Credit Facility, Increase, Maximum Borrowing Amount

No definition available.

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Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument, Covenant Requirement, Leverage Ratio, Maximum

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Long-term Debt, Maturities, Gross Repayments of Principal in Next Twelve Months

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Long-term Debt, Maturities, Gross Repayments of Principal in Year Two

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Shelf Registration Statement Maximum Amount Of securities Authorized For Issuance

+ References

No definition available.

+ Details

Name:	tgna_ShelfRegistrationStatementMaximumAmountOfSecuritiesAuthorizedForIssuance
Namespace Prefix:	tgna_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Reduction in cash due to no longer including the former subsidiary's cash in the consolidated entity's cash.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of paid and unpaid cash dividends declared for classes of stock, for example, but not limited to, common and preferred.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
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-SubTopic 405
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-Paragraph 2
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Gross amount of debt extinguished.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The distributions of earnings to an entity that is affiliated with the reporting entity by means of direct or indirect ownership.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents the cash inflow during the period from the sale of a component of the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

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-Publisher FASB
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-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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- Details

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- Details

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- Details

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- Details

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Long-term debt - Narrative (Detail)					3 Months Ended
Long-term debt - Narrative (Detail)	Oct. 16, 2017 USD ($)	Aug. 01, 2017	Jul. 31, 2017 USD ($)	May 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Sep. 26, 2016 USD ($)	Sep. 23, 2015 USD ($)
Debt Instrument [Line Items]
Shelf registration statement maximum amount of securities authorized for issuance							$ 7,000,000,000
Contractual debt maturities, 2018							121,000,000
Contractual debt maturities, 2019							$ 420,000,000
Unsecured notes bearing fixed rate interest at 5.125% due October 2019
Debt Instrument [Line Items]
Early repayment of debt	$ 280,000,000
Interest rate stated percentage	5.125%						5.125%
Redemption price (as a percent)	101.281%
Line of Credit \| Amended and Restated Competitive Advance and Revolving Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity									$ 1,500,000,000.0
Revolving Credit Facility
Debt Instrument [Line Items]
Repayments of lines of credit				$ 609,900,000		$ 609,900,000
Unused borrowing capacity							$ 1,490,000,000
Revolving Credit Facility \| Amended and Restated Competitive Advance and Revolving Credit Agreement
Debt Instrument [Line Items]
Increase in borrowing capacity								$ 103,000,000
Cars.com \| Revolving Credit Facility
Debt Instrument [Line Items]
Proceeds from lines of credit						675,000,000
Payments of distributions to affiliates				$ 650,000,000		$ 650,000,000
Career Builder
Debt Instrument [Line Items]
Proceeds from sale of discontinued operation					$ 198,300,000
Cash transferred in sale of business					36,600,000
Dividend issued prior to sale			$ 25,800,000		$ 25,800,000
Debt Covenant, Period One \| Amended and Restated Competitive Advance and Revolving Credit Agreement
Debt Instrument [Line Items]
Covenant requirement, maximium total leverage ratio		5.0
Debt Covenant, Period Two \| Amended and Restated Competitive Advance and Revolving Credit Agreement
Debt Instrument [Line Items]
Covenant requirement, maximium total leverage ratio		4.75
Debt Covenant, Period Three \| Amended and Restated Competitive Advance and Revolving Credit Agreement
Debt Instrument [Line Items]
Covenant requirement, maximium total leverage ratio		4.5