance and related taxes $ 65,892 $ 58,953 Current deferred revenue 53,371 54,255 Accrued rebates 32,192 37,170 Accrued interest 20,610 18,781 Employee benefits 27,707 17,791 Lease liabilities 14,840 14,072 Other (individual items less than 5% of total current liabilities) 62,029 82,777 Accrued liabilities $ 276,641 $ 283,799 At December 31, 2019, our other accrued liabilities balance included earnout consideration of $31.4 million in accordance with the purchase agreement for SAM, which was acquired on February 8, 2018 and included in the Grass Valley disposal group. During our fiscal first quarter of 2020, prior to the Grass Valley disposal, we paid the sellers of SAM the full earnout consideration . The acquisition-date fair value of the earnout liability was $29.3 million and is reflected as a financing activity in the Consolidated Cash Flow Statement with the remaining $2.1 million reflected as an operating activity.

Severance, Restructuring, and A

Severance, Restructuring, and Acquisition Integration Activities	12 Months Ended
	Dec. 31, 2020
Restructuring and Related Activities [Abstract]
Severance, Restructuring, and Acquisition Integration Activities	Severance, Restructuring, and Acquisition Integration Activities Cost Reduction Program During 2019, we began a cost reduction program to improve performance and enhance margins by streamlining the organizational structure and investing in technology to drive productivity. We recognized $4.0 million and $19.6 million of severance and other restructuring costs for this program during 2020 and 2019, respectively. These costs were incurred by both the Enterprise Solutions and Industrial Solutions segments. The cost reduction program is expected to deliver an estimated $60 million reduction in selling, general, and administrative expenses on an annual basis; approximately $40 million of which was realized in 2020, and the full benefit is expected to be materialized in 2021. We also expect to incur incremental costs of approximately $8 million for this program in 2021. FutureLink, Opterna, and SPC Integration Program In 2019, we began a restructuring program to integrate FutureLink, Opterna, and SPC with our existing businesses. The restructuring and integration activities were focused on achieving desired cost savings by consolidating existing and acquired facilities and other support functions. We recognized $4.9 million and $6.1 million of severance and other restructuring costs for this program during 2020 and 2019, respectively. These costs were incurred by the Enterprise Solutions segment. We expect to incur incremental costs of approximately $1 million for this program in 2021. Industrial Manufacturing Footprint Program In 2016, we began a program to consolidate our manufacturing footprint, which was later completed in 2018. We recognized severance and other restructuring costs of $17.7 million and $66.1 million for this program during 2018 and cumulatively, respectively. The costs were incurred by the Enterprise Solutions and Industrial Solutions segments, as the manufacturing locations involved in the program serve both platforms. The following table summarizes the costs by segment of the programs described above as well as other immaterial programs and acquisition integration activities: Severance Other Restructuring Total Costs (In thousands) Year Ended December 31, 2020 Enterprise Solutions $ 1,345 $ 6,374 $ 7,719 Industrial Solutions 1,706 2,833 4,539 Total $ 3,051 $ 9,207 $ 12,258 Year Ended December 31, 2019 Enterprise Solutions $ 5,018 $ 5,790 $ 10,808 Industrial Solutions 15,736 — 15,736 Total $ 20,754 $ 5,790 $ 26,544 Year Ended December 31, 2018 Enterprise Solutions $ 548 $ 14,315 $ 14,863 Industrial Solutions 240 7,522 7,762 Total $ 788 $ 21,837 $ 22,625 The other restructuring and integration costs primarily consisted of equipment transfers, costs to consolidate operating and support facilities, retention bonuses, relocation, travel, legal, and other costs. The majority of the other restructuring and integration costs related to these actions were paid as incurred or are payable within the next 60 days. The following table summarizes the costs of the various programs described above as well as other immaterial programs and acquisition integration activities by financial statement line item in the Consolidated Statement of Operations: Years ended December 31, 2020 2019 2018 (In thousands) Cost of sales $ 704 $ 3,425 $ 17,962 Selling, general and administrative expenses 11,554 23,119 4,546 Research and development expenses — — 117 Total $ 12,258 $ 26,544 $ 22,625 Accrued Severance The table below sets forth severance activity that occurred for the Cost Reduction Program and SPC, Opterna and FutureLink Integration Program described above. The balances below are included in accrued liabilities (in thousands). Balance at December 31, 2019 $ 19,575 New charges 2,529 Cash payments (4,483) Foreign currency translation (89) Other adjustments (4,147) Balance at March 29, 2020 $ 13,385 New charges 4,660 Cash payments (4,795) Foreign currency translation (132) Other adjustments (1,420) Balance at June 28, 2020 $ 11,698 New charges 2,060 Cash payments (3,968) Foreign currency translation (156) Other adjustments (1,541) Balance at September 27, 2020 $ 8,093 New charges 992 Cash payments (1,823) Foreign currency translation (95) Other adjustments (82) Balance at December 31, 2020 $ 7,085

Long-Term Debt and Other Borrow

Long-Term Debt and Other Borrowing Arrangements	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Long-Term Debt and Other Borrowing Arrangements	Long-Term Debt and Other Borrowing Arrangements The carrying values of our long-term debt and other borrowing arrangements were as follows: December 31, 2020 2019 (In thousands) Revolving credit agreement due 2022 $ — $ — Senior subordinated notes: 3.875% Senior subordinated notes due 2028 428,295 392,910 3.375% Senior subordinated notes due 2027 550,665 505,170 4.125% Senior subordinated notes due 2026 244,740 224,520 2.875% Senior subordinated notes due 2025 367,110 336,780 Total senior subordinated notes 1,590,810 1,459,380 Less unamortized debt issuance costs (17,084) (19,896) Long-term debt $ 1,573,726 $ 1,439,484 Revolving Credit Agreement due 2022 In 2017, we entered into an Amended and Restated Credit Agreement (the Revolver) to amend and restate our prior Revolving Credit Agreement. The Revolver provides a $400.0 million multi-currency asset-based revolving credit facility. The borrowing base under the Revolver includes eligible accounts receivable; inventory; and property, plant and equipment of certain of our subsidiaries in the U.S., Canada, Germany, and the Netherlands. The maturity date of the Revolver is May 16, 2022. Interest on outstanding borrowings is variable, based upon LIBOR or other similar indices in foreign jurisdictions, plus a spread that ranges from 1.25%-1.75%, depending upon our leverage position. We pay a commitment fee on our available borrowing capacity of 0.25%. In the event we borrow more than 90% of our borrowing base, we are subject to a fixed charge coverage ratio covenant. We paid approximately $2.3 million of fees when we amended the Revolver, which are being amortized over the remaining term of the Revolver. Due to the initial uncertainties arising from the COVID-19 pandemic and out of an abundance of caution, in April 2020 we borrowed $190.0 million on our Revolver, which we fully repaid by December 31, 2020 as a result of improved and sufficient liquidity and cash flow. As of December 31, 2020, we had no borrowings outstanding on the Revolver, and our available borrowing capacity was $230.2 million. Senior Subordinated Notes In March 2018, we completed an offering for €350.0 million ($431.3 million at issuance) aggregate principal amount of 3.875% senior subordinated notes due 2028 (the 2028 Notes). The carrying value of the 2028 Notes as of December 31, 2020 is $428.3 million. The 2 028 Notes are guaranteed on a senior subordinated basis by our current and future domestic subsidiaries. The 2028 Notes rank equal in right of payment with our senior subordinated notes due 2027, 2026, and 2025 and with any future subordinated debt, and they are subordinated to all of our senior debt and the senior debt of our subsidiary guarantors, including our Revolver. Interest is payable semiannually on March 15 and September 15 of each year, which commenced on September 15, 2018. We paid approximately $7.5 million of fees associated with the issuance of the 2028 Notes, which are being amortized over the life of the 2028 Notes using the effective interest method. We used the net proceeds from this offering and cash on hand to repurchase the 2023 and 2024 Notes - see further discussion below. We have outstanding €450.0 million aggregate principal amount of 3.375% senior subordinated notes due 2027 (the 2027 Notes). The carrying value of the 2027 Notes as of December 31, 2020 is $550.7 million. The 2027 Notes are guaranteed on a senior subordinated basis by our current and future domestic subsidiaries. The 2027 Notes rank equal in right of payment with our senior subordinated notes due 2028, 2026, and 2025 and with any future subordinated debt, and they are subordinated to all of our senior debt and the senior debt of our subsidiary guarantors, including our Revolver. Interest is payable semiannually on January 15 and July 15 of each year. We have outstanding €200.0 million aggregate principal amount of 4.125% senior subordinated notes due 2026 (the 2026 Notes). The carrying value of the 2026 Notes as of December 31, 2020 is $244.7 million. The 2026 Notes are guaranteed on a senior subordinated basis by our current and future domestic subsidiaries. The notes rank equal in right of payment with our senior subordinated notes due 2028, 2027, and 2025 and with any future subordinated debt, and they are subordinated to all of our senior debt and the senior debt of our subsidiary guarantors, including our Revolver. Interest is payable semiannually on April 15 and October 15 of each year. We have outstanding €300.0 million aggregate principal amount of 2.875% senior subordinated notes due 2025 (the 2025 Notes). The carrying value of the 2025 Notes as of December 31, 2020 is $367.1 million. The 2025 Notes are guaranteed on a senior subordinated basis by our current and future domestic subsidiaries. The 2025 Notes rank equal in right of payment with our senior subordinated notes due 2028, 2027, and 2026 and with any future subordinated debt, and they are subordinated to all of our senior debt and the senior debt of our subsidiary guarantors, including our Revolver. Interest is payable semiannually on March 15 and September 15 of each year. We had outstanding $200 million aggregate principal amount of 5.25% senior subordinated notes due 2024 (the 2024 Notes). In March 2018, we repurchased $188.7 million of the 2024 Notes outstanding for cash consideration of $199.8 million, including a prepayment penalty and recognized a $13.8 million loss on debt extinguishment including the write-off of unamortized debt issuance costs. In April 2018, we repurchased the remaining 2024 Notes outstanding for cash consideration of $11.9 million, including a prepayment penalty, and recognized a $0.8 million loss on debt extinguishment including the write-off of unamortized debt issuance costs. We had outstanding €200.0 million aggregate principal amount of 5.5% senior subordinated notes due 2023 (the 2023 Notes). In March 2018, we repurchased €143.1 million of the €200.0 million 2023 Notes outstanding for cash consideration of €147.8 million ($182.1 million), including a prepayment penalty and recognized a $6.2 million loss on debt extinguishment including the write-off of unamortized debt issuance costs. In April 2018, we repurchased the remaining 2023 Notes outstanding for cash consideration of €58.5 million ($71.6 million), including a prepayment penalty, and recognized a $2.2 million loss on debt extinguishment including the write-off of unamortized debt issuance costs. The senior subordinated notes due 2025, 2026, 2027 and 2028 are redeemable after September 15, 2020, October 15, 2021, July 15, 2022, and March 15, 2023, respectively, at the following redemption prices as a percentage of the face amount of the notes: Senior Subordinated Notes due 2025 2026 2027 2028 Year Percentage Year Percentage Year Percentage Year Percentage 2020 101.438 % 2021 102.063 % 2022 101.688 % 2023 101.938 % 2021 100.719 % 2022 101.375 % 2023 101.125 % 2024 101.292 % 2022 and thereafter 100.000 % 2023 100.688 % 2024 100.563 % 2025 100.646 % 2024 and thereafter 100.000 % 2025 and thereafter 100.000 % 2026 and thereafter 100.000 % Fair Value of Long-Term Debt The fair value of our senior subordinated notes as of December 31, 2020 was approximately $1,633.7 million based on quoted prices of the debt instruments in inactive markets (Level 2 valuation). This amount represents the fair values of our senior subordinated notes with a carrying value of $1,590.8 million as of December 31, 2020. Maturities Maturities on outstanding long-term debt and other borrowings during each of the five years subsequent to December 31, 2020 are as follows (in thousands): 2021 $ — 2022 — 2023 — 2024 — 2025 367,110 Thereafter 1,223,700 $ 1,590,810

Net Investment Hedge

Net Investment Hedge	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net Investment Hedge	Net Investment HedgeAll of our euro denominated notes were issued by Belden Inc., a USD functional currency entity. As of December 31, 2020, €767.8 million of our outstanding foreign denominated debt is designated as a net investment hedge on the foreign currency risk of our net investment in our euro foreign operations. The objective of the hedge is to protect the net investment in the foreign operation against adverse changes in the euro exchange rate. The transaction gain or loss is reported in the translation adjustment section of other comprehensive income. For the years ended December 31, 2020, 2019 and 2018, the transaction gain/(loss) associated with the net investment hedge reported in other comprehensive income was $(56.2) million, $26.6 million and $87.5 million, respectively. During 2020, we de-designated €532.2 million of our outstanding debt that was previously designated as a net investment hedge. After the de-designation, transaction gains or losses associated with this €532.2 million of debt are reported in income from continuing operations.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Years ended December 31, 2020 2019 2018 (in thousands) Income (loss) before taxes: United States operations $ (117,819) $ 42,833 $ 115,500 Foreign operations 183,946 109,577 114,580 Income before taxes $ 66,127 $ 152,410 $ 230,080 Income tax expense (benefit): Currently payable United States federal $ 273 $ 21,893 $ 31,730 United States state and local 91 3,090 3,912 Foreign 11,511 13,859 16,968 11,875 38,842 52,610 Deferred United States federal (1,754) 7,567 7,220 United States state and local (2,310) (1,205) (31) Foreign 3,913 (2,685) 3,137 (151) 3,677 10,326 Income tax expense $ 11,724 $ 42,519 $ 62,936 In addition to the above income tax expense associated with continuing operations, we also recorded an income tax benefit associated with discontinued operations of $22.6 million, $27.2 million, an d $3.3 million in 2020, 2019, and 2018, respectively. Years Ended December 31, 2020 2019 2018 Effective income tax rate reconciliation from continuing operations: United States federal statutory rate 21.0% 21.0% 21.0% State and local income taxes (2.6)% 1.2% 1.5% Impact of change in tax contingencies 2.3% —% (0.7)% Foreign income tax rate differences (38.2)% (8.6)% (1.0)% Impact of change in deferred tax asset valuation allowance 3.1% 9.2% 0.3% Domestic permanent differences and tax credits 33.9% 5.1% 1.9% Impact of tax reform —% —% 4.4% Impact of CARES act (1.8)% —% —% 17.7% 27.9% 27.4% In 2020, the most significant difference between the U.S. federal statutory tax rate and our effective tax rate was the impact of foreign tax rate differences. Foreign tax rate differences resulted in an income tax benefit of $25.3 million, $13.1 million, and $2.4 million in 2020, 2019, and 2018, respectively. Additionally, in 2020, 2019 and 2018, our income tax expense was reduced by $4.0 million, $3.9 million, and $3.0 million, respectively, due to a tax holiday for our operations in St. Kitts. The tax holiday in St. Kitts is scheduled to expire in 2022. An additional significant difference between the U.S. federal statutory tax rate and our effective tax rate was the impact of domestic permanent differences and tax credits. We recognized a total income tax expense from domestic permanent differences and tax credits of $22.4 million in 2020, primarily associated with our foreign income inclusions. In March 2020, the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) was signed into law in the United States. The Company generated a loss in the U.S. which will be carried back to prior years, as permitted by the CARES Act. The net impact to the tax provision as a result of the net operating loss carry back was a benefit of $1.2 million, primarily associated with the re-rate of the net operating loss carry back period. If we were to repatriate foreign cash to the U.S., we may be required to accrue and pay U.S. taxes in accordance with applicable U.S. tax rules and regulations as a result of the repatriation. However, it is our intent to permanently reinvest the earnings of our non-U.S. subsidiaries in those operations and for continued non-U.S. growth opportunities. As a result, as of December 31, 2020, we have not made a provision for U.S. or additional foreign withholding taxes. December 31, 2020 2019 (In thousands) Components of deferred income tax balances: Deferred income tax liabilities: Plant, equipment, and intangibles $ (92,271) $ (96,254) Right of use asset (17,610) (16,906) (109,881) (113,160) Deferred income tax assets: Postretirement, pensions, and stock compensation 35,394 28,169 Reserves and accruals 24,388 15,395 Net operating loss, capital loss, and tax credit carryforwards 107,028 76,456 Lease liability 18,515 17,882 Valuation allowances (84,308) (48,251) 101,017 89,651 Net deferred income tax liability $ (8,864) $ (23,509) On July 2, 2020, we completed the divestiture of Grass Valley to Black Dragon Capital. The increase in pensions and reserves is primarily due to the divestiture of Grass Valley. We derived $23.8 million of deferred tax assets in relation to a capital loss in the U.S. for the divestiture of Grass Valley. The increase in deferred tax valuation allowances is primarily due to the valuation allowance against the capital loss of $23.8 million that we do not expect to be able to realize prior to expiration and the valuation allowance against the seller’s note allowance. As of December 31, 2020, we had $205.4 million of gross net operating loss carryforwards and $57.1 million of tax credit carryforwards. Unless otherwise utilized, net operating loss carryforwards will expire upon the filing of the tax returns for the following respective years: $0.9 million in 2020, $19.7 million between 2021 and 2024, and $126.8 million between 2025 and 2040. Net operating loss with an indefinite carryforward period total $58.0 million. Of the $205.4 million in net operating loss carryforwards, we have determined, based on the weight of all available evidence, both positive and negative, that we will utilize $137.1 million of these net operating loss carryforwards within their respective expiration periods. A valuation allowance has been recorded on the remaining portion of the net operating loss carryforwards. Unless otherwise utilized, tax credit carryforwards of $57.1 million will expire as follows: $2.1 million between 2020 and 2024 and $49.6 million between 2025 and 2040. Tax credit carryforwards with an indefinite carryforward period total $5.4 million. We have determined, based on the weight of all available evidence, both positive and negative, that we will utilize $17.3 million of these tax credit carryforwards within their respective expiration periods. A valuation allowance has been recorded on the remaining portion of the tax credit carryforwards. As of December 31, 2020, we had $100.5 million of gross capital loss carryforwards in the U.S. with a full valuation allowance as we do not expect to be able to utilize the capital loss prior to expiration. The following tables summarize our net operating losses carryforwards and tax credit carryforwards as of December 31, 2020 by jurisdiction: Net Operating Loss Carryforwards (In thousands) Australia $ 10,546 Germany 15,852 Japan 653 Luxembourg 163 Netherlands 6,578 Other 20,723 United Kingdom 10,720 United States - Federal and various states 140,117 Total $ 205,352 Tax Credit Carryforwards (In thousands) United States $ 56,617 Canada 492 Total $ 57,109 In 2020, we recognized a net $1.8 million increase to reserves for uncertain tax positions. A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows: 2020 2019 (In thousands) Balance at beginning of year $ 6,779 $ 6,591 Additions based on tax positions related to the current year 548 488 Additions for tax positions of prior years 1,574 — Reductions for tax positions of prior years - Settlement (328) (300) Balance at end of year $ 8,573 $ 6,779 The balance of $8.6 million at December 31, 2020, reflects tax positions that, if recognized, would impact our effective tax rate. As of December 31, 2020, we believe it is reasonably possible that $1.7 million of unrecognized tax benefits will change within the next twelve months primarily attributable to the expected completion of tax audits in foreign jurisdictions. Our practice is to recognize interest and penalties related to uncertain tax positions in interest expense and operating expenses, respectively. We have approximately $0.2 million and $0.0 million accrued for the payment of interest and penalties as of December 31, 2020 and 2019, respectively. Our federal tax return for the tax years 2017 and later remain subject to examination by the Internal Revenue Service. Our state and foreign income tax returns for the tax years 2012 and later remain subject to examination by various state and foreign tax authorities.

