Related Party Transaction, Data Service Fees

No definition available.

Name:	irdm_RelatedPartyTransactionDataServiceFees
Namespace Prefix:	irdm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Related Party Transaction, Forecasted Additional Payment

+ References

No definition available.

+ Details

Name:	irdm_RelatedPartyTransactionForecastedAdditionalPayment
Namespace Prefix:	irdm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Related Party Transaction, Forecasted Semi-Annual Payments

+ References

No definition available.

+ Details

Name:	irdm_RelatedPartyTransactionForecastedSemiAnnualPayments
Namespace Prefix:	irdm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Related Party Transaction, Hosting Fees

+ References

No definition available.

+ Details

Name:	irdm_RelatedPartyTransactionHostingFees
Namespace Prefix:	irdm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Related Party Transaction, Power Fees Per Year

+ References

No definition available.

+ Details

Name:	irdm_RelatedPartyTransactionPowerFeesPerYear
Namespace Prefix:	irdm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07.1(c))
-URI http://asc.fasb.org/extlink&oid=6488393&loc=d3e606610-122999

+ Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_EquityMethodInvesteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=irdm_AdministrationServicesAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=irdm_DataServicesAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=irdm_AmendedHostingAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=irdm_HostingAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Related Party Transactions (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Jul. 31, 2018	Jun. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Ownership stake		35.70%	35.70%
Equity Method Investee \| Administration Services Agreement
Related Party Transaction [Line Items]
Revenue from related parties			$ 1.0	$ 0.6
Equity Method Investee \| Data Services Agreement
Related Party Transaction [Line Items]
Revenue from related parties		$ 2.1	3.6
Equity Method Investee \| Amended Hosting Agreement
Related Party Transaction [Line Items]
Revenue from related parties			6.9
Equity Method Investee \| Hosting Agreement
Related Party Transaction [Line Items]
Hosting fees			200.0
Additional power fees			2.8
Data service fees			$ 19.8
Revenue from related parties		$ 8.1
Equity Method Investee \| Subsequent Event \| Amended Hosting Agreement
Related Party Transaction [Line Items]
Forecasted additional payment	$ 6.4
Forecasted semi-annual payments	$ 8.0