Commitments and Contingencies (Details) $ in Thousands													1 Months Ended	3 Months Ended		12 Months Ended	147 Months Ended
	Apr. 01, 2020	Oct. 22, 2019 USD ($)	Jul. 26, 2019 USD ($) item employee	Jun. 07, 2018 USD ($)	Jun. 06, 2018	May 11, 2017 USD ($)	Jul. 01, 2016 USD ($)	Aug. 18, 2015 USD ($)	Apr. 29, 2014 USD ($) segment	Oct. 29, 2013	Mar. 09, 2012	Mar. 09, 2012 USD ($)	Jan. 31, 2017	Mar. 31, 2020 USD ($) item store	Mar. 31, 2018 USD ($) item	Dec. 31, 2008 USD ($)	Mar. 31, 2020 USD ($) item	Dec. 31, 2019 USD ($)	Apr. 13, 2017 USD ($) item
Spectrum Investments
Payment to acquire certain wireless licenses and related assets																	$ 21,000,000
FCC authorizations														$ 26,008,056			26,008,056	$ 25,779,503
Period in which at least 20% of population served to avoid payment of damages			3 years
Number of spectrum bands | item			4
Impairment of long-lived assets														356,418
Commitments relating to AWS-3 Auction
Noncontrolling Interest in Variable Interest Entity														10,000,000			10,000,000
Capitalized interest on FCC authorizations [Member]
Spectrum Investments
FCC authorizations														$ 5,000,000			5,000,000
Asset Purchase Agreement
Sprint Asset Acquisition
Purchase price			$ 1,400,000
Period after provisioning new or existing customers of prepaid business			15 days
Period after final judgment			5 days
Number of employees expected to transfer | employee			480
Right to terminate agreement, period			12 months
Right to terminate agreement after closing of merger period			90 days
Sellers right to terminate agreement, period			90 days
Spectrum Purchase Agreement
Spectrum Investments
Period of spectrum divestiture extend														60 days
Sprint Asset Acquisition
Purchase price			$ 3,590,000
Option Agreement
Spectrum Investments
Period after closing of prepaid business sale, transfer asset request is admissible			1 year
Period within closing of prepaid business sale, required to offer nationwide postpaid retail mobile wireless service			1 year
Period within entry of final judgment	5 years		90 days
Damages To Be Paid In Case Of Breach Of Agreement			$ 360,000
Percentage of purchase price			10.00%
Percentage of population served			20.00%
Period in which at least 20% of population served to avoid payment of damages			3 years
Status of negotiation period			90 days
Threshold period for involvement of DOJ			180 days
Period obliged to provide DOJ with description of deployment efforts			180 days
Term of final judgement from the date of its entry with the District Court.	7 years		7 years
Term of final judgement if DOJ gives notice	5 years
Spectrum Lease Period			6 years
Number of spectrum bands | item			4
MVDDS Licenses
Spectrum Investments
Number of geographical license areas | item														82
MVDDS Licenses | Maximum
Spectrum Investments
Number of geographical license areas | item														214
LMDS Licenses
Spectrum Investments
Number Of Markets | item														4
Wireless
Spectrum Investments
Payment to acquire certain wireless licenses and related assets																	11,000,000
H Block Licenses
Spectrum Investments
Payment to acquire certain wireless licenses and related assets									$ 1,672,000
Number of wireless spectrum licenses | segment									176
H Block Licenses | Minimum
Spectrum Investments
Final Build-out Requirement (as a percent)														75.00%
700 MHz Licenses
Spectrum Investments
Payment to acquire certain wireless licenses and related assets																$ 712,000
Modified 700 MHz Final Build-out Requirement (as a percent)										70.00%
700 MHz Licenses | Maximum
Spectrum Investments
Percent of coverage on available licensed geographic areas			70.00%
700 MHz Licenses | Minimum
Spectrum Investments
Percent of coverage on available licensed geographic areas			20.00%
600 MHz Licenses
Spectrum Investments
Number of wireless spectrum licenses | item																			486
