SHARE-BASED COMPENSATION - Recognized Non-Cash Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense included in operating expenses	$ 9,255	$ 16,184	$ 15,149
Income tax benefit	2,222	3,703	3,160
After-tax stock-based compensation expense	7,033	12,481	11,989
Station operating expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense included in operating expenses	2,348	4,673	6,855
Corporate general and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense included in operating expenses	$ 6,907	$ 11,511	$ 8,294

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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