Pension and Other Postretiremen

Pension and Other Postretirement Benefits	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Pension and Other Postretirement Benefits	Pension and Other Postretirement Benefits We sponsor defined benefit pension plans and defined contribution plans that cover substantially all employees in Canada, the Netherlands, the United Kingdom, the U.S., and certain employees in Germany. Certain defined benefit plans in the United Kingdom are frozen and additional benefits are not being earned by the participants. The U.S. defined benefit pension plan is closed to new entrants. Annual contributions to retirement plans equal or exceed the minimum funding requirements of applicable local regulations. The assets of the funded pension plans we sponsor are maintained in various trusts and are invested primarily in equity and fixed income securities. Benefits provided to employees under defined contribution plans include cash contributions by the Company based on either hours worked by the employee or a percentage of the employee’s compensation. Defined contribution expense for 2020, 2019, and 2018 was $10.0 million, $12.1 million, and $11.8 million, respectively. We sponsor unfunded postretirement medical and life insurance benefit plans for certain of our employees in Canada and the U.S. The medical benefit portion of the U.S. plan is only for employees who retired prior to 1989 as well as certain other employees who were near retirement and elected to receive certain benefits. The following tables provide a reconciliation of the changes in the plans’ benefit obligations and fair value of assets as well as a statement of the funded status and balance sheet reporting for these plans. Pension Benefits Other Benefits Years Ended December 31, 2020 2019 2020 2019 (In thousands) Change in benefit obligation: Benefit obligation, beginning of year $ (461,352) $ (412,880) $ (29,470) $ (26,143) Service cost (3,930) (3,668) (33) (35) Interest cost (9,729) (12,261) (809) (960) Participant contributions (73) (86) (5) (4) Actuarial loss (42,284) (39,329) (110) (2,374) Divestitures and acquisitions (910) — — — Settlements 26,970 49 — — Curtailments 236 — Plan amendments (226) — — — Foreign currency exchange rate changes (15,345) (9,890) (427) (1,260) Benefits paid 13,718 16,713 1,356 1,306 Benefit obligation, end of year $ (492,925) $ (461,352) $ (29,498) $ (29,470) Pension Benefits Other Benefits Years Ended December 31, 2020 2019 2020 2019 (In thousands) Change in plan assets: Fair value of plan assets, beginning of year $ 355,726 $ 311,509 $ — $ — Actual return on plan assets 32,470 45,896 — — Employer contributions 6,393 5,673 1,351 1,302 Plan participant contributions 73 86 5 4 Settlements (26,945) — — — Foreign currency exchange rate changes 7,803 9,275 — — Benefits paid (13,718) (16,713) (1,356) (1,306) Fair value of plan assets, end of year $ 361,802 $ 355,726 $ — $ — Funded status, end of year $ (131,123) $ (105,626) $ (29,498) $ (29,470) Amounts recognized in the balance sheets: Prepaid benefit cost $ 4,780 $ 5,542 $ — $ — Accrued benefit liability, current (3,558) (3,000) (1,443) (1,411) Accrued benefit liability, noncurrent (132,345) (108,168) (28,055) (28,059) Net funded status $ (131,123) $ (105,626) $ (29,498) $ (29,470) The accumulated benefit obligation for all defined benefit pension plans was $518.4 million and $456.9 million at December 31, 2020 and 2019, respectively. The projected benefit obligation, accumulated benefit obligation, and fair value of plan assets for the pension plans with a projected benefit obligation in excess of plan assets were $463.2 million, $459.2 million, and $297.8 million, respectively, as of December 31, 2020 and were $404.9 million, $400.4 million, and $293.7 million, respectively, as of December 31, 2019. The accumulated benefit obligation and fair value of plan assets for other postretirement benefit plans with an accumulated benefit obligation in excess of plan assets were $59.2 million and $64.0 million, respectively, as of December 31, 2020 and were $29.5 million and $0 million, respectively, as of December 31, 2019. The following table provides the components of net periodic benefit costs for the plans. Pension Benefits Other Benefits Years Ended December 31, 2020 2019 2018 2020 2019 2018 (In thousands) Components of net periodic benefit cost: Service cost $ 3,930 $ 3,668 $ 4,579 $ 33 $ 35 $ 47 Interest cost 9,729 12,261 11,480 809 960 945 Expected return on plan assets (16,357) (15,699) (16,389) — — — Amortization of prior service cost (credit) 190 169 (42) — — — Settlement loss (gain) 3,153 (7) 1,342 — — — Net loss (gain) recognition 2,930 1,432 2,775 (59) (133) (12) Net periodic benefit cost $ 3,575 $ 1,824 $ 3,745 $ 783 $ 862 $ 980 We recorded settlement losses totaling $3.2 million during 2020 and $1.3 million during 2018. The settlement losses were the result of lump-sum payments to participants that exceeded the sum of the pension plan's respective annual service cost and interest cost amounts. The following table presents the assumptions used in determining the benefit obligations and the net periodic benefit cost amounts. Pension Benefits Other Benefits Years Ended December 31, Years Ended December 31, 2020 2019 2020 2019 Weighted average assumptions for benefit obligations at year end: Discount rate 1.5 % 2.2 % 2.5 % 2.9 % Salary increase 3.3 % 3.5 % N/A N/A Cash balance interest credit rate 4.6 % 4.0 % N/A N/A Weighted average assumptions for net periodic cost for the year: Discount rate 2.2 % 3.1 % 2.9 % 3.7 % Salary increase 3.5 % 3.6 % N/A N/A Cash balance interest credit rate 4.0 % 4.7 % N/A N/A Expected return on assets 4.9 % 5.0 % N/A N/A Assumed health care cost trend rates: Health care cost trend rate assumed for next year N/A N/A 5.5 % 5.6 % Rate that the cost trend rate gradually declines to N/A N/A 5.0 % 5.0 % Year that the rate reaches the rate it is assumed to remain at N/A N/A 2026 2023 Plan assets are invested using a total return investment approach whereby a mix of equity securities and fixed income securities are used to preserve asset values, diversify risk, and achieve our target investment return benchmark. Investment strategies and asset allocations are based on consideration of the plan liabilities, the plan’s funded status, and our financial condition. Investment performance and asset allocation are measured and monitored on an ongoing basis. Plan assets are managed in a balanced portfolio comprised of two major components: an asset growth portion and an asset protection portion. The expected role of asset growth investments is to maximize the long-term real growth of assets, while the role of asset protection investments is to generate current income, provide for more stable periodic returns, and provide some protection against a permanent loss of capital. Absent regulatory or statutory limitations, the target asset allocation for the investment of the assets for our ongoing pension plans is 30-50% in asset protection investments and 50-70% in asset growth investments and for our pension plans where the majority of the participants are in payment or terminated vested status is 50-90% in asset protection investments and 10-50% in asset growth investments. Asset growth investments include a diversified mix of U.S. and international equity, primarily invested through investment funds. Asset protection investments include government securities and investment grade corporate bonds, primarily invested through investment funds and group insurance contracts. We develop our expected long-term rate of return assumptions based on the historical rates of returns for securities and instruments of the type in which our plans invest. The expected long-term rate of return on plan assets reflects the average rate of earnings expected on the invested assets and future assets to be invested to provide for the benefits included in the projected benefit obligation. We use historic plan asset returns co mbined with current market conditions to estimate the rate of return. The expected rate of return on plan assets is a long-term assumption based on an analysis of historical and forward looking returns considering the plan’s actual and target asset mix. The following table presents the fair values of the pension plan assets by asset category. December 31, 2020 December 31, 2019 Fair Market Value at December 31, 2020 Quoted Prices Significant Investments Measured at NAV Fair Market Value at December 31, 2019 Quoted Prices Significant Investments Measured at NAV (In thousands) (In thousands) Asset Category: Equity securities(a) U.S. equities fund $ 86,059 $ 3,012 $ — $ 83,047 $ 131,563 $ 2,793 $ — $ 128,770 Non-U.S. equities fund 61,630 5,602 — 56,028 54,496 5,949 — 48,547 Debt securities(b) Government bond fund 98,418 — 772 97,646 74,219 — 745 73,474 Corporate bond fund 82,434 — 12,150 70,284 40,940 — 9,854 31,086 Fixed income fund(c) 7,320 — — 7,320 35,895 — 33,701 2,194 Other investments(d) 17,367 — — 17,367 9,462 — — 9,462 Cash & equivalents 8,574 3,230 — 5,344 9,151 167 — 8,984 Total $ 361,802 $ 11,844 $ 12,922 $ 337,036 $ 355,726 $ 8,909 $ 44,300 $ 302,517 (a) This category includes investments in actively managed and indexed investment funds that invest in a diversified pool of equity securities of companies located in the U.S., Canada, Western Europe and other developed countries throughout the world. The funds are valued using the net asset value method in which an average of the market prices for the underlying investments is used to value the fund. Equity securities held in separate accounts are valued based on observable quoted prices on active exchanges. Funds which are valued using the net asset value method are not included in the fair value hierarchy. (b) This category includes investments in investment funds that invest in U.S. treasuries; other national, state and local government bonds; and corporate bonds of highly rated companies from diversified industries. The funds are valued using the net asset value method in which an average of the market prices for the underlying investments is used to value the fund. Funds valued using the net asset value method are not included in the fair value hierarchy. (c) This category includes guaranteed insurance contracts and annuity policies. (d) This category includes investments in hedge funds that pursue multiple strategies in order to provide diversification and balance risk/return objectives, real estate funds, and private equity funds. Funds valued using the net asset method are not included in the fair value hierarchy. The plans do not invest in individual securities. All investments are through well diversified investment funds. As a result, there are no significant concentrations of risk within the plan assets. The following table reflects the benefits as of December 31, 2020 expected to be paid in each of the next five years and in the aggregate for the five years thereafter from our pension and other postretirement plans. Because our other postretirement plans are unfunded, the anticipated benefits with respect to these plans will come from our own assets. Because our pension plans are primarily funded plans, the anticipated benefits with respect to these plans will come primarily from the trusts established for these plans. Pension Other (In thousands) 2021 $ 19,497 $ 1,460 2022 19,044 1,457 2023 20,320 1,458 2024 21,247 1,463 2025 19,417 1,466 2026-2030 99,881 7,413 Total $ 199,406 $ 14,717 We anticipate c ontributing $11.4 million and $1.5 million to our pension and other postretirement plans, respectively, during 2021. The pre-tax amounts in accumulated other comprehensive loss that have not yet been recognized as components of net periodic benefit cost at December 31, 2020 and the changes in these amounts during the year ended December 31, 2020 are as follows. Pension Other (In thousands) Components of accumulated other comprehensive loss: Net actuarial loss (gain) $ 80,671 $ (436) Net prior service cost 2,798 — $ 83,469 $ (436) Pension Other (In thousands) Changes in accumulated other comprehensive loss: Net actuarial loss (gain), beginning of year $ 56,746 $ (600) Amortization of actuarial gain (loss) (2,930) 59 Actuarial loss 42,048 110 Asset gain (16,113) — Settlement loss recognized (3,153) — Divestitures and acquisitions 335 — Currency impact 3,738 (5) Net actuarial loss (gain), end of year $ 80,671 $ (436) Prior service cost, beginning of year $ 2,661 $ — Amortization of prior service cost (190) — Prior service cost occurring during the year 226 — Currency impact 101 — Prior service cost, end of year $ 2,798 $ —

Comprehensive Income and Accumu

Comprehensive Income and Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Comprehensive Income and Accumulated Other Comprehensive Income (Loss)	Comprehensive Income and Accumulated Other Comprehensive Income (Loss) The accumulated balances related to each component of other comprehensive income (loss), net of tax, are as follows: Foreign Currency Pension and Other Accumulated Other Comprehensive Income (Loss) (In thousands) Balance at December 31, 2018 $ (41,882) $ (33,025) $ (74,907) Other comprehensive gain (loss) attributable to Belden before reclassifications 23,657 (13,281) 10,376 Amounts reclassified from accumulated other comprehensive income — 1,113 1,113 Net current period other comprehensive gain (loss) attributable to Belden 23,657 (12,168) 11,489 Balance at December 31, 2019 $ (18,225) $ (45,193) $ (63,418) Other comprehensive loss attributable to Belden before reclassifications (123,101) (20,800) (143,901) Amounts reclassified from accumulated other comprehensive income 10,145 5,323 15,468 Net current period other comprehensive loss attributable to Belden (112,956) (15,477) (128,433) Balance at December 31, 2020 $ (131,181) $ (60,670) $ (191,851) The following table summarizes the effects of reclassifications from accumulated other comprehensive income (loss): Amount Reclassified from Affected Line Item in the (In thousands) Amortization of pension and other postretirement benefit plan items: Settlement loss $ 3,153 (1) Accumulated losses of Grass Valley disposal group 771 (2) Actuarial losses 2,871 (1) Prior service cost 190 (1) Total before tax 6,985 Tax benefit (1,662) Total net of tax $ 5,323 (1) The amortization of these accumulated other comprehensive income (loss) components are included in the computation of net periodic benefit costs (see Note 19). (2) In addition, we reclassified $10.1 million of accumulated foreign currency translation losses associated with the Grass Valley disposal group that are included in the calculation of the loss on disposal of discontinued operations.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation Compensation cost charged against income, primarily selling, general and administrative expense, and the income tax benefit recognized for our share-based compensation arrangements is included below: Years Ended December 31, 2020 2019 2018 (In thousands) Total share-based compensation cost $ 19,171 $ 16,802 $ 17,143 Income tax benefit 4,563 3,999 4,080 We currently have outstanding stock appreciation rights (SARs), restricted stock units with service vesting conditions, restricted stock units with performance vesting conditions, and restricted stock units with market conditions. We grant SARs with an exercise price equal to the closing market price of our common stock on the grant date. Generally, SARs may be converted into shares of our common stock in equal amounts on each of the first three anniversaries of the grant date and expire 10 years from the grant date. Certain awards provide for accelerated vesting in certain circumstances, including following a change in control of the Company. Restricted stock units with service conditions generally vest 3-5 years from the grant date. Restricted stock units issued based on the attainment of the performance conditions generally vest on the second or third anniversary of their grant date. Restricted stock units issued based on the attainment of market conditions generally vest on the third anniversary of their grant date. We recognize compensation cost for all awards based on their fair values. The fair values for SARs are estimated on the grant date using the Black-Scholes-Merton option-pricing formula which incorporates the assumptions noted in the following table. Expected volatility is based on historical volatility, and expected term is based on historical exercise patterns of SAR holders. The fair value of restricted stock units with service vesting conditions or performance vesting conditions is the closing market price of our common stock on the date of grant. We estimate the fair value of certain restricted stock units with market conditions using a Monte Carlo simulation valuation model with the assistance of a third party valuation firm. Compensation costs for awards with service conditions are amortized to expense using the straight-line method. Compensation costs for awards with performance conditions and graded vesting are amortized to expense using the graded attribution method. During the year ended December 31, 2020, certain restricted stock units with performance vesting conditions were modified as a result of approved changes to the performance targets. There were no other changes to the terms of the restricted stock units. The modification was applicable to all employees who were previously granted the affected restricted stock units. Prior to the modification, the performance targets were not expected to be achieved. Therefore, we had not recognized any expense for these restricted stock units on a cumulative basis. As of the modification date, we expect to recognize total incremental compensation expense as a result of the modification of $4.4 million, of which $1.4 million was recognized in 2020. The remaining expense will be recognized over the applicable service periods, which extend to 2023. Years Ended December 31, 2020 2019 2018 (In thousands, except weighted average fair Weighted-average fair value of SARs and options granted $ 18.29 $ 22.31 $ 25.19 Total intrinsic value of SARs converted and options exercised 545 354 2,263 Tax benefit (expense) related to share-based compensation (560) (101) 113 Weighted-average fair value of restricted stock shares and units granted 41.75 64.61 72.54 Total fair value of restricted stock shares and units vested 6,600 10,325 5,740 Expected volatility 37.55 % 35.05 % 33.16 % Expected term (in years) 5.7 5.7 5.6 Risk-free rate 1.44 % 2.56 % 2.70 % Dividend yield 0.39 % 0.32 % 0.27 % SARs and Stock Options Restricted Shares and Units Number Weighted- Weighted- Aggregate Number Weighted- (In thousands, except exercise prices, fair values, and contractual terms) Outstanding at January 1, 2020 1,367 $ 65.04 n/a n/a 737 $ 68.31 Granted 149 51.14 n/a n/a 565 41.75 Exercised or converted (38) 38.24 n/a n/a (102) 64.56 Forfeited or expired (167) 66.42 n/a n/a (247) 75.07 Outstanding at December 31, 2020 1,311 $ 64.06 5.7 $ (29,054) 953 $ 52.50 Vested or expected to vest at December 31, 2020 1,266 $ 64.09 5.7 $ (28,096) Exercisable or convertible at December 31, 2020 1,021 $ 62.62 5.5 $ (24,060) At December 31, 2020, the total unrecognized compensat ion cost related to all nonvested awards was $25.0 million. That cost is expected to be recognized over a weighted-average period of 1.6 years. Historically, we have issued treasury shares, if available, to satisfy award c onversions and exercises.

Preferred Stock

Preferred Stock	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Preferred Stock	Preferred StockIn 2016, we issued 5.2 million depositary shares, each of which represented 1/100th interest in a share of 6.75% Series B Mandatory Convertible Preferred Stock (the Preferred Stock), for an offering price of $100 per depositary share. We received approximately $501 million of net proceeds from this offering, which were used for general corporate purposes. On July 15, 2019, all outstanding Preferred Stock was automatically converted into shares of Belden common stock at the conversion rate of 132.50, resulting in the issuance of approximately 6.9 million shares of Belden common stock. Upon conversion, the Preferred Stock was automatically extinguished and discharged, is no longer deemed outstanding for all purposes, and delisted from trading on the New York Stock Exchange. For the years ended December 31, 2020, 2019, and 2018, dividends on the Preferred Stock were $0.0 million, $18.4 million, and $34.9 million, respectively.

Stockholder Rights Plan

Stockholder Rights Plan	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Stockholder Rights Plan	Stockholder Rights PlanOn March 27, 2018, our Board of Directors authorized the redemption of all outstanding preferred share purchase rights issued pursuant to the then existing Rights Agreement. Under the former Rights Agreement, one right was attached to each outstanding share of common stock. The rights were redeemed at a redemption price of $0.01 per right, resulting in a total payment of $0.4 million to the holders of the rights as of the close of business on March 27, 2018.

Share Repurchases

Share Repurchases	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Share Repurchases	Share Repurchases On May 25, 2017, our Board of Directors authorized a share repurchase program, which allowed us to purchase up to $200.0 million of our common stock through open market repurchases, negotiated transactions, or other means, in accordance with applicable securities laws and other restrictions. This program was funded with cash on hand and cash flows from operating activities. During 2018, we repurchased 2.7 million shares of our common stock under the program for an aggregate cost of $175.0 million and an average price per share of $64.94; exhausting the $200.0 million authorized under this share repurchase program. On November 29, 2018, our Board of Directors authorized another share repurchase program, which allows us to purchase up to $300.0 million of our common stock through open market repurchases, negotiated transactions, or other means, in accordance with applicable securities laws and other restrictions. During 2018, we did not repurchase any shares of our common stock under this program. During 2019, we repurchased 0.9 million shares of our common stock under the program for an aggregate cost of $50.0 million and an average price per share of $56.19. During 2020, we repurchased 1.0 million shares of our common stock under the share repurchase program for an aggregate cost of $35.0 million at an average price per share of $35.83.

Market Concentrations and Risks

Market Concentrations and Risks	12 Months Ended
	Dec. 31, 2020
Risks and Uncertainties [Abstract]
Market Concentrations and Risks	Market Concentrations and Risks Concentrations of Credit We sell our products to many customers in several markets across multiple geographic areas. The ten largest customers, of which six are distributors, constitute in aggregate approximately 40%, 39%, and 40% of revenues in 2020, 2019, and 2018, respectively. Unconditional Commodity Purchase Obligations At December 31, 2020, we were committed to purchase approximately 1.9 million pounds of copper at an aggregate fixed cost of $6.0 million. At December 31, 2020, this fixed cost was $0.7 million less than the market cost that would be incurred on a spot purchase of the same amount of copper. The aggregate market cost was based on the current market price of copper obtained from the New York Mercantile Exchange. Labor Approximately 28% of our labor force is covered by collective bargaining agreements at various locations around the world. Approximately 25% of our labor force is covered by collective bargaining agreements that we expect to renegotiate during 2021. Fair Value of Financial Instruments

Contingent Liabilities

Contingent Liabilities	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Contingent Liabilities	Contingent Liabilities General Various claims are asserted against us in the ordinary course of business including those pertaining to income tax examinations, product liability, customer, employment, vendor, and patent matters. Based on facts currently available, management believes that the disposition of the claims that are pending or asserted will not have a materially adverse effect on our financial position, operating results, or cash flow. Letters of Credit, Guarantees and Bonds At December 31, 2020, we were party to unused standby letters of credit, bank guarantees, and surety bonds totaling $8.5 million, $4.1 million, and $3.3 million, respectively. These commitments are generally issued to secure obligations we have for a variety of commercial reasons, such as workers compensation self-insurance programs in several states and the importation and exportation of product.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information Supplemental cash flow information is as follows: Years Ended December 31, 2020 2019 2018 (In thousands) Income tax refunds received $ 4,460 $ 4,695 $ 3,920 Income taxes paid (25,259) (40,760) (52,147) Interest paid (53,029) (51,160) (48,519)

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsOn January 29, 2021, we acquired privately held OTN Systems N.V., a leading provider of automation networking infrastructure solutions, for approximately $71 million, net of cash acquired. The acquisition was funded with cash on hand. Headquartered in Olen, Belgium, OTN Systems is a leading provider of easy to use and highly-reliable network solutions tailored for specific applications in harsh, mission-critical environments. OTN Systems’ value-added technology allows customers to easily build, maintain, and monitor complex networks in growing industrial markets, such as Process, Power Transmission, and Mass Transit.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2020
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	Schedule II – Valuation and Qualifying Accounts Beginning ASU 2016-13 Adoption Adjustment Charged to Divestitures/ Charge Recoveries Currency Ending (In thousands) Accounts Receivable — Allowance for Doubtful Accounts: 2020 $ 2,569 $ 1,011 $ 2,282 $ — $ (114) $ (637) $ 39 $ 5,150 2019 3,137 — 159 368 (969) (86) (40) 2,569 2018 3,709 — 353 — (567) (176) (182) 3,137 Inventories — Excess and Obsolete Allowances: 2020 $ 21,245 $ — $ 15,915 $ — $ (4,540) $ (597) $ 246 $ 32,269 2019 17,364 — 6,403 452 (2,333) (606) (35) 21,245 2018 19,887 — 2,801 — (2,464) (2,675) (185) 17,364 Deferred Income Tax Asset — Valuation Allowance: 2020 $ 48,251 $ — $ 3,142 $ 33,003 $ (303) $ (114) $ 329 $ 84,308 2019 37,235 — 12,356 330 — (1,629) (41) 48,251 2018 47,636 — 13,459 (2) (22,577) (928) (353) 37,235