Build-out requirement accelerated period													2 years
Aggregate Bid Price																			$ 6,211,000
Licenses Renewal Period														39 months
600 MHz Licenses | Maximum
Spectrum Investments
Percent of coverage on available licensed geographic areas			75.00%											75.00%
600 MHz Licenses | Minimum
Spectrum Investments
Percent of coverage on available licensed geographic areas			70.00%											40.00%
28 GHz and 24 GHz Licenses
Spectrum Investments
Aggregate Bid Price														$ 15,000			$ 15,000
37 Ghz, 39 Ghz and 47 Ghz Licenses
Spectrum Investments
Number of wireless spectrum licenses | item														2,651			2,651
Aggregate Bid Price														$ 203,000			$ 203,000
37 Ghz And 39 Ghz Licenses
Spectrum Investments
Number of wireless spectrum licenses | item														50			50
47 Ghz Licenses
Spectrum Investments
Number of wireless spectrum licenses | item														2,601			2,601
AWS H Block licenses | Maximum
Spectrum Investments
Percent of coverage on available licensed geographic areas			70.00%
AWS H Block licenses | Minimum
Spectrum Investments
Percent of coverage on available licensed geographic areas			20.00%
AWS-4 Satellites | Maximum
Spectrum Investments
Percent of coverage on available licensed geographic areas			70.00%
AWS-4 Satellites | Minimum
Spectrum Investments
Percent of coverage on available licensed geographic areas			20.00%
DBSD North America and TerreStar Transactions | Wireless
Spectrum Investments
Purchase price												$ 2,860,000
AWS-4 Final Build-out Requirement (as a percent)														70.00%
DBSD North America and TerreStar Transactions | AWS-4 Satellites
Spectrum Investments
Ownership percentage											100.00%
NTM Network | Spectrum Purchase Agreement
Spectrum Investments
Spectrum lease back period														2 years
Northstar Spectrum And SNR Holdco
Spectrum Investments
Ownership interest														$ 578,000			$ 578,000
Commitments relating to AWS-3 Auction
Noncontrolling Interest in Variable Interest Entity														$ 10,000,000			$ 10,000,000
Northstar Spectrum And SNR Holdco | American III
Spectrum Investments
Number of wireless spectrum licenses | item														244			244
Northstar Spectrum And SNR Holdco | AWS-3 Licenses
Spectrum Investments
Interim Build-out Requirement (as a percent)														40.00%
Final Build-out Requirement (as a percent)														75.00%
Accelerated period to meet Final Build-Out Requirement on failure to meet Interim Build-Out Requirement														2 years
Northstar Spectrum And SNR Holdco | SNR Licenses
Commitments relating to AWS-3 Auction
Percentage of bidding credit								25.00%
Northstar Wireless or Northstar Spectrum
Spectrum Investments
Interim payment percentage														15.00%
Re-Auction payment														$ 1,892,000
Overpayment Of Interim Payment														$ 334,000
Northstar Wireless or Northstar Spectrum | Preferred Class A
Spectrum Investments
Ownership percentage														100.00%
Northstar Wireless or Northstar Spectrum | Class B common stock
Spectrum Investments
Ownership percentage														85.00%
Commitments relating to AWS-3 Auction
Controlling interest owned by other companies														15.00%
Northstar Wireless or Northstar Spectrum | Northstar Manager LLC
Commitments relating to AWS-3 Auction
Equity contribution															$ 133,000
Northstar Wireless or Northstar Spectrum | American II
Spectrum Investments
Loan made														$ 69,000
Window of days for management to put its interest				90 days	30 days
Additional days allowed for management to put its interest				90 days
Commitments relating to AWS-3 Auction
Equity contribution															7,621,000
Northstar Wireless or Northstar Spectrum | American II | Maximum
Spectrum Investments
Preferred stock quarterly distribution (as a percent)				12.00%
Northstar Wireless or Northstar Spectrum | American II | Minimum
Spectrum Investments
Preferred stock quarterly distribution (as a percent)				8.00%
