INCOME TAXES - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Federal and state income tax loss carryforwards	$ 88,815	$ 70,982
Share-based compensation	3,432	4,221
Investments - impairments	350	350
Lease rental obligations	3,469	4,709
Deferred compensation	8,938	10,253
Debt fair value adjustment	4,081	4,987
Reserves	514	0
Lease liability	71,968	77,722
Employee benefits	1,673	2,011
Provision for doubtful accounts	5,043	4,671
Other non-current	8,193	2,432
Total deferred tax assets before valuation allowance	196,476	182,338
Valuation allowance	(24,399)	(25,440)	$ (25,761)	$ (37,154)
Total deferred tax assets	172,077	156,898
Deferred tax liabilities:
Lease ROU asset	(63,186)	(69,243)
Property, equipment and certain intangibles	(49,908)	(43,788)
Broadcasting licenses and goodwill	(532,381)	(593,525)
Total deferred tax liabilities	(645,475)	(706,556)
Total net deferred tax liabilities	$ (473,398)	$ (549,658)