Summary of Significant Accoun_2

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Business Description	Business Description Belden Inc. (the Company, us, we, or our) is a global supplier of specialty networking solutions built around two global business platforms – Enterprise Solutions and Industrial Solutions. Our comprehensive portfolio of solutions enables customers to transmit and secure data, sound, and video for mission critical applications across complex enterprise and industrial environments.
Consolidation	Consolidation The accompanying Consolidated Financial Statements include Belden Inc. and all of its subsidiaries, including variable interest entities for which we are the primary beneficiary. We eliminate all significant affiliate accounts and transactions in consolidation.
Foreign Currency	Foreign Currency For international operations with functional currencies other than the United States (U.S.) dollar, we translate assets and liabilities at current exchange rates; we translate income and expenses using average exchange rates. We report the resulting translation adjustments, as well as gains and losses from certain affiliate transactions, in accumulated other comprehensive income (loss), a separate component of stockholders’ equity. We include exchange gains and losses on transactions in operating income. We determine the functional currency of our foreign subsidiaries based upon the currency of the primary economic environment in which each subsidiary operates. Typically, that is determined by the currency in which the subsidiary primarily generates and expends cash. We have concluded that the local currency is the functional currency for all of our material subsidiaries.
Reporting Periods	Reporting Periods Our fiscal year and fiscal fourth quarter both end on December 31. Our fiscal first quarter ends on the Sunday falling closest to 91 days after December 31. Our fiscal second and third quarters each have 91 days.
Use of Estimates in the Preparation of the Financial Statements	Use of Estimates in the Preparation of the Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the U.S. requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, and operating results and the disclosure of contingencies. Actual results could differ from those estimates. We make significant estimates with respect to the collectability and valuation of receivables, the valuation of inventory, the realization of deferred tax assets, the valuation of goodwill and indefinite-lived intangible assets, the valuation of contingent liabilities, the calculation of share-based compensation, the calculation of pension and other postretirement benefits expense, and the valuation of acquired businesses.
Reclassifications	Reclassifications We have made certain reclassifications to the 2019 and 2018 Consolidated Financial Statements, primarily as a result of the West Penn Wire business and multi-conductor product line transfer from the Enterprise Solutions segment to the Industrial Solutions segment in 2020. See Note 6.
Fair Value Measurement	Fair Value Measurement Accounting guidance for fair value measurements specifies a hierarchy of valuation techniques based upon whether the inputs to those valuation techniques reflect assumptions other market participants would use based upon market data obtained from independent sources or reflect our own assumptions of market participant valuation. The hierarchy is broken down into three levels based on the reliability of the inputs as follows: • Level 1 – Quoted prices in active markets that are unadjusted and accessible at the measurement date for identical, unrestricted assets or liabilities; • Level 2 – Quoted prices for identical assets and liabilities in markets that are not active, quoted prices for similar assets and liabilities in active markets, or financial instruments for which significant inputs are observable, either directly or indirectly; and • Level 3 – Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable.
Cash and Cash Equivalents	Cash and Cash Equivalents We classify cash on hand and deposits in banks, including commercial paper, money market accounts, and other investments with an original maturity of three months or less, that we hold from time to time, as cash and cash equivalents. We periodically have cash equivalents consisting of short-term money market funds and other investments. As of December 31, 2020 and 2019, we did not have any such cash equivalents on hand. The primary objective of our investment activities is to preserve our capital for the purpose of funding operations. We do not enter into investments for trading or speculative purposes.
Accounts Receivable and Revenue Reserves	Accounts Receivable and Revenue Reserves We classify amounts owed to us and due within twelve months, arising from the sale of goods or services and from other business activities, as current receivables. We classify receivables due after twelve months as other long-lived assets. At the time of sale, we establish an estimated reserve for trade, promotion, and other special price reductions such as contract pricing, discounts to meet competitor pricing, and on-time payment discounts. We also adjust receivable balances for, among other things, correction of billing errors, incorrect shipments, and settlement of customer disputes. Customers are allowed to return inventory if and when certain conditions regarding the physical state of the inventory and our approval of the return are met. Certain distribution customers are allowed to return inventory at original cost, in an amount not to exceed three percent of the prior year’s purchases, in exchange for an order of equal or greater value. Until we can process these reductions, corrections, and returns (together, the Changes) through individual customer records, we estimate the amount of outstanding Changes and recognize them by reducing revenues. We base these estimates on historical and anticipated sales demand, trends in product pricing, and historical and anticipated Changes patterns. We make revisions to these estimates in the period in which the facts that give rise to each revision become known. Future market conditions might require us to take actions to further reduce prices and increase customer return authorizations. Unprocessed Changes recognized against our gross accounts receivable balance at December 31, 2020 and 2019 totale d $25.5 million and $29.5 million, respectively. Unprocessed Changes recognized as accrued liabilities at December 31, 2020 and 2019 totaled $13.0 million and $11.0 million, respectively.
Inventories and Related Reserves	Inventories and Related Reserves Inventories are stated at the lower of cost or net realizable value. We determine the cost of all raw materials, work-in-process, and finished goods inventories by the first in, first out method. Cost components of inventories include direct labor, applicable production overhead, and amounts paid to suppliers of materials and products as well as freight costs and, when applicable, duty costs to import the materials and products.
Property, Plant and Equipment	Property, Plant and Equipment We record property, plant and equipment at cost. We calculate depreciation on a straight-line basis over the estimated useful lives of the related assets ranging from 10 to 40 years for buildings, 5 to 12 years for machinery and equipment, and 5 to 10 years for computer equipment and software. Construction in process reflects amounts incurred for the configuration and build-out of property, plant and equipment and for property, plant and equipment not yet placed into service. We charge maintenance and repairs—both planned major activities and less-costly, ongoing activities—to expense as incurred. We capitalize interest costs associated with the construction of capital assets and amortize the costs over the assets’ useful lives. Depreciation expense is included in costs of sales; selling, general and administrative expenses; and research and development expenses in the Consolidated Statements of Operations based on the specific categorization and use of the underlying assets being depreciated. We review property, plant and equipment to determine whether an event or change in circumstances indicates the carrying values of the assets may not be recoverable. We base our evaluation on the nature of the assets, the future economic benefit of the assets, and any historical or future profitability measurements, as well as other external market conditions or factors that may be present. If such impairment indicators are present or other factors exist that indicate that the carrying amount of an asset may not be recoverable, we determine whether impairment has occurred through the use of an undiscounted cash flow analysis. If impairment has occurred, we recognize a loss for the difference between the carrying amount and the fair value of the asset. For purposes of impairment testing of long-lived assets, we have identified asset groups at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities. Generally, our asset groups are based on an individual plant or operating facility level. In some circumstances, however, a combination of plants or operating facilities may be considered the asset group due to interdependence of operational activities and cash flows.
Goodwill and Intangible Assets	Goodwill and Intangible Assets Our intangible assets consist of (a) definite-lived assets subject to amortization such as developed technology, customer relationships, certain in-service research and development, certain trademarks, backlog, and capitalized software intangible assets, and (b) indefinite-lived assets not subject to amortization such as goodwill, certain trademarks, and certain in-process research and development intangible assets. We record amortization of the definite-lived intangible assets over the estimated useful lives of the related assets, which generally range from one year or less for backlog to more than 25 years for certain of our customer relationships. We determine the amortization method for our definite-lived intangible assets based on the pattern in which the economic benefits of the intangible asset are consumed. In the event we cannot reliably determine that pattern, we utilize a straight-line amortization method. We test our goodwill and other indefinite-lived intangible assets not subject to amortization for impairment on an annual basis as of our fiscal November month-end or when indicators of impairment exist. We base our estimates on assumptions we believe to be reasonable, but which are not predictable with precision and therefore are inherently uncertain. Actual future results could differ from these estimates. The accounting guidance related to goodwill impairment testing allows for the performance of an optional qualitative assessment of whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. Such an evaluation is made based on the weight of all available evidence and the significance of all identified events and circumstances that may influence the fair value of a reporting unit. If it is more likely than not that the fair value is less than the carrying value, then a quantitative assessment is required for the reporting u nit, as described in the paragraph below. In 2020, we did not perform a qualitative assessment over any of our reporting units. For our annual impairment test in 2020, we performed a quantitative assessment for all ten of our reporting units included in continuing operations. Under a quantitative assessment for goodwill impairment, we determine the fair value using the income approach (using Level 3 inputs) as reconciled to our aggregate market capitalization. Under the income approach, we calculate the fair value of a reporting unit based on the present value of estimated future cash flows. If the fair value of the reporting unit exceeds the carrying value of the net assets including goodwill assigned to that unit, goodwill is not impaired. If the carrying value of the reporting unit’s net assets including goodwill exceeds the fair value of the reporting unit, then we record an impairment charge based on that difference. In addition to the income approach, we calculate the fair value of our reporting units under a market approach. The market approach measures the fair value of a reporting unit through analysis of financial multiples of comparable businesses. Consideration is given to the financial conditions and operating performance of the reporting unit being valued relative to those publicly-traded companies operating in the same or similar lines of business. Based on our annual goodwill impairment test, the excess of the fair values over the carrying values of our ten reporting units tested under a quantitative income approach ranged from 4% - 345%. As a result, the goodwill balances for our continuing operations reporting units were not impaired in 2020. Furthermore, we did not recognize any goodwill impairment from continuing operations in 2019 or 2018. See Note 13 for further discussion. We also evaluate indefinite lived intangible assets for impairment annually or at other times if events have occurred or circumstances exist that indicate the carrying values of those assets may no longer be recoverable. We compare the fair value of the asset with its carrying amount. If the carrying amount of the asset exceeds its fair value, we recognize an impairment loss in an amount equal to that excess. We did not recognize impairment charges for our indefinite lived intangible assets from continuing operations in 2020, 2019, or 2018. See Note 13 for further discussion. We review intangible assets subject to amortization whenever an event or change in circumstances indicates the carrying values of the assets may not be recoverable. We test intangible assets subject to amortization for impairment and estimate their fair values using the same assumptions and techniques we employ on property, plant and equipment. We did not recognize any impairment charges for amortizable intangible assets from continuing operations in 2020, 2019, or 2018. Due to its overall financial performance and discontinued operations classification, we performed impairment tests on the Grass Valley disposal group, which resulted in total asset impairments of $113.0 million and $521.4 million in 2020 and 2019, respectively. The 2019 impairment charge consisted of impairments to goodwill, customer relationships, and trademarks of $326.1 million, $14.4 million, and $1.6 million, respectively, as well as an impairment of the disposal group of $179.3 million ($180.4 million translated at year-end exchange rates). We determined the estimated fair values of the assets and of the reporting unit by calculating the present values of their estimated future cash flows.
Disposals	Disposals During 2020, we sold a previously closed operating facility for net proceeds of $2.1 million and recognized a $0.4 million gain on the sale as well as completed the sale of Grass Valley to Black Dragon Capital - See Note 5. During 2018, we sold a previously closed operating facility for net proceeds of $1.5 million and recognized a $0.6 million gain on the sale.
Pension and Other Postretirement Benefits	Pension and Other Postretirement Benefits Our pension and other postretirement benefit costs and obligations are dependent on the various actuarial assumptions used in calculating such amounts. These assumptions relate to discount rates, salary growth, long-term return on plan assets, health care cost trend rates, mortality tables, and other factors. We base the discount rate assumptions on current investment yields on high-quality corporate long-term bonds. The salary growth assumptions reflect our long-term actual experience and future or near-term outlook. We determine the long-term return on plan assets based on historical portfolio results and management’s expectation of the future economic environment. Our health care cost trend assumptions are developed based on historical cost data, the near-term outlook, and an assessment of likely long-term trends. Actual results that differ from our assumptions are accumulated and, if in excess of the lesser of 10% of the projected benefit obligation or the fair market value of plan assets, are amortized over the estimated future working life of the plan participants.
Revenue Recognition	Accrued Sales RebatesWe grant incentive rebates to participating customers as part of our sales programs. The rebates are determined based on certain targeted sales volumes. Rebates are paid quarterly or annually in either cash or receivables credits. Until we can process these rebates through individual customer records, we estimate the amount of outstanding rebates and recognize them as accrued liabilities and reductions in our gross revenues. We base our estimates on both historical and anticipated sales demand and rebate program participation. We charge revisions to these estimates back to accrued liabilities and revenues in the period in which the facts that give rise to each revision become known. Future market conditions and product transitions might require us to take actions to increase sales rebates offered, possibly resulting in an incremental increase in accrued liabilities and an incremental reduction in revenues at the time the rebate is offered. Revenue Recognition We recognize revenue consistent with the principles as outlined in the following five step model: (1) identify the contract with the customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when (or as) each performance obligation is satisfied. See Note 3.
Contingent Liabilities	Contingent Liabilities We have established liabilities for environmental and legal contingencies that are probable of occurrence and reasonably estimable, the amounts of which are currently not material. A significant amount of judgment and use of estimates is required to quantify our ultimate exposure in these matters. We review the valuation of these liabilities on a quarterly basis, and we adjust the balances to account for changes in circumstances for ongoing and emerging issues. We accrue environmental remediation costs based on estimates of known environmental remediation exposures developed in consultation with our environmental consultants and legal counsel, the amounts of which are not currently material. We expense environmental compliance costs, which include maintenance and operating costs with respect to ongoing monitoring programs, as incurred. We evaluate the range of potential costs to remediate environmental sites. The ultimate cost of site clean-up is difficult to predict given the uncertainties of our involvement in certain sites, uncertainties regarding the extent of the required clean-up, the availability of alternative clean-up methods, variations in the interpretation of applicable laws and regulations, the possibility of insurance recoveries with respect to certain sites, and other factors. We are, from time to time, subject to routine litigation incidental to our business. These lawsuits primarily involve claims for damages arising out of the use of our products, allegations of patent or trademark infringement, and litigation and administrative proceedings involving employment matters and commercial disputes. Assessments regarding the ultimate cost of lawsuits require judgments concerning matters such as the anticipated outcome of negotiations, the number and cost of pending and future claims, and the impact of evidentiary requirements. Based on facts currently available, we believe the disposition of the claims that are pending or asserted will not have a materially adverse effect on our financial position, results of operations or cash flow.
Business Combination Accounting	Business Combination Accounting We allocate the consideration of an acquired business to its identifiable assets and liabilities based on estimated fair values. The excess of the consideration over the amount allocated to the assets and liabilities, if any, is recorded to goodwill. We use all available information to estimate fair values. We typically engage third party valuation specialists to assist in the fair value determination of inventories, tangible long-lived assets, and intangible assets other than goodwill. The carrying values of acquired receivables and accounts payable have historically approximated their fair values as of the business combination date. As necessary, we may engage third party specialists to assist in the estimation of fair value for certain liabilities, such as deferred revenue or postretirement benefit liabilities. We adjust the preliminary acquisition accounting, as necessary, typically up to one year after the acquisition closing date as we obtain more information regarding asset valuations and liabilities assumed.
Cost of Sales	Cost of Sales Cost of sales includes our total cost of inventory sold during the period, including material, labor, production overhead costs, variable manufacturing costs, and fixed manufacturing costs. Production overhead costs include operating supplies, applicable utility expenses, maintenance costs, and scrap. Variable manufacturing costs include inbound, interplant, and outbound freight, inventory shrinkage, and charges for excess and obsolete inventory. Fixed manufacturing costs include the costs associated with our purchasing, receiving, inspection, warehousing, distribution centers, production and inventory control, and manufacturing management. Cost of sales also includes the costs to provide maintenance and support and other professional services.
Shipping and Handling Costs	Shipping and Handling Costs We recognize fees earned on the shipment of product to customers as revenues and recognize costs incurred on the shipment of product to customers as a cost of sales.
Selling, General and Administrative Expenses	Selling, General and Administrative Expenses Selling, general and administrative expenses include expenses not directly related to the production of inventory. They include all expenses related to selling and marketing our products, as well as the salary and benefit costs of associates performing the selling and marketing functions. Selling, general and administrative expenses also include salary and benefit costs, purchased services, and other costs related to our executive and administrative functions.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred.
Advertising Costs	Advertising CostsAdvertising costs are expensed as incurred
Share-Based Compensation	Share-Based Compensation We compensate certain employees and non-employee directors with various forms of share-based payment awards and recognize compensation costs for these awards based on their fair values. We estimate the fair values of certain awards, primarily stock appreciation rights (SARs), on the grant date using the Black-Scholes-Merton option-pricing formula, which incorporates certain assumptions regarding the expected term of an award and expected stock price volatility. We develop the expected term assumption based on the vesting period and contractual term of an award, our historical exercise and cancellation experience, our stock price history, plan provisions that require exercise or cancellation of awards after employees terminate, and the extent to which currently available information indicates that the future is reasonably expected to differ from past experience. We develop the expected volatility assumption based on historical price data for our common stock. We estimate the fair value of certain restricted stock units with service vesting conditions and performance vesting conditions based on the grant date stock price. We estimate the fair value of certain restricted stock units with market conditions using a Monte Carlo simulation valuation model with the assistance of a third party valuation firm. After calculating the aggregate fair value of an award, we use an estimated forfeiture rate to discount the amount of share-based compensation cost expected to be recognized in our operating results over the service period of the award. We develop the forfeiture assumption based on our historical pre-vesting cancellation experience.
Income Taxes	Income Taxes Income taxes are provided based on earnings reported for financial statement purposes. The provision for income taxes differs from the amounts currently payable to taxing authorities because of the recognition of revenues and expenses in different periods for income tax purposes than for financial statement purposes. Income taxes are provided as if operations in all countries, including the U.S., were stand-alone businesses filing separate tax returns. We recognize deferred tax assets resulting from tax credit carryforwards, net operating loss carryforwards, and deductible temporary differences between taxable income on our income tax returns and pretax income on our financial statements. Deferred tax assets generally represent future tax benefits to be received when these carryforwards can be applied against future taxable income or when expenses previously reported in our Consolidated Financial Statements become deductible for income tax purposes. A deferred tax asset valuation allowance is required when some portion or all of the deferred tax assets may not be realized. At December 31, 2020 the valuation allowance of $84.3 million was primarily related to net operating losses, capital losses and foreign tax credits that we do not expect to realize. Our effective tax rate is based on expected income, statutory tax rates, and tax planning opportunities available to us in the various jurisdictions in which we operate. Significant judgment is required in determining our effective tax rate and in evaluating our tax positions. We establish accruals for uncertain tax positions when we believe that the full amount of the associated tax benefit may not be realized. To the extent we were to prevail in matters for which accruals have been established or would be required to pay amounts in excess of reserves, there could be a material effect on our income tax provisions in the period in which such determination is made. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740) Simplifying the Accounting for Income Taxes (“ASU 2019-12”) which removes certain exceptions for investments, intra-period allocations and interim tax calculations, and adds guidance to reduce the complexity in accounting for income taxes. ASU 2019-12 is effective for annual periods beginning after December 15, 2020, with early adoption permitted. The various amendments in ASU 2019-12 are applied on a retrospective basis, modified retrospective basis and prospective basis, depending upon the amendment. The Company did not early adopt this pronouncement and is in the process of evaluating the impact of this amendment on our consolidated financial statements; however, it is not anticipated to be material. See Note 18, Income Taxes, in the accompanying notes to our consolidated financial statements.
Recent Accounting Pronouncements	Current-Year Adoption of Accounting Pronouncements In June 2016, the FASB issued Accounting Standards Update No. 2016-13 (“ASU 2016-13”), Financial Instruments - Credit Losses . Under the new standard, we are required to recognize estimated credit losses expected to occur over the estimated life or remaining contractual life of an asset (which includes losses that may be incurred in future periods) using a broader range of information including past events, current conditions, and reasonable and supportable forecasts about future economic conditions. We adopted ASU 2016-13 on January 1, 2020, which resulted in an increase to our allowance for doubtful accounts for continuing operations of $1.0 million, and an increase for discontinued operations of $1.9 million. See further discussion as well as adjustments to the allowance for doubtful accounts under the new credit loss model in Note 9.

Revenues (Tables)

Revenues (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table presents our revenues disaggregated by major product category (in thousands). Broadband and 5G Cyber-Security Industrial Automation Smart Buildings Total Year Ended December 31, 2020 Enterprise Solutions $ 432,262 $ — $ — $ 440,155 $ 872,417 Industrial Solutions — 110,524 879,775 — 990,299 Total $ 432,262 $ 110,524 $ 879,775 $ 440,155 $ 1,862,716 Year Ended December 31, 2019 Enterprise Solutions $ 401,415 $ — $ — $ 544,626 $ 946,041 Industrial Solutions — 133,039 1,052,198 — 1,185,237 Total $ 401,415 $ 133,039 $ 1,052,198 $ 544,626 $ 2,131,278 Year Ended December 31, 2018 Enterprise Solutions $ 389,246 $ — $ — $ 568,255 $ 957,501 Industrial Solutions — 136,648 1,071,553 — 1,208,201 Total $ 389,246 $ 136,648 $ 1,071,553 $ 568,255 $ 2,165,702 The following tables present our revenues disaggregated by geography, based on the location of the customer purchasing the product (in thousands). Americas EMEA APAC Total Revenues Year Ended December 31, 2020 Enterprise Solutions $ 636,492 $ 130,982 $ 104,943 $ 872,417 Industrial Solutions 577,929 256,673 155,697 990,299 Total $ 1,214,421 $ 387,655 $ 260,640 $ 1,862,716 Year Ended December 31, 2019 Enterprise Solutions $ 695,008 $ 135,732 $ 115,301 $ 946,041 Industrial Solutions 742,563 274,030 168,644 1,185,237 Total $ 1,437,571 $ 409,762 $ 283,945 $ 2,131,278 Year Ended December 31, 2018 Enterprise Solutions $ 700,499 $ 135,217 $ 121,785 $ 957,501 Industrial Solutions 758,165 290,562 159,474 1,208,201 Total $ 1,458,664 $ 425,779 $ 281,259 $ 2,165,702
Contract with Customer, Asset and Liability	The following table presents estimated and accrued variable consideration: December 31, 2020 December 31, 2019 (in thousands) Accrued rebates $ 32,192 $ 37,170 Accrued returns 13,016 10,974 Price adjustment recognized against gross accounts receivable 25,244 28,672 The following table presents deferred revenue activity (in thousands): Balance at December 31, 2018 $ 72,358 New deferrals 111,812 Revenue recognized (114,100) Balance at December 31, 2019 $ 70,070 New deferrals 101,066 Revenue recognized (93,488) Balance at December 31, 2020 $ 77,648

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table summarizes the estimated fair values of the assets acquired and the liabilities assumed as of April 15, 2019 (in thousands): Receivables $ 5,308 Inventory 7,359 Prepaid and other current assets 566 Property, plant, and equipment 1,328 Intangible assets 28,000 Goodwill 35,057 Deferred income taxes 80 Operating lease right-of-use assets 2,204 Other long-lived assets 2,070 Total assets acquired $ 81,972 Accounts payable $ 4,847 Accrued liabilities 4,301 Long-term deferred tax liability 6,813 Long-term operating lease liability 1,923 Other long-term liabilities 7,152 Total liabilities assumed $ 25,036 Net assets $ 56,936 Noncontrolling interest 5,195 Net assets attributable to Belden $ 51,741
Schedule of Acquired Intangible Assets	The intangible assets related to the acquisition consisted of the following: Fair Value Amortization Period (In thousands) (In years) Intangible assets subject to amortization Developed technologies $ 3,400 5 Customer relationships 22,800 15 Sales backlog 1,300 0.5 Trademarks 500 2.0 Total intangible assets subject to amortization $ 28,000 Intangible assets not subject to amortization: Goodwill $ 35,057 Total intangible assets not subject to amortization $ 35,057 Total intangible assets $ 63,057 Weighed average amortization period 12.9
Schedule of Pro Forma Information	The following table illustrates the unaudited pro forma effect on operating results as if the Opterna acquisition had been completed January 1, 2018. Years Ended December 31, 2019 2018 (In thousands, except per share data) (Unaudited) Revenues $ 2,139,894 $ 2,213,781 Net income (loss) attributable to Belden common stockholders (389,957) 123,546 Diluted income (loss) per share attributable to Belden common stockholders $ (9.24) $ 3.02