Northstar Wireless or Northstar Spectrum | AWS 3 Auction
Spectrum Investments
Interim Payment														$ 334,000
Interim payment percentage														15.00%
Northstar Wireless or Northstar Spectrum | Northstar Licenses
Spectrum Investments
Number of wireless spectrum licenses | item														261			261
Commitments relating to AWS-3 Auction
Gross winning bids														$ 5,619,000
Bidding credit value								$ 1,961,000
Northstar Wireless or Northstar Spectrum | AWS-3 Licenses
Spectrum Investments
Non-payment gross winning bids														2,226,000			$ 2,226,000
Commitments relating to AWS-3 Auction
Gross winning bids														$ 7,845,000
Percentage of bidding credit														25.00%
Net winning bid														$ 5,884,000
Number of licenses returned | item														84
SNR Wireless or SNR Wireless Holdco
Spectrum Investments
Re-Auction payment														$ 1,029,000
Overpayment Of Interim Payment														$ 182,000
SNR Wireless or SNR Wireless Holdco | Preferred Class A
Spectrum Investments
Ownership percentage														100.00%
SNR Wireless or SNR Wireless Holdco | Class B common stock
Spectrum Investments
Ownership percentage														85.00%
Commitments relating to AWS-3 Auction
Controlling interest owned by other companies														15.00%
SNR Wireless or SNR Wireless Holdco | Maximum
Spectrum Investments
Preferred stock quarterly distribution (as a percent)				12.00%
SNR Wireless or SNR Wireless Holdco | Minimum
Spectrum Investments
Preferred stock quarterly distribution (as a percent)				8.00%
SNR Wireless or SNR Wireless Holdco | SNR Wireless Management LLC
Commitments relating to AWS-3 Auction
Equity contribution															93,000
SNR Wireless or SNR Wireless Holdco | American III
Spectrum Investments
Loan made														$ 344,000
Debt outstanding amount															5,065,000
Principal amount of debt															500,000
Window of days for management to put its interest				90 days	30 days
Additional days allowed for management to put its interest				90 days
Commitments relating to AWS-3 Auction
Equity contribution															$ 5,590,000
Gross winning bids														$ 4,271,000
SNR Wireless or SNR Wireless Holdco | American III | Preferred Class A
Spectrum Investments
Number shares issued in conversion | item															5,065,415
Preferred stock quarterly distribution (as a percent)															12.00%
SNR Wireless or SNR Wireless Holdco | American III | Maximum
Spectrum Investments
Interest rate (as a percent)															12.00%
SNR Wireless or SNR Wireless Holdco | American III | Minimum
Spectrum Investments
Interest rate (as a percent)														6.00%			6.00%
SNR Wireless or SNR Wireless Holdco | AWS 3 Auction
Spectrum Investments
Non-payment gross winning bids														$ 1,211,000			$ 1,211,000
Commitments relating to AWS-3 Auction
Gross winning bids														5,482,000
Net winning bid														4,112,000
Bid withdrawal payment														8,000
SNR Wireless or SNR Wireless Holdco | AWS-3 Licenses
Spectrum Investments
Non-payment gross winning bids														$ 1,211,000			1,211,000
SNR Wireless or SNR Wireless Holdco | AWS-3 Licenses | SNR Wireless Management LLC
Spectrum Investments
Interim payment percentage														15.00%
SNR Wireless or SNR Wireless Holdco | SNR Licenses
Spectrum Investments
Interim Payment														$ 182,000
Non-payment gross winning bids														1,211,000			1,211,000
Additional Bid Withdrawal Payment														3,000
Commitments relating to AWS-3 Auction
Bidding credit value								$ 1,370,000
Prior Arrangement | Northstar Licenses
Spectrum Investments
Non-payment gross winning bids														$ 2,226,000			$ 2,226,000
Prior Arrangement | Northstar Spectrum And SNR Holdco | SNR Licenses
Commitments relating to AWS-3 Auction
Number of licenses returned | item														113
Northstar Operative Agreement | Northstar Spectrum And SNR Holdco | American II
Spectrum Investments
Debt outstanding amount															$ 6,870,000
Northstar Operative Agreement | Northstar Wireless or Northstar Spectrum | American II
Spectrum Investments
Principal amount of debt															$ 500,000
Loan balance maturity period				10 years	7 years
Removal of consent for unsecured financing and equipment financing				$ 25,000
Northstar Operative Agreement | Northstar Wireless or Northstar Spectrum | American II | Preferred Class A
Spectrum Investments
Number shares issued in conversion | item															6,870,493
Preferred stock quarterly distribution (as a percent)															12.00%
Northstar Operative Agreement | Northstar Wireless or Northstar Spectrum | American II | Maximum
Spectrum Investments
Interest rate (as a percent)															12.00%
Northstar Operative Agreement | Northstar Wireless or Northstar Spectrum | American II | Minimum
Spectrum Investments
Interest rate (as a percent)															6.00%
SNR Operative Agreement | SNR Wireless or SNR Wireless Holdco | American III
Spectrum Investments
Loan balance maturity period				10 years	7 years
Removal of consent for unsecured financing and equipment financing				$ 25,000
Spectrum Purchase Agreement
Spectrum Investments
Period within which divesture to be completed after receipt of FCC approval														3 years
Threshold divesture deadline extension period														5 days
Spectrum lease back period														3 years
per-Pop rate														$ 68,000
Decrease in purchase price due to failure to complete rebanding activities														72,000
Damages sought value in case of breach of agreement														$ 72,000
Master Network Service Agreement
Spectrum Investments
Service receipt period														2 years
Maximum Permitted Ownership Percent														50.00%
service pass through costs and out of pocket expenses charging period														36 months
Threshold Ownership Percentage Of Not Permitted Owners														50.00%
Percentage Of Wireless Communication Business Assets Are Sold														50.00%
Percentage Of Voting Power Or Economic Value Held By Restricted Persons														50.00%
Provision For New User After Change Of Control														6 months
Option Agreement
Spectrum Investments
Number of cell sites | item														20,000
Number of retail stores | store														400
Period in which cell sites are scheduled to be decommissioned														5 years
Option agreement term														5 years
Period after closing of prepaid business sale, transfer asset request is admissible			1 year
Period within closing of prepaid business sale, required to offer nationwide postpaid retail mobile wireless service			1 year
Damages To Be Paid In Case Of Breach Of Agreement			$ 360,000
Percentage of purchase price			10.00%
Percentage of population served			20.00%
Status of negotiation period			90 days
Threshold period for involvement of DOJ			180 days
Period obliged to provide DOJ with description of deployment efforts			180 days
Spectrum Lease Period			6 years
Option Agreement | AWS-4 Satellites
Spectrum Investments
Damages To Be Paid In Case Of Breach Of Agreement			$ 2,200,000
FCC Wireless Bureau | Auction 1000
Spectrum Investments
Payment to acquire certain wireless licenses and related assets							$ 1,500,000
Payment of remaining balance of winning bid						$ 4,711,000
FCC Wireless Bureau | Auction 103
Spectrum Investments
Payment to acquire certain wireless licenses and related assets		$ 68,000
Payment of remaining balance of winning bid		$ 135,000
NBIoT capitalized costs
Spectrum Investments
Impairment of long-lived assets														$ 253,000
SNR Credit Agreement | SNR Wireless or SNR Wireless Holdco
Spectrum Investments
Loan made															$ 500,000
Northstar Credit Agreement | Northstar Wireless or Northstar Spectrum | American II
Spectrum Investments
Loan made															$ 500,000