ACQUISITIONS AND DISPOSITIONS OF ASSETS - Acquired Operations Included in the Financial Statements (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Acquisitions
Media revenues	[1]									$ 2,918,727	$ 2,566,936	$ 2,520,676
Operating income (loss)		$ 262,954	$ 157,810	$ 131,583	$ 107,314	$ 357,581	$ 103,447	$ 118,849	$ 157,629	659,661	737,506	602,853
Bonten
Acquisitions
Media revenues										100,971	30,907	0
Operating income (loss)										21,479	7,448	0
Tennis Channel
Acquisitions
Media revenues										143,047	132,584	84,040
Operating income (loss)										14,887	19,420	(1,990)
Other Acquisitions In 2017
Acquisitions
Media revenues										17,979	11,108	0
Operating income (loss)										(2,035)	(89)	0
Other Acquisitions In 2016
Acquisitions
Media revenues										81,003	66,698	49,186
Operating income (loss)										25,523	18,392	18,311
Total Acquisitions
Acquisitions
Media revenues										343,000	241,297	133,226
Operating income (loss)										$ 59,854	$ 45,171	$ 16,321

[1] See Revenue Recognition within Note 1. Nature of Operations and Summary of Significant Accounting Policies for a discussion of the adoption of the new accounting principles for revenue recognition.