XML 40 R30.htm IDEA: XBRL DOCUMENT
v3.21.2

Broadcast Licenses, Goodwill and Other Intangible Assets (Details) | 6 Months Ended
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Jun. 30, 2021
Customer relationships [Member] |
Finite-Lived Intangible Asset, Useful Life | 3 years
Maximum [Member] | Favorable lease agreements [Member] |
Finite-Lived Intangible Asset, Useful Life | 26 years
Maximum [Member] | Other Intangible [Member] |
Finite-Lived Intangible Asset, Useful Life | 15 years
Minimum [Member] | Favorable lease agreements [Member] |
Finite-Lived Intangible Asset, Useful Life | 5 years
Minimum [Member] | Other Intangible [Member] |
Finite-Lived Intangible Asset, Useful Life | 1 year

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- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=sga_FavorableLeaseAgreementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=sga_OtherIntangibleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |