Disposal Group, Including Discontinued Operation, Consideration, Notes Receivable

No definition available.

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Namespace Prefix:	bdc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Disposal Group, Including Discontinued Operation, Consideration, Notes Receivable, Interest Rate

+ References

No definition available.

+ Details

Name:	bdc_DisposalGroupIncludingDiscontinuedOperationConsiderationNotesReceivableInterestRate
Namespace Prefix:	bdc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Disposal Group, Including Discontinued Operations, Consideration Transferred, Maximum Earnout Consideration

+ References

No definition available.

+ Details

Name:	bdc_DisposalGroupIncludingDiscontinuedOperationsConsiderationTransferredMaximumEarnoutConsideration
Namespace Prefix:	bdc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Note Receivable, Term

+ References

No definition available.

+ Details

Name:	bdc_NoteReceivableTerm
Namespace Prefix:	bdc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

For transactions that are recognized separately from the acquisition of assets and assumptions of liabilities in the business combination, such as related to pre-existing relationships with the acquiree, this element represents the disclosure of the amount of acquisition related costs which have been expensed.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAcquisitionCostExpensed
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

+ References

No definition available.

+ Details

Name:	us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of cash outflow, made soon after acquisition date of business combination, to settle contingent consideration liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentForContingentConsiderationLiabilityInvestingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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Period Type:	duration

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=bdc_GrassValleyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DiscontinuedOperationsDisposedOfBySaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
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Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=bdc_SnellAdvancedMediaMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Subsequent Events (Details) - USD ($) $ in Millions			12 Months Ended
Subsequent Events (Details) - USD ($) $ in Millions	Feb. 04, 2020	Jan. 16, 2020	Dec. 31, 2018
Grass Valley \| Discontinued Operations, Disposed of by Sale \| Subsequent Event
Subsequent Events [Line Items]
Disposition, sales price	$ 140.0
Consideration, notes receivable	213.0
Maximum earnout consideration	$ 150.0
Consideration, notes receivable, interest rate	10.00%
Note receivable, term	5 years
Snell Advanced Media
Subsequent Events [Line Items]
Acquisition cost expensed			$ 0.9
Snell Advanced Media \| Subsequent Event
Subsequent Events [Line Items]
Payment for contingent consideration liability		$ 31.4