NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Variable Interest Entities (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) license	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) license
Variable Interest Entity [Line Items]
Media revenues	$ 693,835	$ 548,404	$ 1,939,258	$ 1,607,346
Income (loss) from equity investments	1,423	252	2,789	5,405
Eliminations
Variable Interest Entity [Line Items]
Media revenues	(25,820)	(20,538)	$ (67,313)	(60,584)
Consolidated VIEs, aggregated
Variable Interest Entity [Line Items]
Initial term of certain outsourcing agreements			5 years
Number of licensees as VIEs (license) | license			37		37
Media revenues	79,100	71,000	$ 227,400	207,600
Consolidated VIEs | Eliminations
Variable Interest Entity [Line Items]
Liabilities associated with the certain outsourcing agreements and purchase options	77,800		77,800		$ 72,500
Consolidated VIEs | Cunningham | Eliminations
Variable Interest Entity [Line Items]
Total payments made under the LMA excluded from liabilities	40,000		40,000		37,600
Total capital leased liabilities excluded from VIE consolidation	4,500		4,500		4,500
VIEs which are not primary beneficiary
Variable Interest Entity [Line Items]
Carrying amount	119,900		119,900		$ 18,100
Income (loss) from equity investments	$ 1,400	$ 700	$ 2,800	$ 6,500