Asset Impairments, Other Charges, and Inventory Valuation Provision - Cash Charges (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Charges
Charges			$ 6,840
Restructuring Reserve [Roll Forward]
Balance as of Beginning of the period	$ 2,203	$ 4,013
Cash Payments Made	(249)	(1,810)	(2,827)
Balance as of End of period	1,954	2,203	4,013
Employee Severance
Cash Charges
Charges			2,757
Restructuring Reserve [Roll Forward]
Cash Payments Made			(2,757)
Lease termination fees and AROs for station closures
Cash Charges
Charges			4,083
Restructuring Reserve [Roll Forward]
Balance as of Beginning of the period	2,203	4,013
Cash Payments Made	(249)	(1,810)	(70)
Balance as of End of period	$ 1,954	$ 2,203	$ 4,013

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

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