Commitments and Contingencies - Part 1 (Details)					1 Months Ended		3 Months Ended		9 Months Ended
	Jun. 05, 2017 USD ($)	May 22, 2017 USD ($)	Oct. 03, 2016	Jul. 25, 2014 item	Sep. 23, 2016 USD ($)	Jul. 31, 2009 item	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) item	Sep. 30, 2016 USD ($)
Loss contingencies
Claim amount	$ 280,000,000
General and administrative expenses							$ 182,679,000	$ 184,164,000	$ 487,287,000	$ 552,340,000
Vermont National Telephone Company
Loss contingencies
Loss Contingency Recovery Amount					$ 10,000,000,000
Falsely claimed bidding credit, percentage					25.00%
LightSquared transaction shareholder derivative actions
Loss contingencies
Number of shareholders who filed lawsuits | item									5
Number of Claims Asserted | item				5
LightSquared transaction shareholder derivative actions | Mr. Ergen
Loss contingencies
Number of Claims Asserted | item				3
LightSquared transaction shareholder derivative actions | Director Defendants
Loss contingencies
Number of Claims Asserted | item				1
Northstar Wireless or Northstar Spectrum | Vermont National Telephone Company
Loss contingencies
Bidding Credit					$ 3,300,000,000
Satellite transponder guarantees
Loss contingencies
Guarantees for payments							$ 143,000,000		$ 143,000,000
Technology Development Licensing
Loss contingencies
Number of reexamination petitions pending before patent and trademark office | item						2
Telemarketing Litigation [Member]
Loss contingencies
Period of injunctive relief sought from placing any outbound telemarketing calls to market or promote its goods or services			5 years						5 years
Lightsquared Harbinger Capital Partners LLC
Loss contingencies
Business days allowed to terminate existing agreements									3 days
Maximum | Vermont National Telephone Company
Loss contingencies
Claim amount					11,000
Minimum | Vermont National Telephone Company
Loss contingencies
Claim amount					$ 5,500
Telemarketing Litigation [Member]
Loss contingencies
Number of telemarketing calls | item									51,119
Litigation per call damages									$ 400
Dish Networks | Telemarketing Litigation [Member]
Loss contingencies
Litigation per call damages		$ 1,200