Credit facility participation fee and fronting fee percentage.

No definition available.

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Namespace Prefix:	sga_
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Period Type:	duration

- Definition

Debt instrument term post extension.

+ References

No definition available.

+ Details

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Namespace Prefix:	sga_
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- Definition

Amount of amortization expense attributable to debt issuance costs.

+ References

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+ Details

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

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- 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

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, 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

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The effective interest rate at the end of the reporting period.

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- 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

+ Details

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Namespace Prefix:	us-gaap_
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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

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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+ Details

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

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

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- Details

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Long-Term Debt (Narrative) (Details) - USD ($)			1 Months Ended	6 Months Ended
Long-Term Debt (Narrative) (Details) - USD ($)	Jun. 27, 2018	Aug. 15, 2015	Aug. 18, 2015	Jun. 30, 2021	Dec. 31, 2020	Jul. 01, 2019
Debt Instrument [Line Items]
Long-term debt				$ 10,000,000	$ 10,000,000
Credit facility participation fee and fronting fee percentage				0.25%
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Line of credit facility, interest rate at period end				0.125%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 100,000,000
Debt instrument, maturity date	Jun. 27, 2023		Aug. 18, 2020
Line of Credit Facility, Remaining Borrowing Capacity				$ 60,000,000
Amortization of debt issuance costs				$ 266,000
Debt instrument, term		5 years
Debt instrument term post extension	5 years
Minimum [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.00%
Minimum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.00%
Minimum [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, commitment fee percentage				0.20%
Maximum [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.00%
Maximum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				2.00%
Maximum [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, commitment fee percentage				0.30%
Second Amendment [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Amortization of debt issuance costs				$ 120,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term debt				$ 10,000,000	$ 10,000,000
Revolving Credit Facility [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity						$ 70,000,000