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2020
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations	The following table summarizes the operating results of the disposal group up to the July 2, 2020 disposal date for the years ended December 31, 2020, 2019 and 2018, respectively: Years Ended December 31, 2020 2019 2018 (In thousands) Revenues $ 109,195 $ 360,496 $ 419,666 Cost of sales (70,199) (208,173) (241,164) Gross profit 38,996 152,323 178,502 Selling, general and administrative expenses (39,947) (93,796) (114,567) Research and development expenses (15,083) (37,172) (49,033) Amortization of intangibles — (12,782) (23,689) Asset impairment of discontinued operations (113,007) (521,441) — Interest expense, net (432) (819) (720) Non-operating pension cost (169) (221) (243) Loss before taxes $ (129,642) $ (513,908) $ (9,750) The following table provides the major classes of assets and liabilities of the disposal group as of December 31, 2019 (in thousands): Assets: Cash and cash equivalents $ 18,405 Receivables, net 117,386 Inventories, net 55,002 Other current assets 35,187 Property, plant and equipment, less accumulated depreciation 61,233 Operating lease right-of-use assets 16,902 Goodwill 26,707 Intangible assets, less accumulated amortization 143,459 Deferred income taxes 59,560 Other long-lived assets 21,652 Impairment of disposal group (180,358) Total assets of discontinued operations $ 375,135 Liabilities: Accounts payable $ 52,425 Accrued liabilities 83,349 Postretirement benefits 6,224 Deferred income taxes 2,740 Long-term operating lease liabilities 20,459 Other long-term liabilities 5,082 Total liabilities of discontinued operations $ 170,279

Operating Segments and Geogra_2

Operating Segments and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Operating Segment Information	Operating Segment Information Enterprise Solutions Years ended December 31, 2020 2019 2018 (In thousands) Segment revenues $ 872,415 $ 946,041 $ 957,501 Affiliate revenues 1,289 4,162 6,105 Segment EBITDA 99,333 126,925 156,790 Depreciation expense 20,655 19,771 18,490 Amortization of intangibles 21,662 22,324 21,076 Amortization of software development intangible assets 245 175 71 Severance, restructuring, and acquisition integration costs 7,720 10,808 14,863 Purchase accounting effects of acquisitions 125 592 1,690 Acquisition of property, plant and equipment 25,223 42,289 42,624 Segment assets 462,615 487,125 430,128 Industrial Solutions Years ended December 31, 2020 2019 2018 (In thousands) Segment revenues $ 990,301 $ 1,185,237 $ 1,208,201 Affiliate revenues 60 11 80 Segment EBITDA 147,626 226,110 237,870 Depreciation expense 21,815 20,638 19,819 Amortization of intangibles 42,733 52,285 54,064 Amortization of software development intangible assets 1,576 350 8 Severance, restructuring, and acquisition integration costs 4,538 15,736 7,762 Acquisition of property, plant and equipment 44,675 35,189 29,529 Segment assets 522,637 504,482 508,843 Total Segments Years ended December 31, 2020 2019 2018 (In thousands) Segment revenues $ 1,862,716 $ 2,131,278 $ 2,165,702 Affiliate revenues 1,349 4,173 6,185 Segment EBITDA 246,959 353,035 394,660 Depreciation expense 42,470 40,409 38,309 Amortization of intangibles 64,395 74,609 75,140 Amortization of software development intangible assets 1,821 525 79 Severance, restructuring, and acquisition integration costs 12,258 26,544 22,625 Purchase accounting effects of acquisitions 125 592 1,690 Acquisition of property, plant and equipment 69,898 77,478 72,153 Segment assets 985,252 991,607 938,971
Reconciliation of Total Reportable Segments' Revenues and EBITDA to Consolidated Revenues and Consolidated Income Before Taxes	The following table is a reconciliation of the total of the reportable segments’ Revenues and EBITDA to consolidated revenues and consolidated income from continuing operations before taxes, respectively. Years Ended December 31, 2020 2019 2018 (In thousands) Total Segment Revenues $ 1,862,716 $ 2,131,278 $ 2,165,702 Deferred revenue adjustments — — — Consolidated Revenues $ 1,862,716 $ 2,131,278 $ 2,165,702 Total Segment EBITDA $ 246,959 $ 353,035 $ 394,660 Amortization of intangibles (64,395) (74,609) (75,140) Depreciation expense (42,470) (40,409) (38,309) Severance, restructuring, and acquisition integration costs (1) (12,258) (26,544) (22,625) Purchase accounting effects related to acquisitions (2) (125) (592) (1,690) Amortization of software development intangible assets (1,821) (525) (79) Loss on sale of assets (3) — — (94) Costs related to patent litigation — — (2,634) Gain from patent litigation — — 62,141 Eliminations (480) (3,149) (2,222) Consolidated operating income 125,410 207,207 314,008 Interest expense, net (58,888) (55,814) (60,839) Non-operating pension benefit (cost) (395) 1,017 (99) Loss on debt extinguishment — — (22,990) Consolidated income from continuing operations before taxes $ 66,127 $ 152,410 $ 230,080 (1) See Note 15, Severance, Restructuring, and Acquisition Integration Activities, for details . (2) In 2020 and 2019, we collectively recognized $0.1 million and $0.6 million, respectively, of cost of sales related to purchase accounting adjustments of acquired inventory to fair value for both our SPC and Opterna acquisitions. In 2018, we made a $1.7 million adjustment to increase the earn-out liability associated with an acquisition. (3) In 2018, we recognized a $0.1 million loss on sale of assets for the sale of our MCS business and Hirschmann JV. See Note 2.
Reconciliations of Other Segment Measures to Consolidated Totals	Below are reconciliations of other segment measures to the consolidated totals. Years Ended December 31, 2020 2019 2018 (In thousands) Total segment assets $ 985,252 $ 991,607 $ 938,971 Cash and cash equivalents 501,994 407,480 407,454 Goodwill 1,251,938 1,243,669 1,206,877 Intangible assets, less accumulated amortization 287,071 339,505 359,931 Deferred income taxes 29,536 25,216 26,459 Corporate assets 83,943 24,147 16,786 Assets of discontinued operations — 375,135 822,843 Total assets $ 3,139,734 $ 3,406,759 $ 3,779,321 Total segment acquisition of property, plant and equipment $ 69,898 $ 77,478 $ 72,153 Discontinued operations acquisition of property, plant and equipment 16,712 29,414 22,681 Corporate acquisition of property, plant and equipment 3,605 3,110 3,013 Total acquisition of property, plant and equipment $ 90,215 $ 110,002 $ 97,847
Schedule of Revenue from External Customers and Long-Lived Assets Based on Physical Location	The table below summarizes net sales and long-lived assets for the years ended December 31, 2020, 2019 and 2018 for the following countries: the U.S., Canada, China, and Germany. No other individual foreign country’s net sales or long-lived assets are material to the Company. United Canada China Germany All Other Total (In thousands, except percentages) Year ended December 31, 2020 Revenues $ 1,015,340 $ 119,700 $ 111,835 $ 91,187 $ 524,654 $ 1,862,716 Percent of total revenues 55 % 6 % 6 % 5 % 28 % 100 % Long-lived assets $ 163,731 $ 32,063 $ 44,824 $ 63,100 $ 114,286 $ 418,004 Year ended December 31, 2019 Revenues $ 1,167,033 $ 162,975 $ 109,522 $ 92,913 $ 598,835 $ 2,131,278 Percent of total revenues 55 % 8 % 5 % 4 % 28 % 100 % Long-lived assets $ 152,214 $ 16,452 $ 40,247 $ 48,272 $ 101,179 $ 358,364 Year ended December 31, 2018 Revenues $ 1,206,401 $ 166,669 $ 107,582 $ 100,691 $ 584,359 $ 2,165,702 Percent of total revenues 56 % 8 % 5 % 4 % 27 % 100 % Long-lived assets $ 170,368 $ 13,352 $ 36,989 $ 39,724 $ 63,776 $ 324,209

Income Per Share (Tables)

Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Basis for Income Per Share Computations	The following table presents the basis of the income per share computations: Years Ended December 31, 2020 2019 2018 (In thousands) Numerator: Income from continuing operations $ 54,403 $ 109,891 $ 167,144 Less: Net income (loss) attributable to noncontrolling interest 104 239 (183) Less: Preferred stock dividends — 18,437 34,931 Income from continuing operations attributable to Belden common stockholders 54,299 91,215 132,396 Add: Loss from discontinued operations, net of tax (99,513) (486,667) (6,433) Add: Loss on disposal of discontinued operations, net of tax (9,948) — — Net income (loss) attributable to Belden common stockholders $ (55,162) $ (395,452) $ 125,963 Denominator: Weighted average shares outstanding, basic 44,778 42,203 40,675 Effect of dilutive common stock equivalents 159 213 281 Weighted average shares outstanding, diluted 44,937 42,416 40,956

Credit Losses (Tables)

Credit Losses (Tables)	12 Months Ended
	Dec. 31, 2020
Credit Loss [Abstract]
Accounts Receivable, Allowance for Credit Loss	The following table presents the activity in the allowance for doubtful accounts for our continuing operations for the year ended December 31, 2020 (in thousands). Balance at December 31, 2019 $ 2,569 Adoption adjustment 1,011 Current period provision 2,282 Recoveries collected (637) Write-offs (114) Currency impact 39 Balance at December 31, 2020 $ 5,150

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2020
Inventory Disclosure [Abstract]
Major Classes of Inventories	The major classes of inventories were as follows: December 31, 2020 2019 (In thousands) Raw materials $ 106,514 $ 98,530 Work-in-process 32,011 34,717 Finished goods 141,042 119,331 Gross inventories 279,567 252,578 Excess and obsolete reserves (32,269) (21,245) Net inventories $ 247,298 $ 231,333

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Summary of Carrying Values of Property, Plant and Equipment	The carrying values of property, plant and equipment were as follows: December 31, 2020 2019 (In thousands) Land and land improvements $ 29,321 $ 27,502 Buildings and leasehold improvements 136,427 126,580 Machinery and equipment 608,618 558,639 Computer equipment and software 137,512 119,533 Construction in process 63,589 70,993 Gross property, plant and equipment 975,467 903,247 Accumulated depreciation (606,847) (557,329) Net property, plant and equipment $ 368,620 $ 345,918

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Components of Lease Expense	The components of lease expense were as follows: Years Ended December 31, 2020 2019 (In thousands) Operating lease cost $ 14,348 $ 14,622 Finance lease cost Amortization of right-of-use asset $ 133 $ 142 Interest on lease liabilities 17 22 Total finance lease cost $ 150 $ 164
Supplemental Cash Flow Information Related To Leases	Supplemental cash flow information related to leases was as follows: Years Ended December 31, 2020 2019 (In thousands) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 15,489 $ 14,594 Operating cash flows from finance leases 16 25 Financing cash flows from finance leases 158 258
Supplemental Balance Sheet Information Related To Leases	Supplemental balance sheet information related to leases was as follows: December 31, 2020 2019 (In thousands, except lease term and discount rate) Operating leases: Total operating lease right-of-use assets $ 54,787 $ 62,251 Accrued liabilities $ 14,742 $ 13,900 Long-term operating lease liabilities 46,398 55,652 Total operating lease liabilities $ 61,140 $ 69,552 Finance leases: Other long-lived assets, at cost $ 764 $ 823 Accumulated depreciation (483) (391) Other long-lived assets, net $ 281 $ 432
Supplemental Other Information Related To Leases	Weighted Average Remaining Lease Term Operating leases 5 years 6 years Finance leases 3 years 3 years Weighted Average Discount Rate Operating leases 6.6% 6.9 % Finance leases 4.9% 6.2 %
Operating Lease, Liability, Maturity	The following table summarizes maturities of lease liabilities as of December 31, 2020 (in thousands): 2021 $ 19,250 2022 16,305 2023 12,552 2024 9,516 2025 8,718 Thereafter 8,901 Total $ 75,242 The following table summarizes maturities of lease liabilities as of December 31, 2019 (in thousands): 2020 $ 19,086 2021 16,988 2022 14,128 2023 11,598 2024 9,032 Thereafter 16,655 Total $ 87,487
Finance Lease, Liability, Maturity	The following table summarizes maturities of lease liabilities as of December 31, 2020 (in thousands): 2021 $ 19,250 2022 16,305 2023 12,552 2024 9,516 2025 8,718 Thereafter 8,901 Total $ 75,242 The following table summarizes maturities of lease liabilities as of December 31, 2019 (in thousands): 2020 $ 19,086 2021 16,988 2022 14,128 2023 11,598 2024 9,032 Thereafter 16,655 Total $ 87,487

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Carrying Value of Intangible Assets	The carrying values of intangible assets were as follows: December 31, 2020 December 31, 2019 Gross Accumulated Net Gross Accumulated Net (In thousands) (In thousands) Goodwill $ 1,251,938 $ — $ 1,251,938 $ 1,243,669 $ — $ 1,243,669 Definite-lived intangible assets subject to amortization: Developed technology $ 428,187 $ (369,849) $ 58,338 $ 413,310 $ (331,696) $ 81,614 Customer relationships 295,382 (128,796) 166,586 297,595 (110,732) 186,863 Trademarks 65,861 (36,539) 29,322 56,393 (30,213) 26,180 In-service research and development 11,536 (9,774) 1,762 10,702 (7,160) 3,542 Backlog 11,421 (11,421) — 11,335 (10,935) 400 Total intangible assets subject to amortization 812,387 (556,379) 256,008 789,335 (490,736) 298,599 Indefinite-lived intangible assets not subject to amortization: Trademarks 31,063 — 31,063 40,106 — 40,106 In-process research and development — — — 800 — 800 Total intangible assets not subject to amortization 31,063 — 31,063 40,906 — 40,906 Intangible assets $ 843,450 $ (556,379) $ 287,071 $ 830,241 $ (490,736) $ 339,505
Changes in Carrying Amount of Goodwill	The changes in the carrying amount of goodwill assigned to reporting units in our reportable segments are as follows: Enterprise Solutions Industrial Solutions Consolidated (In thousands) Balance at December 31, 2018 $ 432,082 $ 774,795 $ 1,206,877 Acquisitions and purchase accounting adjustments 38,209 — 38,209 Translation impact (260) (1,157) (1,417) Balance at December 31, 2019 $ 470,031 $ 773,638 $ 1,243,669 Acquisitions and purchase accounting adjustments 2,420 — 2,420 Translation impact 2,296 3,553 5,849 Balance at December 31, 2020 $ 474,747 $ 777,191 $ 1,251,938
Changes in Carrying Amount of Trademarks	The changes in the carrying amount of indefinite-lived trademarks are as follows: Enterprise Solutions Industrial Solutions Consolidated (In thousands) Balance at December 31, 2018 $ 27,000 $ 13,270 $ 40,270 Translation impact — (164) (164) Balance at December 31, 2019 $ 27,000 $ 13,106 $ 40,106 Reclassify to definite-lived — (9,043) (9,043) Balance at December 31, 2020 $ 27,000 $ 4,063 $ 31,063

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2020
Accrued Liabilities [Abstract]
Carrying Value of Accrued Liabilities	The carrying values of accrued liabilities were as follows: December 31, 2020 2019 (In thousands) Wages, severance and related taxes $ 65,892 $ 58,953 Current deferred revenue 53,371 54,255 Accrued rebates 32,192 37,170 Accrued interest 20,610 18,781 Employee benefits 27,707 17,791 Lease liabilities 14,840 14,072 Other (individual items less than 5% of total current liabilities) 62,029 82,777 Accrued liabilities $ 276,641 $ 283,799

Severance, Restructuring, and_2

Severance, Restructuring, and Acquisition Integration Activities (Tables)	12 Months Ended
	Dec. 31, 2020
Restructuring and Related Activities [Abstract]
Severance, Restructuring and Integration Costs by Segment	The following table summarizes the costs by segment of the programs described above as well as other immaterial programs and acquisition integration activities: Severance Other Restructuring Total Costs (In thousands) Year Ended December 31, 2020 Enterprise Solutions $ 1,345 $ 6,374 $ 7,719 Industrial Solutions 1,706 2,833 4,539 Total $ 3,051 $ 9,207 $ 12,258 Year Ended December 31, 2019 Enterprise Solutions $ 5,018 $ 5,790 $ 10,808 Industrial Solutions 15,736 — 15,736 Total $ 20,754 $ 5,790 $ 26,544 Year Ended December 31, 2018 Enterprise Solutions $ 548 $ 14,315 $ 14,863 Industrial Solutions 240 7,522 7,762 Total $ 788 $ 21,837 $ 22,625 The following table summarizes the costs of the various programs described above as well as other immaterial programs and acquisition integration activities by financial statement line item in the Consolidated Statement of Operations: Years ended December 31, 2020 2019 2018 (In thousands) Cost of sales $ 704 $ 3,425 $ 17,962 Selling, general and administrative expenses 11,554 23,119 4,546 Research and development expenses — — 117 Total $ 12,258 $ 26,544 $ 22,625 Balance at December 31, 2019 $ 19,575 New charges 2,529 Cash payments (4,483) Foreign currency translation (89) Other adjustments (4,147) Balance at March 29, 2020 $ 13,385 New charges 4,660 Cash payments (4,795) Foreign currency translation (132) Other adjustments (1,420) Balance at June 28, 2020 $ 11,698 New charges 2,060 Cash payments (3,968) Foreign currency translation (156) Other adjustments (1,541) Balance at September 27, 2020 $ 8,093 New charges 992 Cash payments (1,823) Foreign currency translation (95) Other adjustments (82) Balance at December 31, 2020 $ 7,085

Long-Term Debt and Other Borr_2

Long-Term Debt and Other Borrowing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Carrying Values of Long-Term Debt and Other Borrowing Arrangements	The carrying values of our long-term debt and other borrowing arrangements were as follows: December 31, 2020 2019 (In thousands) Revolving credit agreement due 2022 $ — $ — Senior subordinated notes: 3.875% Senior subordinated notes due 2028 428,295 392,910 3.375% Senior subordinated notes due 2027 550,665 505,170 4.125% Senior subordinated notes due 2026 244,740 224,520 2.875% Senior subordinated notes due 2025 367,110 336,780 Total senior subordinated notes 1,590,810 1,459,380 Less unamortized debt issuance costs (17,084) (19,896) Long-term debt $ 1,573,726 $ 1,439,484
Schedule of Senior Subordinated Notes	The senior subordinated notes due 2025, 2026, 2027 and 2028 are redeemable after September 15, 2020, October 15, 2021, July 15, 2022, and March 15, 2023, respectively, at the following redemption prices as a percentage of the face amount of the notes: Senior Subordinated Notes due 2025 2026 2027 2028 Year Percentage Year Percentage Year Percentage Year Percentage 2020 101.438 % 2021 102.063 % 2022 101.688 % 2023 101.938 % 2021 100.719 % 2022 101.375 % 2023 101.125 % 2024 101.292 % 2022 and thereafter 100.000 % 2023 100.688 % 2024 100.563 % 2025 100.646 % 2024 and thereafter 100.000 % 2025 and thereafter 100.000 % 2026 and thereafter 100.000 %
Maturities on Outstanding Long-Term Debt and Other Borrowings	Maturities on outstanding long-term debt and other borrowings during each of the five years subsequent to December 31, 2020 are as follows (in thousands): 2021 $ — 2022 — 2023 — 2024 — 2025 367,110 Thereafter 1,223,700 $ 1,590,810

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Components of Income Tax Expense	Years ended December 31, 2020 2019 2018 (in thousands) Income (loss) before taxes: United States operations $ (117,819) $ 42,833 $ 115,500 Foreign operations 183,946 109,577 114,580 Income before taxes $ 66,127 $ 152,410 $ 230,080 Income tax expense (benefit): Currently payable United States federal $ 273 $ 21,893 $ 31,730 United States state and local 91 3,090 3,912 Foreign 11,511 13,859 16,968 11,875 38,842 52,610 Deferred United States federal (1,754) 7,567 7,220 United States state and local (2,310) (1,205) (31) Foreign 3,913 (2,685) 3,137 (151) 3,677 10,326 Income tax expense $ 11,724 $ 42,519 $ 62,936
Effective Income Tax Rate Reconciliation from Continuing Operations	Years Ended December 31, 2020 2019 2018 Effective income tax rate reconciliation from continuing operations: United States federal statutory rate 21.0% 21.0% 21.0% State and local income taxes (2.6)% 1.2% 1.5% Impact of change in tax contingencies 2.3% —% (0.7)% Foreign income tax rate differences (38.2)% (8.6)% (1.0)% Impact of change in deferred tax asset valuation allowance 3.1% 9.2% 0.3% Domestic permanent differences and tax credits 33.9% 5.1% 1.9% Impact of tax reform —% —% 4.4% Impact of CARES act (1.8)% —% —% 17.7% 27.9% 27.4%
Components of Deferred Income Tax Balances	December 31, 2020 2019 (In thousands) Components of deferred income tax balances: Deferred income tax liabilities: Plant, equipment, and intangibles $ (92,271) $ (96,254) Right of use asset (17,610) (16,906) (109,881) (113,160) Deferred income tax assets: Postretirement, pensions, and stock compensation 35,394 28,169 Reserves and accruals 24,388 15,395 Net operating loss, capital loss, and tax credit carryforwards 107,028 76,456 Lease liability 18,515 17,882 Valuation allowances (84,308) (48,251) 101,017 89,651 Net deferred income tax liability $ (8,864) $ (23,509)
Summary of Net Operating Loss Carryforwards	The following tables summarize our net operating losses carryforwards and tax credit carryforwards as of December 31, 2020 by jurisdiction: Net Operating Loss Carryforwards (In thousands) Australia $ 10,546 Germany 15,852 Japan 653 Luxembourg 163 Netherlands 6,578 Other 20,723 United Kingdom 10,720 United States - Federal and various states 140,117 Total $ 205,352
Summary of Tax Credit Carryforwards	Tax Credit Carryforwards (In thousands) United States $ 56,617 Canada 492 Total $ 57,109
Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows: 2020 2019 (In thousands) Balance at beginning of year $ 6,779 $ 6,591 Additions based on tax positions related to the current year 548 488 Additions for tax positions of prior years 1,574 — Reductions for tax positions of prior years - Settlement (328) (300) Balance at end of year $ 8,573 $ 6,779

Pension and Other Postretirem_2

Pension and Other Postretirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Change in Benefit Obligation	The following tables provide a reconciliation of the changes in the plans’ benefit obligations and fair value of assets as well as a statement of the funded status and balance sheet reporting for these plans. Pension Benefits Other Benefits Years Ended December 31, 2020 2019 2020 2019 (In thousands) Change in benefit obligation: Benefit obligation, beginning of year $ (461,352) $ (412,880) $ (29,470) $ (26,143) Service cost (3,930) (3,668) (33) (35) Interest cost (9,729) (12,261) (809) (960) Participant contributions (73) (86) (5) (4) Actuarial loss (42,284) (39,329) (110) (2,374) Divestitures and acquisitions (910) — — — Settlements 26,970 49 — — Curtailments 236 — Plan amendments (226) — — — Foreign currency exchange rate changes (15,345) (9,890) (427) (1,260) Benefits paid 13,718 16,713 1,356 1,306 Benefit obligation, end of year $ (492,925) $ (461,352) $ (29,498) $ (29,470)
Change in Plan Assets	Pension Benefits Other Benefits Years Ended December 31, 2020 2019 2020 2019 (In thousands) Change in plan assets: Fair value of plan assets, beginning of year $ 355,726 $ 311,509 $ — $ — Actual return on plan assets 32,470 45,896 — — Employer contributions 6,393 5,673 1,351 1,302 Plan participant contributions 73 86 5 4 Settlements (26,945) — — — Foreign currency exchange rate changes 7,803 9,275 — — Benefits paid (13,718) (16,713) (1,356) (1,306) Fair value of plan assets, end of year $ 361,802 $ 355,726 $ — $ —
Amounts Recognized in Balance Sheets	Funded status, end of year $ (131,123) $ (105,626) $ (29,498) $ (29,470) Amounts recognized in the balance sheets: Prepaid benefit cost $ 4,780 $ 5,542 $ — $ — Accrued benefit liability, current (3,558) (3,000) (1,443) (1,411) Accrued benefit liability, noncurrent (132,345) (108,168) (28,055) (28,059) Net funded status $ (131,123) $ (105,626) $ (29,498) $ (29,470)
Components of Net Periodic Benefit Costs	The following table provides the components of net periodic benefit costs for the plans. Pension Benefits Other Benefits Years Ended December 31, 2020 2019 2018 2020 2019 2018 (In thousands) Components of net periodic benefit cost: Service cost $ 3,930 $ 3,668 $ 4,579 $ 33 $ 35 $ 47 Interest cost 9,729 12,261 11,480 809 960 945 Expected return on plan assets (16,357) (15,699) (16,389) — — — Amortization of prior service cost (credit) 190 169 (42) — — — Settlement loss (gain) 3,153 (7) 1,342 — — — Net loss (gain) recognition 2,930 1,432 2,775 (59) (133) (12) Net periodic benefit cost $ 3,575 $ 1,824 $ 3,745 $ 783 $ 862 $ 980
Assumptions Used in Determining Benefit Obligations and Net Periodic Benefit Cost Amounts	The following table presents the assumptions used in determining the benefit obligations and the net periodic benefit cost amounts. Pension Benefits Other Benefits Years Ended December 31, Years Ended December 31, 2020 2019 2020 2019 Weighted average assumptions for benefit obligations at year end: Discount rate 1.5 % 2.2 % 2.5 % 2.9 % Salary increase 3.3 % 3.5 % N/A N/A Cash balance interest credit rate 4.6 % 4.0 % N/A N/A Weighted average assumptions for net periodic cost for the year: Discount rate 2.2 % 3.1 % 2.9 % 3.7 % Salary increase 3.5 % 3.6 % N/A N/A Cash balance interest credit rate 4.0 % 4.7 % N/A N/A Expected return on assets 4.9 % 5.0 % N/A N/A Assumed health care cost trend rates: Health care cost trend rate assumed for next year N/A N/A 5.5 % 5.6 % Rate that the cost trend rate gradually declines to N/A N/A 5.0 % 5.0 % Year that the rate reaches the rate it is assumed to remain at N/A N/A 2026 2023
Fair Values of Pension Plan Assets by Asset Category	The following table presents the fair values of the pension plan assets by asset category. December 31, 2020 December 31, 2019 Fair Market Value at December 31, 2020 Quoted Prices Significant Investments Measured at NAV Fair Market Value at December 31, 2019 Quoted Prices Significant Investments Measured at NAV (In thousands) (In thousands) Asset Category: Equity securities(a) U.S. equities fund $ 86,059 $ 3,012 $ — $ 83,047 $ 131,563 $ 2,793 $ — $ 128,770 Non-U.S. equities fund 61,630 5,602 — 56,028 54,496 5,949 — 48,547 Debt securities(b) Government bond fund 98,418 — 772 97,646 74,219 — 745 73,474 Corporate bond fund 82,434 — 12,150 70,284 40,940 — 9,854 31,086 Fixed income fund(c) 7,320 — — 7,320 35,895 — 33,701 2,194 Other investments(d) 17,367 — — 17,367 9,462 — — 9,462 Cash & equivalents 8,574 3,230 — 5,344 9,151 167 — 8,984 Total $ 361,802 $ 11,844 $ 12,922 $ 337,036 $ 355,726 $ 8,909 $ 44,300 $ 302,517 (a) This category includes investments in actively managed and indexed investment funds that invest in a diversified pool of equity securities of companies located in the U.S., Canada, Western Europe and other developed countries throughout the world. The funds are valued using the net asset value method in which an average of the market prices for the underlying investments is used to value the fund. Equity securities held in separate accounts are valued based on observable quoted prices on active exchanges. Funds which are valued using the net asset value method are not included in the fair value hierarchy. (b) This category includes investments in investment funds that invest in U.S. treasuries; other national, state and local government bonds; and corporate bonds of highly rated companies from diversified industries. The funds are valued using the net asset value method in which an average of the market prices for the underlying investments is used to value the fund. Funds valued using the net asset value method are not included in the fair value hierarchy. (c) This category includes guaranteed insurance contracts and annuity policies. (d) This category includes investments in hedge funds that pursue multiple strategies in order to provide diversification and balance risk/return objectives, real estate funds, and private equity funds. Funds valued using the net asset method are not included in the fair value hierarchy.
Benefits Expected to be Paid in Subsequent Years from Our Pension and Other Postretirement as Well as Medicare Subsidy Receipts	The following table reflects the benefits as of December 31, 2020 expected to be paid in each of the next five years and in the aggregate for the five years thereafter from our pension and other postretirement plans. Because our other postretirement plans are unfunded, the anticipated benefits with respect to these plans will come from our own assets. Because our pension plans are primarily funded plans, the anticipated benefits with respect to these plans will come primarily from the trusts established for these plans. Pension Other (In thousands) 2021 $ 19,497 $ 1,460 2022 19,044 1,457 2023 20,320 1,458 2024 21,247 1,463 2025 19,417 1,466 2026-2030 99,881 7,413 Total $ 199,406 $ 14,717
Summary of Accumulated Other Comprehensive Loss and Changes in these Amounts	The pre-tax amounts in accumulated other comprehensive loss that have not yet been recognized as components of net periodic benefit cost at December 31, 2020 and the changes in these amounts during the year ended December 31, 2020 are as follows. Pension Other (In thousands) Components of accumulated other comprehensive loss: Net actuarial loss (gain) $ 80,671 $ (436) Net prior service cost 2,798 — $ 83,469 $ (436) Pension Other (In thousands) Changes in accumulated other comprehensive loss: Net actuarial loss (gain), beginning of year $ 56,746 $ (600) Amortization of actuarial gain (loss) (2,930) 59 Actuarial loss 42,048 110 Asset gain (16,113) — Settlement loss recognized (3,153) — Divestitures and acquisitions 335 — Currency impact 3,738 (5) Net actuarial loss (gain), end of year $ 80,671 $ (436) Prior service cost, beginning of year $ 2,661 $ — Amortization of prior service cost (190) — Prior service cost occurring during the year 226 — Currency impact 101 — Prior service cost, end of year $ 2,798 $ —

Comprehensive Income and Accu_2

Comprehensive Income and Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Components of Other Comprehensive Income (Loss), Net of Tax	The accumulated balances related to each component of other comprehensive income (loss), net of tax, are as follows: Foreign Currency Pension and Other Accumulated Other Comprehensive Income (Loss) (In thousands) Balance at December 31, 2018 $ (41,882) $ (33,025) $ (74,907) Other comprehensive gain (loss) attributable to Belden before reclassifications 23,657 (13,281) 10,376 Amounts reclassified from accumulated other comprehensive income — 1,113 1,113 Net current period other comprehensive gain (loss) attributable to Belden 23,657 (12,168) 11,489 Balance at December 31, 2019 $ (18,225) $ (45,193) $ (63,418) Other comprehensive loss attributable to Belden before reclassifications (123,101) (20,800) (143,901) Amounts reclassified from accumulated other comprehensive income 10,145 5,323 15,468 Net current period other comprehensive loss attributable to Belden (112,956) (15,477) (128,433) Balance at December 31, 2020 $ (131,181) $ (60,670) $ (191,851)
Summary of Effects of Reclassifications from Accumulated Other Comprehensive Income (Loss)	The following table summarizes the effects of reclassifications from accumulated other comprehensive income (loss): Amount Reclassified from Affected Line Item in the (In thousands) Amortization of pension and other postretirement benefit plan items: Settlement loss $ 3,153 (1) Accumulated losses of Grass Valley disposal group 771 (2) Actuarial losses 2,871 (1) Prior service cost 190 (1) Total before tax 6,985 Tax benefit (1,662) Total net of tax $ 5,323 (1) The amortization of these accumulated other comprehensive income (loss) components are included in the computation of net periodic benefit costs (see Note 19). (2) In addition, we reclassified $10.1 million of accumulated foreign currency translation losses associated with the Grass Valley disposal group that are included in the calculation of the loss on disposal of discontinued operations.

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Income Tax Benefit Recognized for our Share-Based Compensation Arrangements	Compensation cost charged against income, primarily selling, general and administrative expense, and the income tax benefit recognized for our share-based compensation arrangements is included below: Years Ended December 31, 2020 2019 2018 (In thousands) Total share-based compensation cost $ 19,171 $ 16,802 $ 17,143 Income tax benefit 4,563 3,999 4,080
Fair Values for SARs and Stock Options Estimated on Grant Date Using Black-Scholes-Merton Option-Pricing Formula Which Incorporates Assumptions	Years Ended December 31, 2020 2019 2018 (In thousands, except weighted average fair Weighted-average fair value of SARs and options granted $ 18.29 $ 22.31 $ 25.19 Total intrinsic value of SARs converted and options exercised 545 354 2,263 Tax benefit (expense) related to share-based compensation (560) (101) 113 Weighted-average fair value of restricted stock shares and units granted 41.75 64.61 72.54 Total fair value of restricted stock shares and units vested 6,600 10,325 5,740 Expected volatility 37.55 % 35.05 % 33.16 % Expected term (in years) 5.7 5.7 5.6 Risk-free rate 1.44 % 2.56 % 2.70 % Dividend yield 0.39 % 0.32 % 0.27 %
Summary of Share Based Compensation Activity	SARs and Stock Options Restricted Shares and Units Number Weighted- Weighted- Aggregate Number Weighted- (In thousands, except exercise prices, fair values, and contractual terms) Outstanding at January 1, 2020 1,367 $ 65.04 n/a n/a 737 $ 68.31 Granted 149 51.14 n/a n/a 565 41.75 Exercised or converted (38) 38.24 n/a n/a (102) 64.56 Forfeited or expired (167) 66.42 n/a n/a (247) 75.07 Outstanding at December 31, 2020 1,311 $ 64.06 5.7 $ (29,054) 953 $ 52.50 Vested or expected to vest at December 31, 2020 1,266 $ 64.09 5.7 $ (28,096) Exercisable or convertible at December 31, 2020 1,021 $ 62.62 5.5 $ (24,060)

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental cash flow information is as follows: Years Ended December 31, 2020 2019 2018 (In thousands) Income tax refunds received $ 4,460 $ 4,695 $ 3,920 Income taxes paid (25,259) (40,760) (52,147) Interest paid (53,029) (51,160) (48,519)

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Details) - 12 months ended Dec. 31, 2020	Segment	segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments	2	2

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details)	Jul. 02, 2020USD ($)	Jul. 19, 2018USD ($)	Jul. 05, 2011patent	Jul. 31, 2015patent	Dec. 31, 2020USD ($)Reporting_Unit	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Jan. 01, 2020USD ($)	Dec. 31, 2017USD ($)
Significant Accounting Policies [Line Items]
Amount of inventory as a percentage of prior year purchases that can be returned by certain distributors					3.00%
Unprocessed adjustments recognized against gross accounts receivables					$ 25,500,000	$ 29,500,000
Unprocessed adjustments recognized against accounts accrued liabilities					13,000,000	11,000,000
Bad debt expense, net of recoveries					2,400,000	100,000	$ 200,000
Allowance for doubtful accounts					5,100,000	2,600,000
Obsolescence and other reserves					$ 32,269,000	21,245,000
Number of reporting units used in quantitative assessment | Reporting_Unit					10
Goodwill impairment loss					$ 0	0	0
Gain on disposal					(9,948,000)	0	0
Accumulated other comprehensive losses recognized as result of sale of equity method investment					191,851,000	63,418,000
Proceeds from disposal of business, net of cash sold					54,821,000	0	40,171,000
Accrued sales rebates					32,192,000	37,170,000
Gain from patent litigation					0	0	62,141,000
Advertising costs					11,600,000	14,700,000	17,000,000
Valuation allowances					84,308,000	48,251,000
Cumulative effect of change in accounting principle					(757,051,000)	(965,819,000)	(1,387,588,000)		$ (1,434,866,000)
Net Operating Losses, Capital Losses and Foreign Tax Credits
Significant Accounting Policies [Line Items]
Valuation allowances					84,300,000
Retained Earnings
Significant Accounting Policies [Line Items]
Cumulative effect of change in accounting principle					(450,876,000)	(518,004,000)	(922,000,000)		(833,610,000)
Cumulative Effect, Period of Adoption, Adjustment
Significant Accounting Policies [Line Items]
Cumulative effect of change in accounting principle						2,916,000	29,041,000
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings
Significant Accounting Policies [Line Items]
Cumulative effect of change in accounting principle						2,916,000	29,041,000	$ 2,900,000
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings | Continuing Operations
Significant Accounting Policies [Line Items]
Cumulative effect of change in accounting principle								1,000,000
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings | Discontinued Operations
Significant Accounting Policies [Line Items]
Cumulative effect of change in accounting principle								1,900,000
Subsidiaries | Corning
Significant Accounting Policies [Line Items]
Number of patents allegedly infringed upon | patent			2
Proceeds from settlement		$ 62,100,000
Number of patents found infringed upon | patent				2
Grass Valley
Significant Accounting Policies [Line Items]
Impairment of the disposal group					113,000,000	521,400,000
Grass Valley | Discontinued Operations, Disposed of by Sale
Significant Accounting Policies [Line Items]
Proceeds from disposal of business, net of cash sold	$ 56,200,000
Grass Valley | Discontinued Operations, Held-for-sale
Significant Accounting Policies [Line Items]
Goodwill impairment loss						326,100,000
Impairment of the disposal group					113,007,000	$ 521,441,000	0
Previously Closed Operating Facility | Discontinued Operations, Disposed of by Sale
Significant Accounting Policies [Line Items]
Disposition, sales price					2,100,000		1,500,000
Gain on disposal					$ 400,000		600,000
Hirschmann Jv | Discontinued Operations, Held-for-sale
Significant Accounting Policies [Line Items]
Disposition, sales price									$ 40,200,000
Proceeds from disposal of business, net of cash sold							$ 40,200,000
Minimum
Significant Accounting Policies [Line Items]
Estimated useful life of definite-lived intangible assets					1 year
Maximum
Significant Accounting Policies [Line Items]
Estimated useful life of definite-lived intangible assets					25 years
Buildings | Minimum
Significant Accounting Policies [Line Items]
Estimated useful life of property, plant, and equipment					10
Buildings | Maximum
Significant Accounting Policies [Line Items]
Estimated useful life of property, plant, and equipment					40 years
Machinery and equipment | Minimum
Significant Accounting Policies [Line Items]
Estimated useful life of property, plant, and equipment					5
Machinery and equipment | Maximum
Significant Accounting Policies [Line Items]
Estimated useful life of property, plant, and equipment					12 years
Computer Equipment and Software | Minimum
Significant Accounting Policies [Line Items]
Estimated useful life of property, plant, and equipment					5
Computer Equipment and Software | Maximum
Significant Accounting Policies [Line Items]
Estimated useful life of property, plant, and equipment					10 years
Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings | Continuing Operations
Significant Accounting Policies [Line Items]
Cumulative effect of change in accounting principle								1,000,000
Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings | Discontinued Operations
Significant Accounting Policies [Line Items]
Cumulative effect of change in accounting principle								$ 1,900,000
Hirschmann Jv
Significant Accounting Policies [Line Items]
Equity method investment, ownership percentage									50.00%

Revenues - Narrative (Details)

Revenues - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Increase (decrease) in retained earnings	$ 450,876	$ 518,004
Contract with customer, deferred revenues	77,648	70,070	$ 72,358
Contract with customer, deferred revenues, current	53,371	54,255
Contract with customer, deferred revenues, noncurrent	24,200
Deferred sales commission	5,800	3,400	2,900
Sales commissions	16,300	$ 19,000	$ 20,300
Service-Type Warranties [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with customer, deferred revenues	10,400
Contract with customer, deferred revenues, current	3,600
Contract with customer, deferred revenues, noncurrent	$ 6,800
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Increase (decrease) in retained earnings				$ 2,600

Revenues - Major Product Catego

Revenues - Major Product Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 1,862,716	$ 2,131,278	$ 2,165,702
Enterprise Solutions
Disaggregation of Revenue [Line Items]
Revenues	872,417	946,041	957,501
Industrial Solutions
Disaggregation of Revenue [Line Items]
Revenues	990,299	1,185,237	1,208,201
Broadband and 5G
Disaggregation of Revenue [Line Items]
Revenues	432,262	401,415	389,246
Broadband and 5G | Enterprise Solutions
Disaggregation of Revenue [Line Items]
Revenues	432,262	401,415	389,246
Broadband and 5G | Industrial Solutions
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Cyber-Security
Disaggregation of Revenue [Line Items]
Revenues	110,524	133,039	136,648
Cyber-Security | Enterprise Solutions
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Cyber-Security | Industrial Solutions
Disaggregation of Revenue [Line Items]
Revenues	110,524	133,039	136,648
Industrial Automation
Disaggregation of Revenue [Line Items]
Revenues	879,775	1,052,198	1,071,553
Industrial Automation | Enterprise Solutions
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Industrial Automation | Industrial Solutions
Disaggregation of Revenue [Line Items]
Revenues	879,775	1,052,198	1,071,553
Smart Buildings
Disaggregation of Revenue [Line Items]
Revenues	440,155	544,626	568,255
Smart Buildings | Enterprise Solutions
Disaggregation of Revenue [Line Items]
Revenues	440,155	544,626	568,255
Smart Buildings | Industrial Solutions
Disaggregation of Revenue [Line Items]
Revenues	$ 0	$ 0	$ 0

Revenues - Location of Customer

Revenues - Location of Customer (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 1,862,716	$ 2,131,278	$ 2,165,702
Enterprise Solutions
Disaggregation of Revenue [Line Items]
Revenues	872,417	946,041	957,501
Industrial Solutions
Disaggregation of Revenue [Line Items]
Revenues	990,299	1,185,237	1,208,201
Americas
Disaggregation of Revenue [Line Items]
Revenues	1,214,421	1,437,571	1,458,664
Americas | Enterprise Solutions
Disaggregation of Revenue [Line Items]
Revenues	636,492	695,008	700,499
Americas | Industrial Solutions
Disaggregation of Revenue [Line Items]
Revenues	577,929	742,563	758,165
EMEA
Disaggregation of Revenue [Line Items]
Revenues	387,655	409,762	425,779
EMEA | Enterprise Solutions
Disaggregation of Revenue [Line Items]
Revenues	130,982	135,732	135,217
EMEA | Industrial Solutions
Disaggregation of Revenue [Line Items]
Revenues	256,673	274,030	290,562
APAC
Disaggregation of Revenue [Line Items]
Revenues	260,640	283,945	281,259
APAC | Enterprise Solutions
Disaggregation of Revenue [Line Items]
Revenues	104,943	115,301	121,785
APAC | Industrial Solutions
Disaggregation of Revenue [Line Items]
Revenues	$ 155,697	$ 168,644	$ 159,474

Revenues - Estimated and Accrue

Revenues - Estimated and Accrued Variable Concideration (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Accrued rebates	$ 32,192	$ 37,170
Accrued returns	13,016	10,974
Price adjustment recognized against gross accounts receivable	$ 25,244	$ 28,672

Revenues Revenues - Deferred Re

Revenues Revenues - Deferred Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Change in Contract with Customer, Liability [Roll Forward]
Beginning Balance	$ 70,070	$ 72,358
New deferrals	101,066	111,812
Revenue recognized	(93,488)	(114,100)
Ending Balance	$ 77,648	$ 70,070

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details) - USD ($) $ in Thousands	Dec. 06, 2019	Oct. 25, 2019	Apr. 15, 2019	Apr. 05, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Cash used to acquire businesses, net of cash acquired						$ (590)	$ 74,392	$ 84,580
Severance, restructuring, and acquisition integration costs						12,258	26,544	22,625
Amortization of intangibles						64,395	74,609	75,140
Net income (loss)						(55,058)	$ (376,776)	160,711
Opterna International Corp.
Business Acquisition [Line Items]
Cash used to acquire businesses, net of cash acquired			$ 51,700
Percentage of outstanding shares acquired			100.00%
Acquisition price paid						45,900
Maximum earnout consideration			$ 25,000
Estimated earnout consideration			5,800
Payments to acquire interest in subsidiaries		$ 400
Noncontrolling interest, purchase price		$ 800
Fair value of acquired receivables			$ 5,308			$ 5,300
Severance, restructuring, and acquisition integration costs								5,500
Amortization of intangibles								3,800
Inventory adjustment								$ 500
Suttle, Inc. Asset Acquisition
Business Acquisition [Line Items]
Asset acquisition, consideration transferred				$ 5,000
Special Product Company (SPC)
Business Acquisition [Line Items]
Cash used to acquire businesses, net of cash acquired	$ 22,500
Scenario, Forecast | Opterna International Corp.
Business Acquisition [Line Items]
Payments to acquire interest in subsidiaries					$ 400

Acquisitions - Schedule of Reco

Acquisitions - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Apr. 15, 2019	Dec. 31, 2018
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Goodwill	$ 1,251,938	$ 1,243,669		$ 1,206,877
Opterna International Corp.
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Receivables	$ 5,300		$ 5,308
Inventory			7,359
Prepaid and other current assets			566
Property, plant, and equipment			1,328
Intangible assets			28,000
Goodwill			35,057
Deferred income taxes			80
Operating lease right-of-use assets			2,204
Other long-lived assets			2,070
Total assets acquired			81,972
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Accounts payable			4,847
Accrued liabilities			4,301
Long-term deferred tax liability			6,813
Long-term operating lease liability			1,923
Other long-term liabilities			7,152
Total liabilities assumed			25,036
Net assets			56,936
Noncontrolling interest			5,195
Net assets attributable to Belden			$ 51,741

Acquisitions - Schedule of Acqu

Acquisitions - Schedule of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Apr. 15, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Acquired Finite And Indefinite Lived Intangible Assets [Line Items]
Goodwill		$ 1,251,938	$ 1,243,669	$ 1,206,877
Developed technologies
Acquired Finite And Indefinite Lived Intangible Assets [Line Items]
Amortization Period		6 years 9 months 18 days
Customer relationships
Acquired Finite And Indefinite Lived Intangible Assets [Line Items]
Amortization Period		18 years 2 months 12 days
Trademarks
Acquired Finite And Indefinite Lived Intangible Assets [Line Items]
Amortization Period		8 years 3 months 18 days
Opterna International Corp.
Acquired Finite And Indefinite Lived Intangible Assets [Line Items]
Total intangible assets subject to amortization	$ 28,000
Goodwill	35,057
Total intangible assets	$ 63,057
Amortization Period	12 years 10 months 24 days
Opterna International Corp. | Goodwill
Acquired Finite And Indefinite Lived Intangible Assets [Line Items]
Goodwill	$ 35,057
Opterna International Corp. | Developed technologies
Acquired Finite And Indefinite Lived Intangible Assets [Line Items]
Total intangible assets subject to amortization	$ 3,400
Amortization Period	5 years
Opterna International Corp. | Customer relationships
Acquired Finite And Indefinite Lived Intangible Assets [Line Items]
Total intangible assets subject to amortization	$ 22,800
Amortization Period	15 years
Opterna International Corp. | Sales backlog
Acquired Finite And Indefinite Lived Intangible Assets [Line Items]
Total intangible assets subject to amortization	$ 1,300
Amortization Period	6 months
Opterna International Corp. | Trademarks
Acquired Finite And Indefinite Lived Intangible Assets [Line Items]
Total intangible assets subject to amortization	$ 500
Amortization Period	2 years

Acquisitions - Schedule of Pro

Acquisitions - Schedule of Pro Forma Information (Details) - Opterna International Corp. - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Revenues	$ 2,139,894	$ 2,213,781
Net income (loss) attributable to Belden common stockholders	$ (389,957)	$ 123,546
Diluted income (loss) per share attributable to Belden common stockholders (in dollars per share)	$ (9.24)	$ 3.02

Discontinued Operations - Addit

Discontinued Operations - Additional Information (Details) - USD ($)	Jul. 02, 2020	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill impairment loss			$ 0	$ 0	$ 0
Proceeds from disposal of business, net of cash sold			54,821,000	0	40,171,000
Depreciation and amortization			0	23,700,000	35,100,000
Capital expenditure			16,700,000	29,400,000	22,600,000
Share-based compensation expense			(900,000)	900,000	1,400,000
Accumulated other comprehensive income (loss), net of tax				42,300,000
Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of the disposal group				179,300,000
Translation exchange rates				180,400,000
Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on sale, discontinued operations	$ 9,900,000
Tax effect of discontinued operation	7,500,000
Grass Valley
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of the disposal group			113,000,000	521,400,000
Equity interest in divested business	$ 3,000,000
Equity interest in divested business, percentage	9.00%
Proceeds from sale of equity interest under cost method		$ 2,700,000
Accrued interest		7,800,000
Revenues		$ 2,000,000
Grass Valley | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of the disposal group			113,007,000	521,441,000	0
Goodwill impairment loss				326,100,000
Impairment of the disposal group			179,300,000
Translation exchange rates			180,400,000
Revenues			109,195,000	360,496,000	$ 419,666,000
Grass Valley | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses	$ 120,000,000
Proceeds from disposal of business, net of cash sold	56,200,000
Deferred consideration - seller's note	175,000,000
Paid-in-kind interest	88,000,000
Deferred compensation - earnout payments	178,000,000
Fair value of debt instrument	$ 34,900,000
Payment in kind, annual interest rate	0.085
Customer relationships | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of intangible assets				14,400,000
Customer relationships | Grass Valley | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of intangible assets			14,400,000
Trademarks | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of intangible assets				$ 1,600,000
Trademarks | Grass Valley | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of intangible assets			$ 1,600,000

Discontinued Operations - Opera

Discontinued Operations - Operating Results of the Disposal Group (Details) - Grass Valley - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues	$ 2,000
Asset impairment of discontinued operations		$ (113,000)	$ (521,400)
Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues		109,195	360,496	$ 419,666
Cost of sales		(70,199)	(208,173)	(241,164)
Gross profit		38,996	152,323	178,502
Selling, general and administrative expenses		(39,947)	(93,796)	(114,567)
Research and development expenses		(15,083)	(37,172)	(49,033)
Amortization of intangibles		0	(12,782)	(23,689)
Asset impairment of discontinued operations		(113,007)	(521,441)	0
Interest expense, net		(432)	(819)	(720)
Non-operating pension cost		(169)	(221)	(243)
Loss before taxes		$ (129,642)	$ (513,908)	$ (9,750)

Discontinued Operations - Asset

Discontinued Operations - Assets and Liabilities of the Disposal Group (Details) - Grass Valley - Discontinued Operations, Held-for-sale $ in Thousands	Dec. 31, 2019USD ($)
Assets:
Cash and cash equivalents	$ 18,405
Receivables, net	117,386
Inventories, net	55,002
Other current assets	35,187
Property, plant and equipment, less accumulated depreciation	61,233
Operating lease right-of-use assets	16,902
Goodwill	26,707
Intangible assets, less accumulated amortization	143,459
Deferred income taxes	59,560
Other long-lived assets	21,652
Impairment of disposal group	(180,358)
Total assets of discontinued operations	375,135
Liabilities:
Accounts payable	52,425
Accrued liabilities	83,349
Postretirement benefits	6,224
Deferred income taxes	2,740
Long-term operating lease liabilities	20,459
Other long-term liabilities	5,082
Total liabilities of discontinued operations	$ 170,279

Operating Segments and Geogra_3

Operating Segments and Geographic Information - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)Segment	Dec. 31, 2020USD ($)	Dec. 31, 2020USD ($)segment	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments	2		2
Revenues		$ 1,862,716			$ 2,131,278	$ 2,165,702
Anixter International Inc.
Segment Reporting Information [Line Items]
Accounts receivable outstanding	$ 17,500	$ 17,500	$ 17,500	$ 17,500
Anixter International Inc. | Customer Concentration Risk
Segment Reporting Information [Line Items]
Percentage of total accounts receivable outstanding	6.00%	6.00%	6.00%	6.00%
Anixter International Inc and WESCO
Segment Reporting Information [Line Items]
Revenues		$ 271,600			$ 328,200	$ 361,700
Anixter International Inc and WESCO | Customer Concentration Risk | Revenues
Segment Reporting Information [Line Items]
Percent of total revenues				15.00%	15.00%	17.00%

Operating Segments and Geogra_4

Operating Segments and Geographic Information - Operating Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenues	$ 1,862,716	$ 2,131,278	$ 2,165,702
Depreciation expense	42,500	40,400	38,300
Amortization of intangibles	64,395	74,609	75,140
Severance, restructuring, and acquisition integration costs	12,258	26,544	22,625
Acquisition of property, plant and equipment	90,215	110,002	97,847
Segment assets	3,139,734	3,406,759	3,779,321
Enterprise Solutions
Segment Reporting Information [Line Items]
Revenues	872,417	946,041	957,501
Severance, restructuring, and acquisition integration costs	7,719	10,808	14,863
Industrial Solutions
Segment Reporting Information [Line Items]
Revenues	990,299	1,185,237	1,208,201
Severance, restructuring, and acquisition integration costs	4,539	15,736	7,762
Reportable Segment
Segment Reporting Information [Line Items]
Revenues	1,862,716	2,131,278	2,165,702
Segment EBITDA	246,959	353,035	394,660
Depreciation expense	42,470	40,409	38,309
Amortization of intangibles	64,395	74,609	75,140
Amortization of software development intangible assets	1,821	525	79
Severance, restructuring, and acquisition integration costs	12,258	26,544	22,625
Purchase accounting effects of acquisitions	125	592	1,690
Acquisition of property, plant and equipment	69,898	77,478	72,153
Segment assets	985,252	991,607	938,971
Reportable Segment | Enterprise Solutions
Segment Reporting Information [Line Items]
Segment EBITDA	99,333	126,925	156,790
Depreciation expense	20,655	19,771	18,490
Amortization of intangibles	21,662	22,324	21,076
Severance, restructuring, and acquisition integration costs	7,720	10,808	14,863
Purchase accounting effects of acquisitions	125	592	1,690
Acquisition of property, plant and equipment	25,223	42,289	42,624
Segment assets	462,615	487,125	430,128
Reportable Segment | Industrial Solutions
Segment Reporting Information [Line Items]
Segment EBITDA	147,626	226,110	237,870
Depreciation expense	21,815	20,638	19,819
Amortization of intangibles	42,733	52,285	54,064
Severance, restructuring, and acquisition integration costs	4,538	15,736	7,762
Acquisition of property, plant and equipment	44,675	35,189	29,529
Segment assets	522,637	504,482	508,843
Software Development | Reportable Segment
Segment Reporting Information [Line Items]
Amortization of intangibles	1,821	525	79
Software Development | Reportable Segment | Enterprise Solutions
Segment Reporting Information [Line Items]
Amortization of software development intangible assets	245	175	71
Software Development | Reportable Segment | Industrial Solutions
Segment Reporting Information [Line Items]
Amortization of software development intangible assets	1,576	350	8
Segment revenues | Reportable Segment
Segment Reporting Information [Line Items]
Revenues	1,862,716	2,131,278	2,165,702
Segment revenues | Reportable Segment | Enterprise Solutions
Segment Reporting Information [Line Items]
Revenues	872,415	946,041	957,501
Segment revenues | Reportable Segment | Industrial Solutions
Segment Reporting Information [Line Items]
Revenues	990,301	1,185,237	1,208,201
Affiliate revenues | Reportable Segment
Segment Reporting Information [Line Items]
Revenues	1,349	4,173	6,185
Affiliate revenues | Reportable Segment | Enterprise Solutions
Segment Reporting Information [Line Items]
Revenues	1,289	4,162	6,105
Affiliate revenues | Reportable Segment | Industrial Solutions
Segment Reporting Information [Line Items]
Revenues	$ 60	$ 11	$ 80

Operating Segments and Geogra_5

Operating Segments and Geographic Information - Reconciliation of Total Reportable Segments' Revenues and EBITDA to Consolidated Revenues and Consolidated Income Before Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Segment Revenues	$ 1,862,716	$ 2,131,278	$ 2,165,702
Amortization of intangibles	(64,395)	(74,609)	(75,140)
Depreciation expense	(42,500)	(40,400)	(38,300)
Severance, restructuring, and acquisition integration costs	(12,258)	(26,544)	(22,625)
Gain from patent litigation	0	0	62,141
Operating income	125,410	207,207	314,008
Interest expense, net	(58,888)	(55,814)	(60,839)
Non-operating pension benefit (cost)	(395)	1,017	(99)
Loss on debt extinguishment	0	0	(22,990)
Consolidated income from continuing operations before taxes	66,127	152,410	230,080
Reportable Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Segment Revenues	1,862,716	2,131,278	2,165,702
Deferred revenue adjustments	0	0	0
Total Segment EBITDA	246,959	353,035	394,660
Amortization of intangibles	(64,395)	(74,609)	(75,140)
Depreciation expense	(42,470)	(40,409)	(38,309)
Severance, restructuring, and acquisition integration costs	(12,258)	(26,544)	(22,625)
Purchase accounting effects related to acquisitions	(125)	(592)	(1,690)
Amortization of software development intangible assets	(1,821)	(525)	(79)
Loss on sale of assets	0	0	(94)
Costs related to patent litigation	0	0	(2,634)
Gain from patent litigation	0	0	62,141
Operating income	125,410	207,207	314,008
Interest expense, net	(58,888)	(55,814)	(60,839)
Eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income	(480)	(3,149)	(2,222)
Segment revenues | Reportable Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Segment Revenues	$ 1,862,716	$ 2,131,278	$ 2,165,702

Operating Segments and Geogra_6

Operating Segments and Geographic Information - Reconciliations of Other Segment Measures to Consolidated Totals (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment assets	$ 3,139,734	$ 3,406,759	$ 3,779,321
Cash and cash equivalents	501,994	407,480	407,454
Goodwill	1,251,938	1,243,669	1,206,877
Intangible assets, less accumulated amortization	287,071	339,505	359,931
Deferred income taxes	29,536	25,216	26,459
Payments to acquire property, plant, and equipment from continuing operations	90,215	110,002	97,847
Discontinued operations acquisition of property, plant and equipment	16,712	29,414	22,681
Reportable Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment assets	985,252	991,607	938,971
Payments to acquire property, plant, and equipment from continuing operations	69,898	77,478	72,153
Corporate assets
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment assets	83,943	24,147	16,786
Assets of discontinued operations	0	375,135	822,843
Payments to acquire property, plant, and equipment from continuing operations	$ 3,605	$ 3,110	$ 3,013

Operating Segments and Geogra_7

Operating Segments and Geographic Information - Schedule of Revenue from External Customers and Long-Lived Assets Based on Physical Location (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Segment Revenues	$ 1,862,716	$ 2,131,278	$ 2,165,702
Percent of total revenues	100.00%	100.00%	100.00%
Long-lived assets	$ 418,004	$ 358,364	$ 324,209
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Segment Revenues	$ 1,015,340	$ 1,167,033	$ 1,206,401
Percent of total revenues	55.00%	55.00%	56.00%
Long-lived assets	$ 163,731	$ 152,214	$ 170,368
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Segment Revenues	$ 119,700	$ 162,975	$ 166,669
Percent of total revenues	6.00%	8.00%	8.00%
Long-lived assets	$ 32,063	$ 16,452	$ 13,352
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Segment Revenues	$ 111,835	$ 109,522	$ 107,582
Percent of total revenues	6.00%	5.00%	5.00%
Long-lived assets	$ 44,824	$ 40,247	$ 36,989
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Segment Revenues	$ 91,187	$ 92,913	$ 100,691
Percent of total revenues	5.00%	4.00%	4.00%
Long-lived assets	$ 63,100	$ 48,272	$ 39,724
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Segment Revenues	$ 524,654	$ 598,835	$ 584,359
Percent of total revenues	28.00%	28.00%	27.00%
Long-lived assets	$ 114,286	$ 101,179	$ 63,776

Noncontrolling Interest - Addit

Noncontrolling Interest - Additional Information (Details) - USD ($) $ in Thousands	Oct. 25, 2019	Dec. 31, 2021	Dec. 31, 2020
Opterna International Corp.
Noncontrolling Interest [Line Items]
Noncontrolling interest, purchase price	$ 800
Payments to acquire interest in subsidiaries	$ 400
Variable Interest Entity, primary beneficiary Belden
Noncontrolling Interest [Line Items]
Additional contribution commitments to joint venture			$ 1,530
Hite
Noncontrolling Interest [Line Items]
Additional contribution commitments to joint venture			$ 1,470
Scenario, Forecast | Opterna International Corp.
Noncontrolling Interest [Line Items]
Payments to acquire interest in subsidiaries		$ 400
Hite | Hite | Variable Interest Entity, primary beneficiary Belden
Noncontrolling Interest [Line Items]
Variable interest entity, ownership percentage			51.00%

Income Per Share - Basis for In

Income Per Share - Basis for Income Per Share Computations (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Income from continuing operations	$ 54,403	$ 109,891	$ 167,144
Less: Net income (loss) attributable to noncontrolling interest	104	239	(183)
Less: Preferred stock dividends	0	18,437	34,931
Income from continuing operations attributable to Belden common stockholders	54,299	91,215	132,396
Loss from discontinued operations, net of tax	(99,513)	(486,667)	(6,433)
Gain on disposal	(9,948)	0	0
Net income (loss) attributable to Belden common stockholders	$ (55,162)	$ (395,452)	$ 125,963
Denominator:
Weighted average shares outstanding, basic (in shares)	44,778	42,203	40,675
Effect of dilutive common stock equivalents (in shares)	159	213	281
Weighted average shares outstanding, diluted (in shares)	44,937	42,416	40,956

Income Per Share - Additional I

Income Per Share - Additional Information (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from diluted weighted average shares outstanding (in shares)	1.5	1.2	0.9
Anti-dilutive shares excluded form diluted weighted average shares outstanding due to performance conditions not met (in shares)	0.4	0.3	0.3
Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from diluted weighted average shares outstanding (in shares)	3.7	6.9

Credit Losses (Details)

Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Credit Loss [Line Items]
Cumulative effect of change in accounting principle	$ (757,051)		$ (965,819)	$ (1,387,588)	$ (1,434,866)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Accounts receivable, allowance for credit loss, beginning balance	2,569
Incease to allowance for doubtful accounts	2,282
Recoveries collected	(637)
Write-offs	(114)
Currency impact	39
Accounts receivable, allowance for credit loss, ending balance	5,150
Revision of Prior Period, Accounting Standards Update, Adjustment
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Accounts receivable, allowance for credit loss, beginning balance	1,011
Cumulative Effect, Period of Adoption, Adjustment
Credit Loss [Line Items]
Cumulative effect of change in accounting principle			2,916	29,041
Retained Earnings
Credit Loss [Line Items]
Cumulative effect of change in accounting principle	$ (450,876)		(518,004)	(922,000)	$ (833,610)
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
Credit Loss [Line Items]
Cumulative effect of change in accounting principle		$ 2,900	$ 2,916	$ 29,041
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment | Continuing Operations
Credit Loss [Line Items]
Cumulative effect of change in accounting principle		1,000
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment | Discontinued Operations
Credit Loss [Line Items]
Cumulative effect of change in accounting principle		$ 1,900

Inventories - Major Classes of

Inventories - Major Classes of Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 106,514	$ 98,530
Work-in-process	32,011	34,717
Finished goods	141,042	119,331
Gross inventories	279,567	252,578
Excess and obsolete reserves	(32,269)	(21,245)
Net inventories	$ 247,298	$ 231,333

Property, Plant and Equipment -

Property, Plant and Equipment - Summary of Carrying Values of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 975,467	$ 903,247
Accumulated depreciation	(606,847)	(557,329)
Net property, plant and equipment	368,620	345,918
Land and land improvements
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	29,321	27,502
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	136,427	126,580
Machinery and equipment
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	608,618	558,639
Computer equipment and software
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	137,512	119,533
Construction in process
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 63,589	$ 70,993

Property, Plant and Equipment_2

Property, Plant and Equipment - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 42.5	$ 40.4	$ 38.3

Leases Additional Information (

Leases Additional Information (Details)	12 Months Ended
	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Renewal term	15 years
Minimum
Lessee, Lease, Description [Line Items]
Operating and finance lease, term of contract	1 year

Leases Components of Lease Expe

Leases Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease cost	$ 14,348	$ 14,622
Amortization of right-of-use asset	133	142
Interest on lease liabilities	17	22
Total finance lease cost	$ (150)	$ (164)

Leases Supplemental Cash Flow I

Leases Supplemental Cash Flow Information Related To Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating cash flows from operating leases	$ 15,489	$ 14,594
Operating cash flows from finance leases	16	25
Financing cash flows from finance leases	$ 158	$ 258

Leases Supplemental Balance She

Leases Supplemental Balance Sheet Information Related To Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease right-of-use assets	$ 54,787	$ 62,251
Accrued liabilities	14,742	13,900
Long-term operating lease liabilities	46,398	55,652
Total operating lease liabilities	61,140	69,552
Other long-lived assets, at cost	764	823
Accumulated depreciation	(483)	(391)
Other long-lived assets, net	$ 281	$ 432
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:LiabilitiesCurrentAbstract	us-gaap:LiabilitiesCurrentAbstract
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssets

Leases Supplemental Other Infor

Leases Supplemental Other Information Related To Leases (Details)	Dec. 31, 2020	Dec. 31, 2019
Weighted Average Remaining Lease Term
Operating leases	5 years	6 years
Finance leases	3 years	3 years
Weighted Average Discount Rate
Operating leases	6.60%	6.90%
Finance leases	4.90%	6.20%

Leases Maturities of Lease Liab

Leases Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Operating and Finance Leases
Lease liability, year one	$ 19,250	$ 19,086
Lease liability, year two	16,305	16,988
Lease liability, year three	12,552	14,128
Lease liability, year four	9,516	11,598
Lease liability, year five	8,718	9,032
Thereafter	8,901	16,655
Total	$ 75,242	$ 87,487

Intangible Assets - Carrying Va

Intangible Assets - Carrying Value of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Intangible Assets [Line Items]
Goodwill, Gross carrying amount	$ 1,251,938	$ 1,243,669
Goodwill, Accumulated Amortization	0	0
Goodwill, Net Carrying Amount	1,251,938	1,243,669	$ 1,206,877
Finite-lived intangible assets, Gross Carrying Amount	812,387	789,335
Finite-lived intangible assets, Accumulated Amortization	(556,379)	(490,736)
Finite-lived intangible assets, Net Carrying Amount	256,008	298,599
Indefinite-lived intangible assets, Carrying Amount	31,063	40,906
Intangible assets, Gross Carrying Amount	843,450	830,241
Intangible assets, Net Carrying Amount	287,071	339,505	$ 359,931
Trademarks
Intangible Assets [Line Items]
Indefinite-lived intangible assets, Carrying Amount	31,063	40,106
In-process research and development
Intangible Assets [Line Items]
Indefinite-lived intangible assets, Carrying Amount	0	800
Developed technologies
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Carrying Amount	428,187	413,310
Finite-lived intangible assets, Accumulated Amortization	(369,849)	(331,696)
Finite-lived intangible assets, Net Carrying Amount	58,338	81,614
Customer relationships
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Carrying Amount	295,382	297,595
Finite-lived intangible assets, Accumulated Amortization	(128,796)	(110,732)
Finite-lived intangible assets, Net Carrying Amount	166,586	186,863
Trademarks
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Carrying Amount	65,861	56,393
Finite-lived intangible assets, Accumulated Amortization	(36,539)	(30,213)
Finite-lived intangible assets, Net Carrying Amount	29,322	26,180
In-process research and development
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Carrying Amount	11,536	10,702
Finite-lived intangible assets, Accumulated Amortization	(9,774)	(7,160)
Finite-lived intangible assets, Net Carrying Amount	1,762	3,542
Backlog
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Carrying Amount	11,421	11,335
Finite-lived intangible assets, Accumulated Amortization	(11,421)	(10,935)
Finite-lived intangible assets, Net Carrying Amount	$ 0	$ 400

