Commitments and Contingencies (Details Textual)			1 Months Ended			3 Months Ended		9 Months Ended
	Jun. 30, 2013 USD ($) Launch Satellite	Mar. 31, 2010 USD ($) Launch	Nov. 30, 2016 USD ($)	Jun. 30, 2015 Launch	Jun. 30, 2010 USD ($)	Jun. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) Satellite	Sep. 30, 2016 USD ($)	Jul. 26, 2017 USD ($)	Dec. 31, 2016 USD ($)
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Guarantee amount								$ 1,000,000
Line of credit facility, maximum borrowing capacity								1,800,000,000
Credit facility, net								1,695,832,000			$ 1,657,145,000
Deferred financing costs								104,200,000
Credit facility								1,800,000,000
Minimum required cash reserve balance for credit facility								102,000,000
Syndicate of Bank Lenders Credit Facility [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Credit facility delays DSRA contributions								54,000,000
Refund amount contributed to DSRA								33,000,000
Additional refund amount contributed to DSRA								11,000,000
Credit facility, interest expense						$ 21,900,000	$ 19,800,000	64,700,000	$ 57,000,000
Syndicate of Bank Lenders Credit Facility [Member] | Maximum [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Projected available cash on three-month forward-looking basis								35,000,000
Syndicate of Bank Lenders Credit Facility [Member] | Aireon LLC [Member] | Maximum [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Hosting fees required to be placed in restricted account								$ 50,000,000
Syndicate of Bank Lenders Credit Facility [Member] | Series A Preferred Stock and Series B Preferred Stock [Member] | Aireon LLC [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Temporary suspension of dividend payments, term								15 months
Eighth Launch with SpaceX [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Number of additional satellites to launch | Satellite								5
Bills of Exchange [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Debt instrument face amount								$ 100,000,000
Debt instrument interest rate								1.62%
Debt instrument, basis spread on variable rate								1.40%
Debt Instrument, Milestone Payment								$ 28,900,000
Debt Issuance Costs, Net								900,000
Long-term Debt								28,000,000
Thales Alenia Space France [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Commitments Price For Design and Build Of Satellites					$ 2,300,000,000
Contract aggregate payment								1,909,000,000
Borrowings under credit facility								$ 1,511,400,000
Percentage of invoice paid by credit facility								85.00%
Percentage of invoice paid by cash								15.00%
Expected percentage of invoice paid by cash and marketable securities								100.00%
Liquidated damages										$ 30,000,000
Contractual Obligation, Due in Next Twelve Months								$ 247,200,000
Contractual Obligation, Due in Second Year								105,600,000
Thales Alenia Space France [Member] | Syndicate of Bank Lenders Credit Facility [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Description of utilization of hosting fees								50,000,000.0
Thales Alenia Space France [Member] | Promissory Note [Member] | Syndicate of Bank Lenders Credit Facility [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Debt instrument face amount								189,000,000
Space Exploration Technologies Corp [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Contract aggregate payment								447,400,000
Contractual Obligation, Due in Next Twelve Months								63,400,000
Contractual Obligation, Due in Second Year								$ 10,200,000
Space Exploration Technologies Corp [Member] | One to Seven Launch with SpaceX [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Number of launches for agreement | Launch		7
Maximum Commitments Amount		$ 453,100,000
Space Exploration Technologies Corp [Member] | SpaceX Falcon 9 Rocket [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Number of satellites carried to orbit for each of initial seven launches | Satellite								10
Space Exploration Technologies Corp [Member] | Eighth Launch with SpaceX [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Commitments price for launching of additional satellites			$ 67,900,000
Space Exploration Technologies Corp [Member] | GFZ German Research Centre for Geosciences [Member] | Eighth Launch with SpaceX [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Payment due from related party to share the launch services			$ 31,800,000
Cash received from related party								$ 28,600,000
Space Exploration Technologies Corp [Member] | GFZ German Research Centre for Geosciences [Member] | Gravity Recovery and Climate Experiment Follow-On Satellites [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Number of satellites to launch | Satellite								2
Kosmotras [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Contract aggregate payment								$ 36,800,000
Contractual Obligation, Due in Second Year								15,000,000
Number of launch option exercised | Launch	1
Number of Satellites to carry under exercised option | Satellite	2
Total contract amount	$ 51,800,000
Maximum number of dedicated launches purchased | Launch				6
Iridium NEXT Launch and In-Orbit Insurance [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Contract aggregate payment								63,500,000
Contractual Obligation, Due in Next Twelve Months								$ 54,700,000
Insurance coverage period								12 months
Insurance Policy Premium								$ 118,200,000
Estimated aggregate costs associated with launch of satellites								$ 3,000,000,000