Nature of Business and Significant Accounting Policies - Allowance For Doubtful Accounts and Programming Rights (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Accounts receivable:
Threshold period for considering receivable as past due	90 days
Changes in the allowance for doubtful accounts
Beginning of Year	$ 507	$ 2,645
Provisions for bad debt	922	135
Write-offs	577	2,274
Recoveries	67	1
End of Year	919	507
Programming rights:
Impairment of programming rights	900	0
Amortization of programming rights	16,841	13,648
Accumulated amortization of programming rights	$ 75,500	$ 58,700