Note 1 - Basis of Presentation (Details Textual) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2018	Dec. 31, 2019
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

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