Note 8 - Retirement Plans - Target Asset Allocation (Details)	12 Months Ended
Dec. 31, 2016
Large Cap Value [Member]
Target range, strategic allocation	5.00%
Target range, lower limit	0.00%
Target range, upper limit	50.00%
Large Cap Blend [Member]
Target range, strategic allocation	5.00%
Target range, lower limit	0.00%
Target range, upper limit	50.00%
Large Cap Growth [Member]
Target range, strategic allocation	5.00%
Target range, lower limit	0.00%
Target range, upper limit	50.00%
Mid-cap Blend [Member]
Target range, strategic allocation	15.00%
Target range, lower limit	0.00%
Target range, upper limit	40.00%
Small Cap Core [Member]
Target range, strategic allocation	5.00%
Target range, lower limit	0.00%
Target range, upper limit	25.00%
Foreign Large Blend [Member]
Target range, strategic allocation	10.00%
Target range, lower limit	0.00%
Target range, upper limit	40.00%
Emerging Markets [Member]
Target range, strategic allocation	10.00%
Target range, lower limit	0.00%
Target range, upper limit	25.00%
Real Estate [Member]
Target range, strategic allocation	5.00%
Target range, lower limit	0.00%
Target range, upper limit	20.00%
US Treasury Securities [Member]
Target range, strategic allocation	5.00%
Target range, lower limit	0.00%
Target range, upper limit	25.00%
Intermediate Term Bond [Member]
Target range, strategic allocation	10.00%
Target range, lower limit	0.00%
Target range, upper limit	50.00%
US Government Agencies Debt Securities [Member]
Target range, strategic allocation	5.00%
Target range, lower limit	0.00%
Target range, upper limit	40.00%
High Yield Bond [Member]
Target range, strategic allocation	10.00%
Target range, lower limit	0.00%
Target range, upper limit	25.00%
Emerging Markets Bond [Member]
Target range, strategic allocation	10.00%
Target range, lower limit	0.00%
Target range, upper limit	20.00%
Money Market Funds [Member]
Target range, strategic allocation	0.00%
Target range, lower limit	0.00%
Target range, upper limit	100.00%

Target allocation of investments of this type to total plan assets presented on a weighted average basis.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)(i)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2446-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Target allocation maximum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanTargetPlanAssetAllocationsRangeMaximum
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Target allocation minimum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)(i)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2446-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanTargetPlanAssetAllocationsRangeMinimum
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=gtn_LargeCapValueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=gtn_LargeCapBlendMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=gtn_LargeCapGrowthMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=gtn_MidCapBlendMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=gtn_SmallCapCoreMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=gtn_ForeignLargeBlendMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=gtn_EmergingMarketsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_RealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=gtn_IntermediateTermBondMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=gtn_HighYieldBondMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=gtn_EmergingMarketsBondMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: