INCOME TAXES - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Employee benefits - current	$ 0	$ 0
Provision for doubtful accounts - current	0	0
Deferred compensation - current	0	0
Deferred gain on tower transaction	0	0
Other	0	0
Total current deferred tax assets before valuation allowance	0	0
Valuation allowance	0	0
Total current deferred tax assets - net	0	0
Provision for doubtful accounts	4,383	795
Federal and state income tax loss carryforwards	96,334	126,278
Deferred compensation	11,601	5,307
Share-based compensation	4,174	3,145
Investments - impairments	348	499
Deferred gain on tower transaction, long term	1,897	3,035
Reserves	7,442	0
Debt fair value adjustment	5,162	0
Deferred Tax Liabilities, Property, Plant and Equipment	0	4,036
Employee benefits	543	944
Advertiser broadcasting obligations - noncurrent	0	47
Lease rental obligations	13,910	3,504
Other	1,614	1,532
Total non-current deferred tax assets before valuation allowance	147,408	149,122
Valuation allowance	37,154	12,861
Total non-current deferred tax assets - net	110,254	136,261
Deferred tax liabilities:
Advertiser broadcasting obligations - current	(7,172)	0
Total current deferred tax liabilities	0	0
Advertiser broadcasting obligations	(7,172)	0
Property equipment and certain intangibles	(55,922)	0
Broadcasting licenses and goodwill	(656,949)	(226,128)
Total deferred tax liabilities	(720,043)	(229,159)
Deferred Tax Assets (Liabilities), Net	609,789	$ 92,898
Estimated Income Tax Benefit -TCJA	$ 291,500