Note 1 - Basis of Presentation (Details Textual) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2017
Period for Creating Allowance for Doubtful Accounts		120 days
Scenario, Forecast [Member] \| Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncement Effect, Lease Obligation Liability	$ 17.6
New Accounting Pronouncement Effect, Right of Use Assets	$ 17.6

Amount of effect of a change in accounting principle on lease obligation liability.

No definition available.

Name:	gtn_NewAccountingPronouncementEffectLeaseObligationLiability
Namespace Prefix:	gtn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration