QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Total revenues, net	$ 797,691	$ 693,835	$ 666,534	$ 578,889	$ 611,790	$ 548,404	$ 554,167	$ 504,775	$ 2,736,949	$ 2,219,136	$ 1,976,558
Operating income	233,446	153,994	129,074	86,339	124,243	99,606	114,340	84,547	602,853	422,736	494,651
Net Income	122,500	52,033	50,600	25,629	60,830	44,034	46,399	24,836	250,762	176,099	215,115
Net income attributable to Sinclair Broadcast Group	$ 120,897	$ 50,845	$ 49,419	$ 24,140	$ 58,200	$ 43,255	$ 45,787	$ 24,282	$ 245,301	$ 171,524	$ 212,279
Basic earnings per share common shares (in dollars per share)	$ 1.34	$ 0.54	$ 0.52	$ 0.25	$ 0.62	$ 0.46	$ 0.48	$ 0.26	$ 2.62	$ 1.81	$ 2.19
Diluted earnings per share common shares (in dollars per share)	$ 1.32	$ 0.54	$ 0.52	$ 0.25	$ 0.61	$ 0.45	$ 0.48	$ 0.25	$ 2.60	$ 1.79	$ 2.17