SHARE-BASED COMPENSATION - Non Cash Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense included in operating expenses	$ 4,428	$ 1,945	$ 9,780	$ 6,168
Income tax benefit	1,054	480	2,219	1,452
After-tax stock-based compensation expense	3,374	1,465	7,561	4,716
Station operating expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense included in operating expenses	937	524	3,054	1,552
Corporate general and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense included in operating expenses	$ 3,491	$ 1,421	$ 6,726	$ 4,616

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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-Name Accounting Standards Codification
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