CONDENSED CONSOLIDATED FINANCIAL STATEMENTS - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Aug. 30, 2016	Aug. 15, 2016
Condensed Financial Statements, Captions [Line Items]
Consolidated total debt	$ 4,048.7
Sinclair Television Group, Inc.
Condensed Financial Statements, Captions [Line Items]
Amount of debt guaranteed by parent	4,022.8
Sinclair Broadcast Group, Inc.
Condensed Financial Statements, Captions [Line Items]
Amount of debt guaranteed by parent	$ 3,977.8
Senior Notes | 5.375% Senior Unsecured Notes due 2021
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	5.375%	5.375%
Senior Notes | 5.375% Senior Unsecured Notes due 2021 | Sinclair Television Group, Inc.
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	5.375%
Senior Notes | 5.375% Senior Unsecured Notes due 2021 | Guarantor Subsidiaries and KDSM, LLC
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	5.375%
Senior Notes | 5.625% Senior Unsecured Notes due 2024
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	5.625%
Senior Notes | 5.625% Senior Unsecured Notes due 2024 | Guarantor Subsidiaries and KDSM, LLC
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	5.625%
Senior Notes | 5.625% Senior Notes, due | Sinclair Television Group, Inc.
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	5.625%
Senior Notes | 6.125% Senior Unsecured Notes due 2022
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	6.125%	6.125%
Senior Notes | 6.125% Senior Unsecured Notes due 2022 | Sinclair Television Group, Inc.
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	6.125%
Senior Notes | 6.125% Senior Unsecured Notes due 2022 | Guarantor Subsidiaries and KDSM, LLC
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	6.125%
Senior Notes | 5.875% Senior Unsecured Notes due 2026
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	5.875%	5.875%
Senior Notes | 5.875% Senior Unsecured Notes due 2026 | Sinclair Television Group, Inc.
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	5.875%
Senior Notes | 5.875% Senior Unsecured Notes due 2026 | Guarantor Subsidiaries and KDSM, LLC
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	5.875%
Senior Notes | 5.125% Senior Unsecured Notes due 2027
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	5.125%	5.125%	5.125%
Senior Notes | 5.125% Senior Unsecured Notes due 2027 | Sinclair Television Group, Inc.
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	5.125%
Senior Notes | 5.125% Senior Unsecured Notes due 2027 | Guarantor Subsidiaries and KDSM, LLC
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	5.125%
Senior Notes | 6.375% Senior Unsecured Notes due 2021
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)				6.375%
Senior Notes | 6.375% Senior Unsecured Notes due 2021 | Sinclair Television Group, Inc.
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	6.375%
Senior Notes | 6.375% Senior Unsecured Notes due 2021 | Guarantor Subsidiaries and KDSM, LLC
Condensed Financial Statements, Captions [Line Items]
Interest rate (as a percent)	6.375%