Intangible Assets - Changes in

Intangible Assets - Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 1,243,669	$ 1,206,877
Acquisitions and purchase accounting adjustments	2,420	38,209
Translation impact	5,849	(1,417)
Goodwill, Ending Balance	1,251,938	1,243,669
Enterprise Solutions
Goodwill [Roll Forward]
Goodwill, Beginning Balance	470,031	432,082
Acquisitions and purchase accounting adjustments	2,420	38,209
Translation impact	2,296	(260)
Goodwill, Ending Balance	474,747	470,031
Industrial Solutions
Goodwill [Roll Forward]
Goodwill, Beginning Balance	773,638	774,795
Acquisitions and purchase accounting adjustments	0	0
Translation impact	3,553	(1,157)
Goodwill, Ending Balance	$ 777,191	$ 773,638

Intangible Assets - Changes i_2

Intangible Assets - Changes in Carrying Amount of Trademarks (Details) - Trademarks - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Indefinite-lived Intangible Assets [Roll Forward]
Trademarks, Beginning Balance	$ 40,106	$ 40,270
Translation impact		(164)
Reclassify to definite-lived	(9,043)
Trademarks, Ending Balance	31,063	40,106
Enterprise Solutions
Indefinite-lived Intangible Assets [Roll Forward]
Trademarks, Beginning Balance	27,000	27,000
Translation impact		0
Reclassify to definite-lived	0
Trademarks, Ending Balance	27,000	27,000
Industrial Solutions
Indefinite-lived Intangible Assets [Roll Forward]
Trademarks, Beginning Balance	13,106	13,270
Translation impact		(164)
Reclassify to definite-lived	(9,043)
Trademarks, Ending Balance	$ 4,063	$ 13,106

Intangible Assets - Additional

Intangible Assets - Additional Information (Details)	12 Months Ended
	Dec. 31, 2020USD ($)Reporting_Unit	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Finite And Indefinite Intangible Assets [Line Items]
Number of reporting units used in quantitative assessment | Reporting_Unit	10
Goodwill impairment loss	$ 0	$ 0	$ 0
Impairment of indefinite lived intangible assets	0	0	0
Amortization expense in income from continuing operations	66,200,000	74,600,000	75,100,000
Amortization of intangibles	64,395,000	74,609,000	75,140,000
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Estimated amortization expense in 2020	35,600,000
Estimated amortization expense in 2021	32,900,000
Estimated amortization expense in 2022	31,200,000
Estimated amortization expense in 2023	29,000,000
Estimated amortization expense in 2024	24,700,000
Finite-Lived Intangible Assets, Accumulated Amortization	(556,379,000)	(490,736,000)
Trademark, net carrying amount	$ 256,008,000	298,599,000
Customer relationships
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Weighted-average amortization period	18 years 2 months 12 days
Finite-Lived Intangible Assets, Accumulated Amortization	$ (128,796,000)	(110,732,000)
Trademark, net carrying amount	166,586,000	186,863,000
Trademarks
Finite And Indefinite Intangible Assets [Line Items]
Impairment of indefinite lived intangible assets	$ 0	0	0
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Weighted-average amortization period	8 years 3 months 18 days
Finite-Lived Intangible Assets, Accumulated Amortization	$ (36,539,000)	(30,213,000)
Trademark, net carrying amount	29,322,000	26,180,000
Trademarks | Intangible Assets, Amortization Period
Finite And Indefinite Intangible Assets [Line Items]
Amortization of intangibles	1,800,000
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Trademark, net carrying amount	$ 7,800,000
Developed technologies
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Weighted-average amortization period	6 years 9 months 18 days
Finite-Lived Intangible Assets, Accumulated Amortization	$ (369,849,000)	(331,696,000)
Trademark, net carrying amount	$ 58,338,000	81,614,000
In-process research and development
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Weighted-average amortization period	5 years
Finite-Lived Intangible Assets, Accumulated Amortization	$ (9,774,000)	(7,160,000)
Trademark, net carrying amount	1,762,000	3,542,000
Grass Valley
Finite And Indefinite Intangible Assets [Line Items]
Impairment of the disposal group	113,000,000	521,400,000
Discontinued Operations, Held-for-sale
Finite And Indefinite Intangible Assets [Line Items]
Impairment of the disposal group		179,300,000
Translation exchange rates		180,400,000
Discontinued Operations, Held-for-sale | Customer relationships
Finite And Indefinite Intangible Assets [Line Items]
Impairment of intangible assets		14,400,000
Discontinued Operations, Held-for-sale | Trademarks
Finite And Indefinite Intangible Assets [Line Items]
Impairment of intangible assets		1,600,000
Discontinued Operations, Held-for-sale | Grass Valley
Finite And Indefinite Intangible Assets [Line Items]
Impairment of the disposal group	113,007,000	521,441,000	$ 0
Goodwill impairment loss		$ 326,100,000
Impairment of the disposal group	179,300,000
Translation exchange rates	180,400,000
Discontinued Operations, Held-for-sale | Grass Valley | Customer relationships
Finite And Indefinite Intangible Assets [Line Items]
Impairment of intangible assets	14,400,000
Discontinued Operations, Held-for-sale | Grass Valley | Trademarks
Finite And Indefinite Intangible Assets [Line Items]
Impairment of intangible assets	$ 1,600,000

Accrued Liabilities - Carrying

Accrued Liabilities - Carrying Value of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued Liabilities and Other Liabilities [Abstract]
Wages, severance and related taxes	$ 65,892	$ 58,953
Current deferred revenue	53,371	54,255
Accrued rebates	32,192	37,170
Accrued interest	20,610	18,781
Employee benefits	27,707	17,791
Lease liabilities	14,840	14,072
Other (individual items less than 5% of total current liabilities)	62,029	82,777
Accrued liabilities	$ 276,641	$ 283,799

Accrued Liabilities - Additiona

Accrued Liabilities - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 29, 2020	Dec. 31, 2019
Accrued Liabilities and Other Liabilities [Abstract]
Payment for contingent consideration liability		$ 31.4
Business combination, earnout liability	$ 29.3
Payment for contingent consideration liability, operating activities	$ 2.1

Severance, Restructuring, and_3

Severance, Restructuring, and Acquisition Integration Activities Severance, Restructuring, and Acquisition Integration Activities - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2021	Sep. 27, 2020	Jun. 28, 2020	Mar. 29, 2020
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs	$ 12,258	$ 26,544	$ 22,625
Restructuring and integration cost payable period	60 days
Other restructuring costs	$ 9,207	5,790	21,837
Severance	3,051	20,754	788
Cost of sales
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs	704	3,425	17,962
Selling, general and administrative expenses
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs	11,554	23,119	4,546
Research and development expenses
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs	0	0	117
Industrial Manufacturing Footprint Program
Restructuring Cost and Reserve [Line Items]
Other restructuring costs			66,100
Severance			$ 17,700
FutureLink, Opterna, and SPC Integration Program
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs	4,900	6,100
Cost Reduction Plan
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs	4,000	19,600
Restructuring Reserve	7,085	$ 19,575			$ 8,093	$ 11,698	$ 13,385
Restructuring and related cost, expected to be realized	40,000
Cost Reduction Plan | Selling, general and administrative expenses
Restructuring Cost and Reserve [Line Items]
Expected cost	$ 60,000
Scenario, Forecast | FutureLink, Opterna, and SPC Integration Program
Restructuring Cost and Reserve [Line Items]
Expected restructuring cost remaining				$ 1,000
Scenario, Forecast | Cost Reduction Plan
Restructuring Cost and Reserve [Line Items]
Expected restructuring cost remaining				$ 8,000

Severance, Restructuring, and_4

Severance, Restructuring, and Acquisition Integration Activities Severance, Restructuring, and Acquisition Integration Activities - Severance, Restructuring and Integration Costs by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Severance	$ 3,051	$ 20,754	$ 788
Other Restructuring and Integration Costs	9,207	5,790	21,837
Total Costs	12,258	26,544	22,625
FutureLink, Opterna, and SPC Integration Program
Restructuring Cost and Reserve [Line Items]
Total Costs	4,900	6,100
Enterprise Solutions
Restructuring Cost and Reserve [Line Items]
Severance	1,345	5,018	548
Other Restructuring and Integration Costs	6,374	5,790	14,315
Total Costs	7,719	10,808	14,863
Industrial Solutions
Restructuring Cost and Reserve [Line Items]
Severance	1,706	15,736	240
Other Restructuring and Integration Costs	2,833	0	7,522
Total Costs	$ 4,539	$ 15,736	$ 7,762

Severance, Restructuring, and_5

Severance, Restructuring, and Acquisition Integration Activities - Costs of Various Programs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs	$ 12,258	$ 26,544	$ 22,625
Cost of sales
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs	704	3,425	17,962
Selling, general and administrative expenses
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs	11,554	23,119	4,546
Research and development expenses
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs	$ 0	$ 0	$ 117

Severance, Restructuring, and_6

Severance, Restructuring, and Acquisition Integration Activities - Accrued Severance (Details) - Cost Reduction Plan - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Sep. 27, 2020	Jun. 28, 2020	Mar. 29, 2020
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance	$ 8,093	$ 11,698	$ 13,385	$ 19,575
New charges	992	2,060	4,660	2,529
Cash payments	(1,823)	(3,968)	(4,795)	(4,483)
Foreign currency translation	(95)	(156)	(132)	(89)
Other adjustments	(82)	(1,541)	(1,420)	(4,147)
Restructuring Reserve, Ending Balance	$ 7,085	$ 8,093	$ 11,698	$ 13,385

Long-Term Debt and Other Borr_3

Long-Term Debt and Other Borrowing Arrangements - Carrying Values of Long-Term Debt and Other Borrowing Arrangements (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2018	Sep. 30, 2017	Jul. 31, 2017	Oct. 31, 2016
Debt Instrument [Line Items]
Total senior subordinated notes	$ 1,590,810	$ 1,459,380
Less unamortized debt issuance costs	(17,084)	(19,896)
Long-term debt	1,573,726	1,439,484
Revolving credit agreement due 2022
Debt Instrument [Line Items]
Revolving credit agreement due 2022	0	0
3.875% Senior Subordinated Notes Due 2028
Debt Instrument [Line Items]
Total senior subordinated notes	428,295	392,910
3.375% Senior Subordinated Notes Due 2027
Debt Instrument [Line Items]
Total senior subordinated notes	550,665	505,170
4.125% Senior Subordinated Notes Due 2026
Debt Instrument [Line Items]
Total senior subordinated notes	244,740	224,520
2.875% Senior Subordinated Notes Due 2025
Debt Instrument [Line Items]
Total senior subordinated notes	$ 367,110	$ 336,780
Senior Subordinated Notes | 3.875% Senior Subordinated Notes Due 2028
Debt Instrument [Line Items]
Senior subordinated notes interest rate			3.875%
Senior Subordinated Notes | 3.375% Senior Subordinated Notes Due 2027
Debt Instrument [Line Items]
Senior subordinated notes interest rate					3.375%
Senior Subordinated Notes | 4.125% Senior Subordinated Notes Due 2026
Debt Instrument [Line Items]
Senior subordinated notes interest rate						4.125%
Senior Subordinated Notes | 2.875% Senior Subordinated Notes Due 2025
Debt Instrument [Line Items]
Senior subordinated notes interest rate				2.875%

Long-Term Debt and Other Borr_4

Long-Term Debt and Other Borrowing Arrangements - Additional Information (Details)	1 Months Ended					12 Months Ended
	Apr. 30, 2020USD ($)	Apr. 30, 2018USD ($)	Apr. 30, 2018EUR (€)	Mar. 31, 2018USD ($)	Mar. 31, 2018EUR (€)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Mar. 31, 2018EUR (€)	Sep. 30, 2017EUR (€)	Jul. 31, 2017EUR (€)	Oct. 31, 2016EUR (€)
Debt Instrument [Line Items]
Long term debt borrowings	$ 190,000,000
Loss on debt extinguishment						$ 0	$ 0	$ 22,990,000
Debt issuance costs paid						0	0	7,609,000
Senior subordinated notes						1,590,810,000	1,459,380,000
Senior Subordinated Notes
Debt Instrument [Line Items]
Fair value of debt instrument						1,633,700,000	1,532,700,000
Revolving credit agreement due 2022
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity								$ 400,000,000
Commitment fee percentage								0.25%
Fixed charge coverage, minimum threshold (as a percent)								90.00%
Revolving credit agreement due 2022, execution fees								$ 2,300,000
Revolving credit agreement due 2022, borrowings outstanding						0	0
Revolving credit agreement due 2022, available borrowing capacity						230,200,000
Revolving credit agreement due 2022 | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate (as a percent)								1.25%
Revolving credit agreement due 2022 | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate (as a percent)								1.75%
3.875% Senior Subordinated Notes Due 2028
Debt Instrument [Line Items]
Senior subordinated notes						428,295,000	392,910,000
3.875% Senior Subordinated Notes Due 2028 | Senior Subordinated Notes
Debt Instrument [Line Items]
Aggregate principal amount outstanding of senior subordinated notes				$ 431,300,000					€ 350,000,000
Senior subordinated notes interest rate				3.875%					3.875%
Debt issuance costs paid						7,500,000
3.375% Senior Subordinated Notes Due 2027
Debt Instrument [Line Items]
Senior subordinated notes						550,665,000	505,170,000
3.375% Senior Subordinated Notes Due 2027 | Senior Subordinated Notes
Debt Instrument [Line Items]
Aggregate principal amount outstanding of senior subordinated notes | €											€ 450,000,000
Senior subordinated notes interest rate											3.375%
4.125% Senior Subordinated Notes Due 2026
Debt Instrument [Line Items]
Senior subordinated notes						244,740,000	224,520,000
4.125% Senior Subordinated Notes Due 2026 | Senior Subordinated Notes
Debt Instrument [Line Items]
Aggregate principal amount outstanding of senior subordinated notes | €												€ 200,000,000
Senior subordinated notes interest rate												4.125%
2.875% Senior Subordinated Notes Due 2025
Debt Instrument [Line Items]
Senior subordinated notes						$ 367,110,000	$ 336,780,000
2.875% Senior Subordinated Notes Due 2025 | Senior Subordinated Notes
Debt Instrument [Line Items]
Aggregate principal amount outstanding of senior subordinated notes | €										€ 300,000,000
Senior subordinated notes interest rate										2.875%
5.25% Senior Subordinated Notes Due 2024 | Senior Subordinated Notes
Debt Instrument [Line Items]
Loss on debt extinguishment		$ 800,000		$ 13,800,000
Aggregate principal amount outstanding of senior subordinated notes				$ 200,000,000
Senior subordinated notes interest rate				5.25%					5.25%
Repurchase amount				$ 188,700,000
Repayments of debt		11,900,000		199,800,000
5.5% Senior Subordinated Notes Due 2023 | Senior Subordinated Notes
Debt Instrument [Line Items]
Loss on debt extinguishment		2,200,000		$ 6,200,000
Aggregate principal amount outstanding of senior subordinated notes | €									€ 200,000,000
Senior subordinated notes interest rate				5.50%					5.50%
Repurchase amount | €									€ 143,100,000
Repayments of debt		$ 71,600,000	€ 58,500,000	$ 182,100,000	€ 147,800,000

Long-Term Debt and Other Borr_5

Long-Term Debt and Other Borrowing Arrangements - Schedule of Senior Subordinated Notes (Details)	12 Months Ended
	Dec. 31, 2020
2021 | Senior Subordinated Notes Due 2025
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	100.719%
2021 | Senior Subordinated Notes Due 2026
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	102.063%
2022 | Senior Subordinated Notes Due 2026
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	101.375%
2022 | Senior Subordinated Notes Due 2027
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	101.688%
2023 | Senior Subordinated Notes Due 2026
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	100.688%
2023 | Senior Subordinated Notes Due 2027
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	101.125%
2023 | Senior Subordinated Notes Due 2028
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	101.938%
2024 | Senior Subordinated Notes Due 2027
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	100.563%
2024 | Senior Subordinated Notes Due 2028
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	101.292%
2025 | Senior Subordinated Notes Due 2028
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	100.646%
2022 And Thereafter | Senior Subordinated Notes Due 2025
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	100.00%
2024 and Thereafter | Senior Subordinated Notes Due 2026
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	100.00%
2025 and Thereafter | Senior Subordinated Notes Due 2027
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	100.00%
2026 and Thereafter | Senior Subordinated Notes Due 2028
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	100.00%
Two Thousand And Twenty Twenty | Senior Subordinated Notes Due 2025
Debt Instrument [Line Items]
Redemption price as a percentage of the face amount of the notes	101.438%

Long-Term Debt and Other Borr_6

Long-Term Debt and Other Borrowing Arrangements - Maturities on Outstanding Long-Term Debt and Other Borrowings (Details) $ in Thousands	Dec. 31, 2020USD ($)
Debt Disclosure [Abstract]
2020	$ 0
2021	0
2022	0
2023	0
2024	367,110
Thereafter	1,223,700
Total gross debt and other borrowing arrangements	$ 1,590,810

Net Investment Hedge Net Invest

Net Investment Hedge Net Investment Hedge (Details) $ in Thousands, € in Millions	12 Months Ended
	Dec. 31, 2020USD ($)	Dec. 31, 2020EUR (€)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative translation adjustment | $	$ (112,562)		$ 24,121	$ 27,802
Senior subordinated debt, dedesignated | €		€ 532.2
Senior Subordinated Notes
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Senior subordinated debt, hedged | €		€ 767.8
Cumulative translation adjustment | $	$ (56,200)		$ 26,600	$ 87,500

Income Taxes - Components of In

Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income (loss) before taxes:
United States operations	$ (117,819)	$ 42,833	$ 115,500
Foreign operations	183,946	109,577	114,580
Income from continuing operations before taxes	66,127	152,410	230,080
Currently payable
United States federal	273	21,893	31,730
United States state and local	91	3,090	3,912
Foreign	11,511	13,859	16,968
Income tax expense (benefit)	11,875	38,842	52,610
Deferred
United States federal	(1,754)	7,567	7,220
United States state and local	(2,310)	(1,205)	(31)
Foreign	3,913	(2,685)	3,137
Deferred Income tax expense (benefit)	(151)	3,677	10,326
Income tax expense	$ 11,724	$ 42,519	$ 62,936

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate Reconciliation from Continuing Operations (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Effective income tax rate reconciliation from continuing operations:
United States federal statutory rate	21.00%	21.00%	21.00%
State and local income taxes	(2.60%)	1.20%	1.50%
Impact of change in tax contingencies	2.30%	0.00%	(0.70%)
Foreign income tax rate differences	(38.20%)	(8.60%)	(1.00%)
Impact of change in deferred tax asset valuation allowance	3.10%	9.20%	0.30%
Domestic permanent differences and tax credits	33.90%	5.10%	1.90%
Impact of tax reform	0	0	0.044
Impact of CARES act	(0.018)	0	0
Effective income tax rate reconciliation from continuing operations	17.70%	27.90%	27.40%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	Jul. 02, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2040	Dec. 31, 2024	Mar. 29, 2020
Income Taxes [Line Items]
Income Tax Expense (Benefit)		$ (11,724)	$ (42,519)	$ (62,936)
Foreign tax rate differences benefit in income tax		25,300	13,100	2,400
Income tax expense reduction due to tax holiday		4,000	3,900	3,000
Net tax credit carryforwards		57,100
Net operating loss carryforwards		205,352					$ 1,200
Operating loss carryforwards that will be used in expiration periods		137,100
Net tax credit carryforwards that will expire		57,109
Net tax credit carry forwards with indefinite carry forward period		5,400
Net tax credit carryforwards that expected to be utilized prior to expiry		17,300
Net decrease in reserve for uncertain tax positions		1,800
Balance at end of the year of unrecognized tax benefits		8,573	6,779	6,591
Estimate the range of reasonably possible changes to unrecognized tax positions		1,700
Accrued interest expense (income) and penalties of unrecognized tax benefits		200	0
Domestic Tax Authority [Member]
Income Taxes [Line Items]
Net tax credit carryforwards		22,400
Capital Loss Carryforward
Income Taxes [Line Items]
Net operating loss carryforwards		100,500
Capital Loss Carryforward | Grass Valley
Income Taxes [Line Items]
Valuation allowance, deferred tax asset, increase (decrease), amount	$ 23,800
Discontinued Operations
Income Taxes [Line Items]
Income Tax Expense (Benefit)		(22,600)	$ (27,200)	$ 3,300
Scenario, Forecast
Income Taxes [Line Items]
Net tax credit carryforwards that will expire					$ 49,600	$ 2,100
Net Operating Loss Carry Forward Indefinite Period
Income Taxes [Line Items]
Net operating loss carryforwards		58,000
Net Operating Loss Carry Forwards Expires In 2020
Income Taxes [Line Items]
Net operating loss carryforwards		900
Net Operating Loss Carry Forwards Expires Between 2021 And 2024
Income Taxes [Line Items]
Net operating loss carryforwards		19,700
Net Operating Loss Carry Forwards Expires Between 2025 And 2040
Income Taxes [Line Items]
Net operating loss carryforwards		$ 126,800

Income Taxes - Components of De

Income Taxes - Components of Deferred Income Tax Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred income tax liabilities:
Plant, equipment, and intangibles	$ (92,271)	$ (96,254)
Plant, equipment, and intangibles	(17,610)	(16,906)
Total Deferred Tax Liabilities, Gross	(109,881)	(113,160)
Deferred income tax assets:
Postretirement, pensions, and stock compensation	35,394	28,169
Reserves and accruals	24,388	15,395
Net operating loss, capital loss, and tax credit carryforwards	107,028	76,456
Lease liability	18,515	17,882
Valuation allowances	(84,308)	(48,251)
Deferred tax assets	101,017	89,651
Net deferred income tax asset	$ (8,864)	$ (23,509)

Income Taxes - Summary of Net O

Income Taxes - Summary of Net Operating Loss Carryforwards (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Mar. 29, 2020
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	$ 205,352	$ 1,200
Australia
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	10,546
Germany
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	15,852
Japan
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	653
Luxembourg
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	163
Netherlands
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	6,578
Other
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	20,723
United Kingdom
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	10,720
United States - Federal and various states
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforwards	$ 140,117

Income Taxes - Summary of Tax C

Income Taxes - Summary of Tax Credit Carryforwards (Details) $ in Thousands	Dec. 31, 2020USD ($)
Tax Credit Carryforward [Line Items]
Tax Credit Carryforwards	$ 57,109
United States
Tax Credit Carryforward [Line Items]
Tax Credit Carryforwards	56,617
Canada
Tax Credit Carryforward [Line Items]
Tax Credit Carryforwards	$ 492

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 6,779	$ 6,591
Additions based on tax positions related to the current year	548	488
Additions for tax positions of prior years	1,574	0
Reductions for tax positions of prior years - Settlement	(328)	(300)
Balance at end of year	$ 8,573	$ 6,779

