Related Party Transactions (Narrative) (Details) - USD ($)		3 Months Ended			12 Months Ended
	Jul. 02, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2013	Dec. 31, 2020	Jul. 01, 2020	Dec. 31, 2019
Related Party Transaction [Line Items]
Due to affiliate		$ 198,000			$ 98,000
Amounts due under the transaction		$ 59,000			$ 88,000
Transaction, Consulting Agreement [Member] | Director [Member]
Related Party Transaction [Line Items]
Related party transaction, start date		Dec. 14, 2012
Transaction fee		$ 360,000	$ 360,000
Transaction income during the period		11,250	11,250
Monthly Fee [Member] | Transaction, Consulting Agreement [Member] | Director [Member]
Related Party Transaction [Line Items]
Transaction fee		$ 120,000
Telesat Canada [Member]
Related Party Transaction [Line Items]
Economic interest in affiliate		62.60%			62.60%
Voting interest in affiliate		32.60%			32.60%
Common stock, percentage acquired by an unaffiliated third party		90.00%
Duration for shares to be paid, days		10 days
Telesat Canada [Member] | Transaction, Consulting Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, start date		Oct. 31, 2007
Consulting agreement term		seven-years with an automatic renewal for an additional seven-year
Transaction income during the period		$ 1,250,000	1,250,000
Transaction payments received during the period		1,200,000	$ 1,200,000
Telesat Canada [Member] | Annual Fee [Member] | Transaction, Consulting Agreement [Member]
Related Party Transaction [Line Items]
Transaction fee		5,000,000.0
Telesat Canada [Member] | Annual Fee [Member] | Transaction Participation In Welfare Plans Administrative Fee [Member]
Related Party Transaction [Line Items]
Due to affiliate		200,000			$ 100,000
Transaction fee		100,000
Telesat Canada [Member] | Years 2003 to 2006 [Member] | Brazil [Member]
Related Party Transaction [Line Items]
Tax assessment imposed audit		$ 600,000
XTAR, LLC [Member]
Related Party Transaction [Line Items]
Percentage of ownership interest		56.00%
XTAR, LLC [Member] | Transaction, Management Agreement [Member]
Related Party Transaction [Line Items]
Due from affiliates		$ 100,000			$ 100,000
Amount due to Loral under the Loral Management Agreement						$ 6,600,000	$ 6,600,000
Increase (decrease) in due from affiliates	$ (5,900,000)
Allowance for doubtful receivable						$ 6,600,000
Management fee charged as a percentage of revenue				3.70%
Common Control Reorganization [Member] | Plan [Member]
Related Party Transaction [Line Items]
Counterparties indemnifying		Loral, Telesat Corporation and Telesat CanHoldco
Counterparty indemnified		Public Sector Pension Investment Board
Transaction indemnities		(a) certain losses and litigation proceedings related to the Transaction, (b) certain out-of-pocket expenses of Loral after the Closing and (c) certain tax matters. This indemnification will be (i) independent of the accuracy of the underlying representations and warranties, (ii) in the case of the tax indemnification, subject to a cap of $50 million and (iii) subject to additional, customary limitations.
Tax indemnification - maximum		$ 50,000,000
Series B Preferred Stock [Member]
Related Party Transaction [Line Items]
Preferred stock, shares issued		5			5
Red Isle Private Investments Inc. [Member] | Common Control Reorganization [Member] | Plan [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Description of Transaction		if such payment is less than $7 million due to a lack of available cash, Telesat Partnership will be required to pay the balance of such unpaid amount to Red Isle no later than 35 trading days following consummation of the Transaction
Transaction fee		$ 7,000,000
Red Isle Private Investments Inc. [Member] | Minimum [Member] | Common Control Reorganization [Member] | Plan [Member]
Related Party Transaction [Line Items]
Loss contingency, contract termination		6,550,000
Red Isle Private Investments Inc. [Member] | Maximum [Member] | Common Control Reorganization [Member] | Plan [Member]
Related Party Transaction [Line Items]
Loss contingency, contract termination		22,910,000
Public Sector Pension Investment Board [Member] | Common Control Reorganization [Member] | Plan [Member]
Related Party Transaction [Line Items]
Loss contingency, contract breach		$ 40,000,000
MHR Funds [Member]
Related Party Transaction [Line Items]
Percentage of outstanding voting common stock		39.90%			39.90%
Percentage of combined ownership of voting and non-voting common stock		58.40%			58.40%
MHR Funds [Member] | Maximum [Member] | Additional Voting Common Stock [Member]
Related Party Transaction [Line Items]
Percentage of outstanding voting common stock		6.00%