Debt Instrument, Compensating Balance, Required Amount

No definition available.

Name:	gsat_DebtInstrumentCompensatingBalanceRequiredAmount
Namespace Prefix:	gsat_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of Capital Stock Pledged as Collateral

+ References

No definition available.

+ Details

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Namespace Prefix:	gsat_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of guarantee provided by French export credit agency to lending syndicate.

+ References

No definition available.

+ Details

Name:	gsat_PercentageOfGuaranteeProvidedByCreditAgency
Namespace Prefix:	gsat_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of a specific compensating balance arrangement that is maintained under an agreement for a bank loan or future credit availability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CompensatingBalanceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Incremental percentage increase (decrease) in the stated rate on a debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentInterestRateIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	num: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

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=gsat_ForeignSubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix:
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Long-Term Debt and Other Financing Arrangements - Facility Agreement (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Sep. 30, 2019
Facility Agreement
Debt Instrument [Line Items]
Interest above LIBOR rate, percentage	3.75%
Percentage of guarantee provided by French export credit agency to lending syndicate	95.00%
Debt service reserve account	$ 60.6
Facility Agreement \| Domestic Subsidiaries
Debt Instrument [Line Items]
Percentage of equity pledged as collateral	100.00%
Facility Agreement \| Foreign Subsidiaries
Debt Instrument [Line Items]
Percentage of equity pledged as collateral	65.00%
Facility Agreement \| Minimum
Debt Instrument [Line Items]
Interest rate increase, percentage	0.50%
Facility Agreement \| Maximum
Debt Instrument [Line Items]
Interest rate increase, percentage	5.75%
Scenario, Forecast
Debt Instrument [Line Items]
Compensating balance, required amount		$ 5.0