Represents the annual percentage increase in aggregate purchase price of the television stations.

No definition available.

Name:	sbgi_BusinessAcquisitionAnnualIncreaseInAggregatePurchasePrice
Namespace Prefix:	sbgi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the amount of remaining purchase price, difference of aggregate purchase price and total payments made in pursuant to the business acquisition.

+ References

No definition available.

+ Details

Name:	sbgi_BusinessAcquisitionCostOfAcquiredEntityRemainingPurchasePrice
Namespace Prefix:	sbgi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Equipment Purchase Agreement, Annual Service Consideration

+ References

No definition available.

+ Details

Name:	sbgi_EquipmentPurchaseAgreementAnnualServiceConsideration
Namespace Prefix:	sbgi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Equipment Purchase Agreement, Consideration Amount

+ References

No definition available.

+ Details

Name:	sbgi_EquipmentPurchaseAgreementConsiderationAmount
Namespace Prefix:	sbgi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Loan Receivable, Interest Rate

+ References

No definition available.

+ Details

Name:	sbgi_LoanReceivableInterestRate
Namespace Prefix:	sbgi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Purchase Options, Broadcast Stations

+ References

No definition available.

+ Details

Name:	sbgi_PurchaseOptionsBroadcastStations
Namespace Prefix:	sbgi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the renewal period of agreements by related parties.

+ References

No definition available.

+ Details

Name:	sbgi_RelatedPartyTransactionAgreementRenewalPeriod
Namespace Prefix:	sbgi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount used to determine annual LMA fees required to be paid to related party.

+ References

No definition available.

+ Details

Name:	sbgi_RelatedPartyTransactionAmountUsedToDetermineAnnualLMAFeesRequiredToBePaid
Namespace Prefix:	sbgi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the number of renewal periods of agreements by related parties.

+ References

No definition available.

+ Details

Name:	sbgi_RelatedPartyTransactionNumberOfAgreementRenewalTerms
Namespace Prefix:	sbgi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount paid for transactions to related party during the financial reporting period.

+ References

No definition available.

+ Details

Name:	sbgi_RelatedPartyTransactionPaymentsToRelatedParty
Namespace Prefix:	sbgi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the percentage of each station's net broadcast revenue due to the related party used to determine amount of annual LMA fees required to be paid.

+ References

No definition available.

+ Details

Name:	sbgi_RelatedPartyTransactionPercentageOfAnnualNetBroadcastRevenueUsedToDetermineAnnualLMAFeesRequiredToBePaid
Namespace Prefix:	sbgi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of capital stock or assets to be acquired in business combination.

+ References

No definition available.

+ Details

Name:	sbgi_RelatedPartyTransactionRightToAcquireCapitalStockOfRelatedPartyPercentage
Namespace Prefix:	sbgi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Share Service Agreement, Annual Service Consideration

+ References

No definition available.

+ Details

Name:	sbgi_ShareServiceAgreementAnnualServiceConsideration
Namespace Prefix:	sbgi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of interest income earned from interest-bearing assets owed to the entity by related party.

+ References

No definition available.

+ Details

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

- Definition

Reflects the amount of new advances made to related parties in the form of loan and lease receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(e))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the sum of all other revenue and income realized from sales and other transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period.

+ References

No definition available.

+ Details

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

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_AffiliatedEntityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CounterpartyNameAxis=sbgi_CunninghamBroadcastingCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	sbgi_RelatedPartyTransactionsByTypeOfServicesAxis=sbgi_LocalMarketingAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=sbgi_CunninghamLicenseRelatedAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

RELATED PERSON TRANSACTIONS - Cunningham Broadcasting Corporation (Details) $ in Thousands	1 Months Ended			3 Months Ended		9 Months Ended
	Aug. 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Jan. 31, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) renewal	Sep. 30, 2016 USD ($)
Related Party Transaction [Line Items]
Net revenue				$ 670,891	$ 693,835	$ 2,000,115	$ 1,939,258
Affiliated Entity \| Cunningham
Related Party Transaction [Line Items]
Agreement renewal period			1 year
Right to acquire capital stock				100.00%		100.00%
Remaining purchase price				$ 53,600		$ 53,600
Purchase options, broadcast stations				200		200
Related party promissory note			$ 19,500
Loan receivable, interest rate			5.00%
Related party interest income				200	200	$ 700	700
Proceeds from sale of master control equipment		$ 700
Annual revenue from master control services		$ 200
Annual revenue for share service	$ 1,000
Affiliated Entity \| Cunningham \| LMA
Related Party Transaction [Line Items]
Number of additional renewal terms \| renewal						2
Agreement renewal period						5 years
Lease payments made to entities				$ 2,400	2,100	$ 6,400	6,600
Affiliated Entity \| Cunningham \| LMA \| Minimum
Related Party Transaction [Line Items]
Percentage of net broadcast revenue used to determine annual LMA fees required to be paid				3.00%		3.00%
Amount used to determine annual LMA fees required to be paid				$ 4,700		$ 4,700
Annual increase in aggregate purchase price				6.00%		6.00%
Cunningham license related assets \| Cunningham
Related Party Transaction [Line Items]
Agreement renewal period						8 years
Amount received				$ 6,600	1,400	$ 10,900	3,900
Net revenue				$ 31,400	$ 29,400	$ 84,500	$ 83,800