CONDENSED CONSOLIDATED FINANCIAL STATEMENTS - Balance Sheets (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		$ 681,326	$ 259,984	$ 149,972	$ 17,682	$ 17,682
Restricted cash, current		313,110	200
Accounts and other receivables		566,464	513,954
Other current assets		153,847	131,150
Total current assets		1,714,747	905,088
Property and equipment, net		738,298	717,576
Investment in consolidated subsidiaries		0	0
Other long-term assets		246,351	249,049
Goodwill		2,124,033	1,990,746	1,931,093
Indefinite-lived intangible assets		159,371	156,306
Definite-lived intangible assets, net		1,801,670	1,944,403
Total assets	[1]	6,784,470	5,963,168
Accounts payable and accrued liabilities		370,403	328,545
Current portion of long-term debt		159,382	171,131
Current portion of affiliate long-term debt		1,667	3,604
Other current liabilities		194,897	133,193
Total current liabilities		726,349	636,473
Long-term debt		3,875,116	4,014,932
Affiliate long-term debt		12,485	14,181
Other liabilities		636,154	739,646
Total liabilities	[1]	5,250,104	5,405,232
Total Sinclair Broadcast Group shareholders’ equity		1,568,738	587,983
Noncontrolling interests		(34,372)	(30,047)
Total liabilities and equity		6,784,470	5,963,168
Reportable legal entities | Sinclair Broadcast Group, Inc.
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		0	0	0		0
Restricted cash, current		0
Accounts and other receivables		0	0
Other current assets		3,034	5,561
Total current assets		3,034	5,561
Property and equipment, net		829	1,820
Investment in consolidated subsidiaries		1,537,337	551,250
Other long-term assets		31,757	46,586
Goodwill		0	0
Indefinite-lived intangible assets		0	0
Definite-lived intangible assets, net		0	0
Total assets		1,572,957	605,217
Accounts payable and accrued liabilities		1,100	100
Current portion of long-term debt		0	0
Current portion of affiliate long-term debt		0	1,857
Other current liabilities		0	0
Total current liabilities		1,100	1,957
Long-term debt		0	0
Affiliate long-term debt		0	0
Other liabilities		3,119	15,277
Total liabilities		4,219	17,234
Total Sinclair Broadcast Group shareholders’ equity		1,568,738	587,983
Noncontrolling interests		0	0
Total liabilities and equity		1,572,957	605,217
Reportable legal entities | Sinclair Television Group, Inc.
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		645,830	232,297	115,771		3,394
Restricted cash, current		0
Accounts and other receivables		0	0
Other current assets		5,758	3,143
Total current assets		651,588	235,440
Property and equipment, net		31,111	17,925
Investment in consolidated subsidiaries		4,116,241	3,614,605
Other long-term assets		770,312	819,506
Goodwill		0	0
Indefinite-lived intangible assets		0	0
Definite-lived intangible assets, net		0	0
Total assets		5,569,252	4,687,476
Accounts payable and accrued liabilities		84,326	69,118
Current portion of long-term debt		148,505	55,501
Current portion of affiliate long-term debt		0	0
Other current liabilities		0	0
Total current liabilities		232,831	124,619
Long-term debt		3,799,987	3,939,463
Affiliate long-term debt		0	0
Other liabilities		38,282	31,817
Total liabilities		4,071,100	4,095,899
Total Sinclair Broadcast Group shareholders’ equity		1,498,152	591,577
Noncontrolling interests		0	0
Total liabilities and equity		5,569,252	4,687,476
Reportable legal entities | Guarantor Subsidiaries and KDSM, LLC
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		12,273	10,675	235		1,749
Restricted cash, current		311,110
Accounts and other receivables		530,273	478,190
Other current assets		145,637	124,313
Total current assets		999,293	613,178
Property and equipment, net		586,950	570,289
Investment in consolidated subsidiaries		4,179	4,179
Other long-term assets		104,363	103,808
Goodwill		2,120,166	1,986,467
Indefinite-lived intangible assets		145,073	140,597
Definite-lived intangible assets, net		1,781,045	1,770,512
Total assets		5,741,069	5,189,030
Accounts payable and accrued liabilities		261,266	231,640
Current portion of long-term debt		2,103	1,851
Current portion of affiliate long-term debt		1,342	1,514
Other current liabilities		180,616	121,972
Total current liabilities		445,327	356,977
Long-term debt		28,493	31,014
Affiliate long-term debt		11,237	12,663
Other liabilities		1,141,266	1,190,717
Total liabilities		1,626,323	1,591,371
Total Sinclair Broadcast Group shareholders’ equity		4,114,746	3,597,659
Noncontrolling interests		0	0
Total liabilities and equity		5,741,069	5,189,030
Reportable legal entities | Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		23,223	17,012	33,966		12,539
Restricted cash, current		2,000
Accounts and other receivables		36,191	37,024
Other current assets		9,687	25,406
Total current assets		71,101	79,442
Property and equipment, net		132,010	131,326
Investment in consolidated subsidiaries		0	0
Other long-term assets		208,367	169,817
Goodwill		3,867	4,279
Indefinite-lived intangible assets		14,298	15,709
Definite-lived intangible assets, net		77,944	233,368
Total assets		507,587	633,941
Accounts payable and accrued liabilities		36,029	48,860
Current portion of long-term debt		8,774	113,779
Current portion of affiliate long-term debt		871	2,336
Other current liabilities		14,281	13,545
Total current liabilities		59,955	178,520
Long-term debt		46,636	44,455
Affiliate long-term debt		334,491	396,957
Other liabilities		187,569	183,418
Total liabilities		628,651	803,350
Total Sinclair Broadcast Group shareholders’ equity		(82,051)	(134,991)
Noncontrolling interests		(39,013)	(34,418)
Total liabilities and equity		507,587	633,941
Eliminations
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		0	0	$ 0		$ 0
Restricted cash, current		0
Accounts and other receivables		0	(1,260)
Other current assets		(10,269)	(27,273)
Total current assets		(10,269)	(28,533)
Property and equipment, net		(12,602)	(3,784)
Investment in consolidated subsidiaries		(5,657,757)	(4,170,034)
Other long-term assets		(868,448)	(890,668)
Goodwill		0	0
Indefinite-lived intangible assets		0	0
Definite-lived intangible assets, net		(57,319)	(59,477)
Total assets		(6,606,395)	(5,152,496)
Accounts payable and accrued liabilities		(12,318)	(21,173)
Current portion of long-term debt		0	0
Current portion of affiliate long-term debt		(546)	(2,103)
Other current liabilities		0	(2,324)
Total current liabilities		(12,864)	(25,600)
Long-term debt		0	0
Affiliate long-term debt		(333,243)	(395,439)
Other liabilities		(734,082)	(681,583)
Total liabilities		(1,080,189)	(1,102,622)
Total Sinclair Broadcast Group shareholders’ equity		(5,530,847)	(4,054,245)
Noncontrolling interests		4,641	4,371
Total liabilities and equity		$ (6,606,395)	$ (5,152,496)

[1] Our consolidated total assets as of December 31, 2017 and 2016 include total assets of variable interest entities (VIEs) of $130.6 million and $142.3 million, respectively, which can only be used to settle the obligations of the VIEs. Our consolidated total liabilities as of December 31, 2017 and 2016 include total liabilities of the VIEs of $27.0 million and $40.9 million, respectively, for which the creditors of the VIEs have no recourse to us. See Note 1. Nature of Operations and Summary of Significant Accounting Policies.