Pension and Other Postretirem_3

Pension and Other Postretirement Benefits - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined contribution expense	$ 10,000	$ 12,100	$ 11,800
Accumulated benefit obligation	$ 518,400	456,900
Target asset allocation for the investment of the assets in fixed income securities minimum	50.00%
Target asset allocation for the investment of the assets in fixed income securities maximum	90.00%
Target asset allocation for the investment of the assets in equity securities minimum	10.00%
Target asset allocation for the investment of the assets in equity securities maximum	50.00%
Minimum
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation for the investment of the assets in fixed income securities	30.00%
Target asset allocation for the investment of the assets in equity securities	50.00%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation for the investment of the assets in fixed income securities	50.00%
Target asset allocation for the investment of the assets in equity securities	70.00%
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension plans with projected benefit obligation in excess of plan assets, projected benefit obligation	$ 297,800	293,700
Pension plans with projected benefit obligation in excess of plan assets, accumulated benefit obligation	459,200	400,400
Pension plans with projected benefit obligation in excess of plan assets, fair value of plan assets	463,200	404,900
Settlement loss (gain)	3,153		$ 1,300
Anticipated pension and other postretirement plans contributions, next fiscal year	11,400
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Other postretirement plans with accumulated benefit obligation in excess of plan assets, accumulated benefit obligation	59,200	29,500
Other postretirement plans with accumulated benefit obligation in excess of plan assets, fair value of plan assets	64,000	$ 0
Settlement loss (gain)	0
Anticipated pension and other postretirement plans contributions, next fiscal year	$ 1,500

Pension and Other Postretirem_4

Pension and Other Postretirement Benefits - Change in Benefit Obligation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Change in benefit obligation:
Benefit obligation, beginning of year	$ (461,352)	$ (412,880)
Service cost	(3,930)	(3,668)	$ (4,579)
Interest cost	(9,729)	(12,261)	(11,480)
Participant contributions	(73)	(86)
Actuarial loss	(42,284)	(39,329)
Divestitures and acquisitions	(910)	0
Settlements	26,970	49
Curtailments	236
Plan amendments	(226)	0
Foreign currency exchange rate changes	(15,345)	(9,890)
Benefits paid	13,718	16,713
Benefit obligation, end of year	(492,925)	(461,352)	(412,880)
Other Benefits
Change in benefit obligation:
Benefit obligation, beginning of year	(29,470)	(26,143)
Service cost	(33)	(35)	(47)
Interest cost	(809)	(960)	(945)
Participant contributions	(5)	(4)
Actuarial loss	(110)	(2,374)
Divestitures and acquisitions	0	0
Settlements	0	0
Curtailments	0
Plan amendments	0	0
Foreign currency exchange rate changes	(427)	(1,260)
Benefits paid	1,356	1,306
Benefit obligation, end of year	$ (29,498)	$ (29,470)	$ (26,143)

Pension and Other Postretirem_5

Pension and Other Postretirement Benefits - Change in Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Change in plan assets:
Fair value of plan assets, beginning of year	$ 355,726
Fair value of plan assets, end of year	361,802	$ 355,726
Pension Benefits
Change in plan assets:
Fair value of plan assets, beginning of year	355,726	311,509
Actual return on plan assets	32,470	45,896
Employer contributions	6,393	5,673
Plan participant contributions	73	86
Settlements	(26,945)	0
Foreign currency exchange rate changes	7,803	9,275
Benefits paid	(13,718)	(16,713)
Fair value of plan assets, end of year	361,802	355,726
Other Benefits
Change in plan assets:
Fair value of plan assets, beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	1,351	1,302
Plan participant contributions	5	4
Settlements	0	0
Foreign currency exchange rate changes	0	0
Benefits paid	(1,356)	(1,306)
Fair value of plan assets, end of year	$ 0	$ 0

Pension and Other Postretirem_6

Pension and Other Postretirement Benefits - Amounts Recognized in Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Amounts recognized in the balance sheets:
Accrued benefit liability, noncurrent	$ (160,400)	$ (136,227)
Pension Benefits
Pension And Other Employee Benefit Plans [Line Items]
Funded status, end of year	(131,123)	(105,626)
Amounts recognized in the balance sheets:
Prepaid benefit cost	4,780	5,542
Accrued benefit liability, current	(3,558)	(3,000)
Accrued benefit liability, noncurrent	(132,345)	(108,168)
Net funded status	(131,123)	(105,626)
Other Benefits
Pension And Other Employee Benefit Plans [Line Items]
Funded status, end of year	(29,498)	(29,470)
Amounts recognized in the balance sheets:
Prepaid benefit cost	0	0
Accrued benefit liability, current	(1,443)	(1,411)
Accrued benefit liability, noncurrent	(28,055)	(28,059)
Net funded status	$ (29,498)	$ (29,470)

Pension and Other Postretirem_7

Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Components of net periodic benefit cost:
Service cost	$ 3,930	$ 3,668	$ 4,579
Interest cost	9,729	12,261	11,480
Expected return on plan assets	(16,357)	(15,699)	(16,389)
Amortization of prior service cost (credit)	190	169	(42)
Settlement loss (gain)	3,153	(7)	1,342
Net loss (gain) recognition	2,930	1,432	2,775
Net periodic benefit cost	3,575	1,824	3,745
Other Benefits
Components of net periodic benefit cost:
Service cost	33	35	47
Interest cost	809	960	945
Expected return on plan assets	0	0	0
Amortization of prior service cost (credit)	0	0	0
Settlement loss (gain)	0	0	0
Net loss (gain) recognition	(59)	(133)	(12)
Net periodic benefit cost	$ 783	$ 862	$ 980

Pension and Other Postretirem_8

Pension and Other Postretirement Benefits - Assumptions Used in Determining Benefit Obligations and Net Periodic Benefit Cost Amounts (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits
Weighted average assumptions for benefit obligations at year end:
Discount rate	1.50%	2.20%
Salary increase	3.30%	3.50%
Cash balance interest credit rate	4.60%	4.00%
Weighted average assumptions for net periodic cost for the year:
Discount rate	2.20%	3.10%
Salary increase	3.50%	3.60%
Cash balance interest credit rate	4.00%	4.70%
Expected return on assets	4.90%	5.00%
Other Benefits
Weighted average assumptions for benefit obligations at year end:
Discount rate	2.50%	2.90%
Weighted average assumptions for net periodic cost for the year:
Discount rate	2.90%	3.70%
Assumed health care cost trend rates:
Health care cost trend rate assumed for next year	5.50%	5.60%
Rate that the cost trend rate gradually declines to	5.00%	5.00%

Pension and Other Postretirem_9

Pension and Other Postretirement Benefits - Fair Values of Pension Plan Assets by Asset Category (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	$ 361,802	$ 355,726
U.S. equities fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	86,059	131,563
Non-U.S. equities fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	61,630	54,496
Government bond fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	98,418	74,219
Corporate bond fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	82,434	40,940
Fixed income fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	7,320	35,895
Other investments
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	17,367	9,462
Cash & equivalents
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	8,574	9,151
Quoted Prices in Active Markets for Identical Assets (Level 1)
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	11,844	8,909
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. equities fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	3,012	2,793
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-U.S. equities fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	5,602	5,949
Quoted Prices in Active Markets for Identical Assets (Level 1) | Government bond fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bond fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed income fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other investments
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash & equivalents
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	3,230	167
Significant Observable Inputs (Level 2)
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	12,922	44,300
Significant Observable Inputs (Level 2) | U.S. equities fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	0	0
Significant Observable Inputs (Level 2) | Non-U.S. equities fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	0	0
Significant Observable Inputs (Level 2) | Government bond fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	772	745
Significant Observable Inputs (Level 2) | Corporate bond fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	12,150	9,854
Significant Observable Inputs (Level 2) | Fixed income fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	0	33,701
Significant Observable Inputs (Level 2) | Other investments
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	0	0
Significant Observable Inputs (Level 2) | Cash & equivalents
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	0	0
Fair Value Measured at Net Asset Value Per Share
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	337,036	302,517
Fair Value Measured at Net Asset Value Per Share | U.S. equities fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	83,047	128,770
Fair Value Measured at Net Asset Value Per Share | Non-U.S. equities fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	56,028	48,547
Fair Value Measured at Net Asset Value Per Share | Government bond fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	97,646	73,474
Fair Value Measured at Net Asset Value Per Share | Corporate bond fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	70,284	31,086
Fair Value Measured at Net Asset Value Per Share | Fixed income fund
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	7,320	2,194
Fair Value Measured at Net Asset Value Per Share | Other investments
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	17,367	9,462
Fair Value Measured at Net Asset Value Per Share | Cash & equivalents
Pension And Other Employee Benefit Plans [Line Items]
Fair values of pension plan assets by asset category	$ 5,344	$ 8,984

Pension and Other Postretire_10

Pension and Other Postretirement Benefits - Benefits Expected to be Paid in Subsequent Years from Our Pension and Other Postretirement as Well as Medicare Subsidy Receipts (Details) $ in Thousands	Dec. 31, 2020USD ($)
Pension Benefits
Pension And Other Employee Benefit Plans [Line Items]
2021	$ 19,497
2022	19,044
2023	20,320
2024	21,247
2025	19,417
2026-2030	99,881
Total	199,406
Other Benefits
Pension And Other Employee Benefit Plans [Line Items]
2021	1,460
2022	1,457
2023	1,458
2024	1,463
2025	1,466
2026-2030	7,413
Total	$ 14,717

Pension and Other Postretire_11

Pension and Other Postretirement Benefits - Summary of Accumulated Other Comprehensive Loss That Have Not Been Recognized as Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	$ 80,671	$ 56,746
Net prior service cost	2,798	2,661
Total	83,469
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	(436)	(600)
Net prior service cost	0	$ 0
Total	$ (436)

Pension and Other Postretire_12

Pension and Other Postretirement Benefits - Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Net actuarial loss (gain), beginning of year	$ 56,746
Amortization of actuarial gain (loss)	(2,930)
Actuarial loss	42,048
Asset gain	(16,113)
Settlement loss recognized	(3,153)		$ (1,300)
Divestitures and acquisitions	335
Currency impact	3,738
Net actuarial loss (gain), end of year	80,671	$ 56,746
Prior service cost, beginning of year	2,661
Amortization of prior service cost	(190)	(169)	42
Prior service cost occurring during the year	226
Currency impact	101
Prior service cost, end of year	2,798	2,661
Other Benefits
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Net actuarial loss (gain), beginning of year	(600)
Amortization of actuarial gain (loss)	59
Actuarial loss	110
Asset gain	0
Settlement loss recognized	0
Divestitures and acquisitions	0
Currency impact	(5)
Net actuarial loss (gain), end of year	(436)	(600)
Prior service cost, beginning of year	0
Amortization of prior service cost	0	0	$ 0
Prior service cost occurring during the year	0
Currency impact	0
Prior service cost, end of year	$ 0	$ 0

Comprehensive Income and Accu_3

Comprehensive Income and Accumulated Other Comprehensive Income (Loss) - Components of Other Comprehensive Income (Loss), Net of Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 965,819	$ 1,387,588
Other comprehensive gain (loss) attributable to Belden before reclassifications	(143,901)	10,376
Amounts reclassified from accumulated other comprehensive income	15,468	1,113
Net current period other comprehensive gain (loss) attributable to Belden		11,489
Ending balance	757,051	965,819
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(63,418)	(74,907)
Ending balance	(191,851)	(63,418)
Foreign Currency Translation Component
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(18,225)	(41,882)
Other comprehensive gain (loss) attributable to Belden before reclassifications	(123,101)	23,657
Amounts reclassified from accumulated other comprehensive income	10,145	0
Net current period other comprehensive gain (loss) attributable to Belden	(112,956)	23,657
Ending balance	(131,181)	(18,225)
Pension and Other Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(45,193)	(33,025)
Other comprehensive gain (loss) attributable to Belden before reclassifications	(20,800)	(13,281)
Amounts reclassified from accumulated other comprehensive income	5,323	1,113
Net current period other comprehensive gain (loss) attributable to Belden	(15,477)	(12,168)
Ending balance	$ (60,670)	$ (45,193)

Comprehensive Income and Accu_4

Comprehensive Income and Accumulated Other Comprehensive Income (Loss) - Summary of Effects of Reclassifications from Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Amortization of pension and other postretirement benefit plan items:
Total before tax	$ 66,127	$ 152,410	$ 230,080
Tax benefit	11,724	42,519	62,936
Total net of tax	(55,162)	$ (377,015)	$ 160,894
Settlement loss
Amortization of pension and other postretirement benefit plan items:
Other nonoperating expense (income)	3,153
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Actuarial losses
Amortization of pension and other postretirement benefit plan items:
Other nonoperating expense (income)	2,871
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Actuarial losses | Grass Valley
Amortization of pension and other postretirement benefit plan items:
Other nonoperating expense (income)	771
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Prior service cost
Amortization of pension and other postretirement benefit plan items:
Other nonoperating expense (income)	190
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Pension and Other Postretirement Benefit Plans
Amortization of pension and other postretirement benefit plan items:
Total before tax	6,985
Tax benefit	(1,662)
Total net of tax	5,323
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Foreign Currency Translation Component | Grass Valley
Amortization of pension and other postretirement benefit plan items:
Other nonoperating expense (income)	$ (10,100)

Share-Based Compensation - Inco

Share-Based Compensation - Income Tax Benefit Recognized for our Share-Based Compensation Arrangements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement [Abstract]
Total share-based compensation cost	$ 19,171	$ 16,802	$ 17,143
Income tax benefit	$ 4,563	$ 3,999	$ 4,080

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to all nonvested awards	$ 25
Unrecognized compensation cost is expected to be recognized over a weighted-average period	1 year 7 months 6 days
Share-based compensation, modification of terms, incremental compensation cost	$ 1.4
Share-based compensation, modification of terms, expected incremental compensation cost	$ 4.4
SARs and Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
SAR's and stock options expiration period	10 years
Restricted Shares and Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Restricted Shares and Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	5 years

Share-Based Compensation - Fair

Share-Based Compensation - Fair Values for SARs and Stock Options Estimated on Grant Date Using Black-Scholes-Merton Option-Pricing Formula Which Incorporates Assumptions (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement [Abstract]
Weighted-average fair value of SARs and options granted (in usd per share)	$ 18.29	$ 22.31	$ 25.19
Total intrinsic value of SARs converted and options exercised	$ 545	$ 354	$ 2,263
Tax benefit (expense) related to share-based compensation	$ (560)	$ (101)	$ 113
Weighted-average fair value of restricted stock shares and units granted (in usd per share)	$ 41.75	$ 64.61	$ 72.54
Total fair value of restricted stock shares and units vested	$ 6,600	$ 10,325	$ 5,740
Expected volatility	37.55%	35.05%	33.16%
Expected term (in years)	5 years 8 months 12 days	5 years 8 months 12 days	5 years 7 months 6 days
Risk-free rate	1.44%	2.56%	2.70%
Dividend yield	0.39%	0.32%	0.27%

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Share Based Compensation Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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, Weighted Average Grant Date Fair Value [Abstract]
Granted, Weighted-Average Grant-Date Fair Value (in dollars per share)	$ 41.75	$ 64.61	$ 72.54
SARs and Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at Beginning, Number (in shares)	1,367
Granted, Number (in shares)	149
Exercised or converted, Number (in shares)	(38)
Forfeited or expired, Number (in shares)	(167)
Outstanding at Ending, Number (in shares)	1,311	1,367
Vested or expected to vest at End, Number (in shares)	1,266
Exercisable or convertible at End, Number (in shares)	1,021
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding at Beginning, Weighted-Average Exercise Price (in dollars per share)	$ 65.04
Granted, Weighted-Average Exercise Price (in dollars per share)	51.14
Exercised or converted, Weighted-Average Exercise Price (in dollars per share)	38.24
Forfeited or expired, Weighted-Average Exercise Price (in dollars per share)	66.42
Outstanding at End, Weighted-Average Exercise Price (in dollars per share)	64.06	$ 65.04
Vested or expected to vest at End, Weighted-Average Exercise Price	64.09
Exercisable or convertible at End, Weighted-Average Exercise Price	$ 62.62
Outstanding at End, Weighted-Average Remaining Contractual Term	5 years 8 months 12 days
Vested or expected to vest at End, Weighted-Average Remaining Contractual Term	5 years 8 months 12 days
Exercisable or convertible at End, Weighted-Average Remaining Contractual Term	5 years 6 months
Outstanding at End, Aggregate Intrinsic Value	$ (29,054)
Vested or expected to vest at End, Aggregate Intrinsic Value	(28,096)
Exercisable or convertible at End, Aggregate Intrinsic Value	$ (24,060)
Restricted Shares and Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at Beginning, Number (in shares)	737
Granted, Number (in shares)	565
Exercised or converted, Number (in shares)	(102)
Forfeited or expired, Number (in shares)	(247)
Outstanding at End, Number (in shares)	953	737
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding at Beginning, Weighted-Average Grant-Date Fair Value (in dollars per share)	$ 68.31
Granted, Weighted-Average Grant-Date Fair Value (in dollars per share)	41.75
Exercised or converted, Weighted-Average Grant-Date Fair Value (in dollars per share)	64.56
Forfeited or expired, Weighted-Average Grant-Date Fair Value (in dollars per share)	75.07
Outstanding at End, Weighted-Average Grant-Date Fair Value (in dollars per share)	$ 52.50	$ 68.31

Preferred Stock (Details)

Preferred Stock (Details) $ / shares in Units, $ in Thousands	Jul. 15, 2019shares	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2016USD ($)$ / sharesshares	Jul. 26, 2016
Class of Stock [Line Items]
Preferred stock dividends | $		$ 0	$ 18,437	$ 34,931
Depository Shares
Class of Stock [Line Items]
Depository shares issued					5,200,000
Preferred stock ownership interest						0.010
6.75% Series B Mandatory Convertible Preferred Stock
Class of Stock [Line Items]
Percentage of issued shares					6.75%
Offering price (in usd per share) | $ / shares					$ 100
Proceeds from offering, net | $					$ 501,000
Preferred stock converted in to common stock (in shares)	132.50
Number of common stock issued upon conversion (in shares)	6,900,000

Stockholder Rights Plan (Detail

Stockholder Rights Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 27, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Redemption price per share (in dollars per share)	$ 0.01
Preferred stock conversion	$ 400	$ 0	$ 0	$ (411)

Share Repurchases (Details)

Share Repurchases (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Nov. 29, 2018	May 25, 2017
Equity, Class of Treasury Stock [Line Items]
Shares repurchased	1,000,000	900,000
Value of shares repurchased	$ 35,000,000	$ 50,000,000	$ 175,000,000
Treasury stock acquired, average cost per share (in usd per share)	$ 35.83	$ 56.19
5/25/2017 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount (in usd)					$ 200,000,000
Shares repurchased		2,700,000
Value of shares repurchased		$ 175,000,000
Treasury stock acquired, average cost per share (in usd per share)		$ 64.94
11/29/2018 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount (in usd)				$ 300,000,000
Shares repurchased			0

Market Concentrations and Ris_2

Market Concentrations and Risks (Details) $ in Thousands, lb in Millions	12 Months Ended
	Dec. 31, 2020USD ($)lbDistributorCustomer	Dec. 31, 2019USD ($)CustomerDistributor	Dec. 31, 2018CustomerDistributor
Concentration Risk [Line Items]
Number of customers | Customer	10	10	10
Number of distributors | Distributor	6	6	6
Total senior subordinated notes	$ 1,590,810	$ 1,459,380
Senior Subordinated Notes
Concentration Risk [Line Items]
Fair value of debt instrument	$ 1,633,700	$ 1,532,700
Copper
Concentration Risk [Line Items]
Committed amounts to purchase (in pounds) | lb	1.9
Committed amounts to purchase (in usd)	$ 6,000
Gain (loss) on unconditional purchase obligation	$ 700
Customer Concentration Risk | Consolidated Revenues
Concentration Risk [Line Items]
Concentration risk, percentage	40.00%	39.00%	40.00%
Labor Force Concentration Risk | Workforce Subject to Collective Bargaining Arrangements
Concentration Risk [Line Items]
Concentration risk, percentage	28.00%
Labor Force Concentration Risk | Workforce Subject to Collective Bargaining Arrangements Expiring within One Year
Concentration Risk [Line Items]
Concentration risk, percentage	25.00%

Contingent Liabilities (Details

Contingent Liabilities (Details) $ in Millions	Dec. 31, 2020USD ($)
Standby Letters of Credit
Line of Credit Facility [Line Items]
Loss contingency, range of possible loss, portion not accrued	$ 8.5
Bank Guaranties
Line of Credit Facility [Line Items]
Loss contingency, range of possible loss, portion not accrued	4.1
Surety Bonds
Line of Credit Facility [Line Items]
Loss contingency, range of possible loss, portion not accrued	$ 3.3

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Income tax refunds received	$ 4,460	$ 4,695	$ 3,920
Income taxes paid	(25,259)	(40,760)	(52,147)
Interest paid	$ (53,029)	$ (51,160)	$ (48,519)

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Thousands	Jan. 29, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Subsequent Events [Line Items]
Cash used to acquire businesses, net of cash acquired		$ (590)	$ 74,392	$ 84,580
OTN Systems, N.V. [Member] | Subsequent Event
Subsequent Events [Line Items]
Cash used to acquire businesses, net of cash acquired	$ 71,000

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Currency Movement	$ 39
Accounts Receivable - Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	2,569	$ 3,137	$ 3,709
Charged to Costs and Expenses	2,282	159	353
Divestitures/ Acquisitions	0	368	0
Charge Offs		(969)	(567)
Recoveries	(637)	(86)	(176)
Currency Movement		(40)	(182)
Ending Balance	5,150	2,569	3,137
Inventories - Excess and Obsolete Allowances
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	21,245	17,364	19,887
Charged to Costs and Expenses	15,915	6,403	2,801
Divestitures/ Acquisitions	0	452	0
Charge Offs	(4,540)	(2,333)	(2,464)
Recoveries	(597)	(606)	(2,675)
Currency Movement	246	(35)	(185)
Ending Balance	32,269	21,245	17,364
Deferred Income Tax Asset - Valuation Allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	48,251	37,235	47,636
Charged to Costs and Expenses	3,142	12,356	13,459
Divestitures/ Acquisitions	33,003	330	(2)
Charge Offs	(303)	0	(22,577)
Recoveries	(114)	(1,629)	(928)
Currency Movement	329	(41)	(353)
Ending Balance	$ 84,308	$ 48,251	$ 37,235