CONDENSED CONSOLIDATING FINANCIAL STATEMENTS - Narrative (Details) $ in Millions	Jun. 30, 2019 USD ($)
Debt Instrument [Line Items]
Consolidated total debt	$ 3,788.0
Subsidiary Issuer
Debt Instrument [Line Items]
Consolidated total debt	3,769.4
Amount of debt guaranteed by parent	$ 3,729.5
5.375% Senior Unsecured Notes due 2021 \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	5.375%
5.375% Senior Unsecured Notes due 2021 \| Sinclair Television Group, Inc. \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	5.375%
5.375% Senior Unsecured Notes due 2021 \| Guarantor Subsidiaries and KDSM, LLC \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	5.375%
5.625% Senior Unsecured Notes Due 2021 \| Sinclair Television Group, Inc. \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	5.625%
6.125% Senior Unsecured Notes due 2022 \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	6.125%
6.125% Senior Unsecured Notes due 2022 \| Sinclair Television Group, Inc. \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	6.125%
6.125% Senior Unsecured Notes due 2022 \| Guarantor Subsidiaries and KDSM, LLC \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	6.125%
5.875% Senior Unsecured Notes due 2026 \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	5.875%
5.875% Senior Unsecured Notes due 2026 \| Sinclair Television Group, Inc. \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	5.875%
5.875% Senior Unsecured Notes due 2026 \| Guarantor Subsidiaries and KDSM, LLC \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	5.875%
5.125% Senior Unsecured Notes due 2027 \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	5.125%
5.125% Senior Unsecured Notes due 2027 \| Sinclair Television Group, Inc. \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	5.125%
5.125% Senior Unsecured Notes due 2027 \| Guarantor Subsidiaries and KDSM, LLC \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	5.125%
5.625% Senior Unsecured Notes due 2024 \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	5.625%
5.625% Senior Unsecured Notes due 2024 \| Guarantor Subsidiaries and KDSM, LLC \| Senior Notes
Debt Instrument [Line Items]
Interest rate (as a percent)	5.625%

Debt And Capital Lease Obligations, Guaranteed

No definition available.

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

- Definition

Amount of short-term and long-term debt and lease obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13,16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

+ Details

Name:	us-gaap_DebtAndCapitalLeaseObligations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

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

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_SubsidiaryIssuerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=sbgi_SeniorUnsecuredNotes5.375PercentDue2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_SubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_GuarantorSubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=sbgi_SeniorUnsecuredNotes5.625PercentDue2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=sbgi_SeniorUnsecuredNotes6.125PercentDue2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=sbgi_SeniorUnsecuredNotes5.875PercentDue2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=sbgi_SeniorUnsecuredNotes5.125PercentDue2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=sbgi_SeniorUnsecuredNotes5.625PercentDue2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: