CONDENSED CONSOLIDATING FINANCIAL STATEMENTS - Statement of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME
NET CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES	$ 372,905	$ 278,211
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:
Acquisition of property and equipment	(77,618)	(55,463)
Acquisition of businesses, net of cash acquired	0	(269,799)
Investments in equity investees	(25,624)	(22,302)
Proceeds from the sale of assets	1,087	195,182
Distributions from equity investees	23,533	6,642
Spectrum auction proceeds	0	310,802
Loans to affiliates	0
Other, net	(7,866)	(13,414)
Net cash flows (used in) from investing activities	(86,488)	151,648
CASH FLOWS (USED IN) FROM FINANCING ACTIVITIES:
Proceeds from notes payable and commercial bank financing	3,343	166,041
Repayments of notes payable, commercial bank financing and capital leases	(154,244)	(318,309)
Net proceeds from the sale of Class A Common Stock	0	487,883
Dividends paid on Class A and Class B Common Stock	(55,205)	(53,049)
Distributions to noncontrolling interests	(6,871)	(20,469)
Repurchase of outstanding Class A Common Stock	(45,904)	(30,287)
Increase (decrease) in intercompany payables	0	0
Other, net	1,006	(5,357)
Net cash flows (used in) from financing activities	(257,875)	226,453
NET INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	28,542	656,312
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, beginning of period	995,940	260,184
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, end of period	1,024,482	916,496
Reportable legal entities | Sinclair Broadcast Group, Inc.
CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME
NET CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES	(8,331)	(5,605)
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:
Acquisition of property and equipment	(1)	(131)
Acquisition of businesses, net of cash acquired		0
Investments in equity investees	(1,767)	(945)
Proceeds from the sale of assets	0	0
Distributions from equity investees	6,398	3,903
Spectrum auction proceeds		0
Loans to affiliates	0
Other, net	0	0
Net cash flows (used in) from investing activities	4,630	2,827
CASH FLOWS (USED IN) FROM FINANCING ACTIVITIES:
Proceeds from notes payable and commercial bank financing	0	0
Repayments of notes payable, commercial bank financing and capital leases	0	0
Net proceeds from the sale of Class A Common Stock		487,883
Dividends paid on Class A and Class B Common Stock	(55,205)	(53,049)
Distributions to noncontrolling interests	0	0
Repurchase of outstanding Class A Common Stock	(45,904)	(30,287)
Increase (decrease) in intercompany payables	102,927	(400,451)
Other, net	1,883	(1,318)
Net cash flows (used in) from financing activities	3,701	2,778
NET INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	0	0
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, beginning of period	0	0
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, end of period	0	0
Reportable legal entities | Sinclair Television Group, Inc.
CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME
NET CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES	(232,158)	(141,240)
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:
Acquisition of property and equipment	(5,315)	(6,088)
Acquisition of businesses, net of cash acquired		(8,308)
Investments in equity investees	(1,488)	(1,101)
Proceeds from the sale of assets	0	0
Distributions from equity investees	0	0
Spectrum auction proceeds		0
Loans to affiliates	0
Other, net	(7,866)	(7,732)
Net cash flows (used in) from investing activities	(14,669)	(23,229)
CASH FLOWS (USED IN) FROM FINANCING ACTIVITIES:
Proceeds from notes payable and commercial bank financing	0	159,669
Repayments of notes payable, commercial bank financing and capital leases	(140,721)	(200,119)
Net proceeds from the sale of Class A Common Stock		0
Dividends paid on Class A and Class B Common Stock	0	0
Distributions to noncontrolling interests	0	0
Repurchase of outstanding Class A Common Stock	0	0
Increase (decrease) in intercompany payables	688,478	524,016
Other, net	0	(45)
Net cash flows (used in) from financing activities	547,757	483,521
NET INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	300,930	319,052
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, beginning of period	645,830	232,297
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, end of period	946,760	551,349
Reportable legal entities | Guarantor Subsidiaries and KDSM, LLC
CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME
NET CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES	622,165	433,236
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:
Acquisition of property and equipment	(71,639)	(47,564)
Acquisition of businesses, net of cash acquired		(261,491)
Investments in equity investees	(20,863)	(15,469)
Proceeds from the sale of assets	1,087	541
Distributions from equity investees	0	0
Spectrum auction proceeds		187,854
Loans to affiliates	0
Other, net	0	0
Net cash flows (used in) from investing activities	(91,415)	(136,129)
CASH FLOWS (USED IN) FROM FINANCING ACTIVITIES:
Proceeds from notes payable and commercial bank financing	0	0
Repayments of notes payable, commercial bank financing and capital leases	(2,653)	(1,367)
Net proceeds from the sale of Class A Common Stock		0
Dividends paid on Class A and Class B Common Stock	0	0
Distributions to noncontrolling interests	0	0
Repurchase of outstanding Class A Common Stock	0	0
Increase (decrease) in intercompany payables	(839,781)	(92,993)
Other, net	0	(3,607)
Net cash flows (used in) from financing activities	(842,434)	(97,967)
NET INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	(311,684)	199,140
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, beginning of period	323,383	10,875
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, end of period	11,699	210,015
Reportable legal entities | Non- Guarantor Subsidiaries
CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME
NET CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES	(18,789)	(12,959)
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:
Acquisition of property and equipment	(3,352)	(2,677)
Acquisition of businesses, net of cash acquired		0
Investments in equity investees	(1,506)	(4,787)
Proceeds from the sale of assets	0	194,641
Distributions from equity investees	17,135	2,739
Spectrum auction proceeds		122,948
Loans to affiliates	0
Other, net	0	(5,682)
Net cash flows (used in) from investing activities	12,277	307,182
CASH FLOWS (USED IN) FROM FINANCING ACTIVITIES:
Proceeds from notes payable and commercial bank financing	3,343	6,372
Repayments of notes payable, commercial bank financing and capital leases	(11,159)	(116,823)
Net proceeds from the sale of Class A Common Stock		0
Dividends paid on Class A and Class B Common Stock	0	0
Distributions to noncontrolling interests	(6,871)	(20,469)
Repurchase of outstanding Class A Common Stock	0	0
Increase (decrease) in intercompany payables	61,372	(24,750)
Other, net	(877)	(433)
Net cash flows (used in) from financing activities	45,808	(156,103)
NET INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	39,296	138,120
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, beginning of period	26,727	17,012
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, end of period	66,023	155,132
Eliminations
CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME
NET CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES	10,018	4,779
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:
Acquisition of property and equipment	2,689	997
Acquisition of businesses, net of cash acquired		0
Investments in equity investees	0	0
Proceeds from the sale of assets	0	0
Distributions from equity investees	0	0
Spectrum auction proceeds		0
Loans to affiliates	0
Other, net	0	0
Net cash flows (used in) from investing activities	2,689	997
CASH FLOWS (USED IN) FROM FINANCING ACTIVITIES:
Proceeds from notes payable and commercial bank financing	0	0
Repayments of notes payable, commercial bank financing and capital leases	289	0
Net proceeds from the sale of Class A Common Stock		0
Dividends paid on Class A and Class B Common Stock	0	0
Distributions to noncontrolling interests	0	0
Repurchase of outstanding Class A Common Stock	0	0
Increase (decrease) in intercompany payables	(12,996)	(5,822)
Other, net	0	46
Net cash flows (used in) from financing activities	(12,707)	(5,776)
NET INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	0	0
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, beginning of period	0	0
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, end of period	$ 0	$ 0