Organization and Principal Business (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) segment	Jun. 30, 2020 USD ($)
Organization And Principal Business [Line Items]
Number of operating segment | segment			1
Telesat Canada [Member]
Organization And Principal Business [Line Items]
Economic interest in affiliate	62.60%		62.60%
Voting interest in affiliate	32.60%		32.60%
Common Control Reorganization [Member] | Other Expense [Member]
Organization And Principal Business [Line Items]
Transaction expenses	$ 2,000	$ 2,400	$ 4,300	$ 3,800
Common Control Reorganization [Member] | Plan [Member] | Public Sector Pension Investment Board [Member]
Organization And Principal Business [Line Items]
Loss contingency, contract breach	40,000		40,000
Common Control Reorganization [Member] | Plan [Member] | Minimum [Member] | Red Isle Private Investments Inc. [Member]
Organization And Principal Business [Line Items]
Loss contingency, contract termination	6,550		6,550
Common Control Reorganization [Member] | Plan [Member] | Maximum [Member] | Red Isle Private Investments Inc. [Member]
Organization And Principal Business [Line Items]
Loss contingency, contract termination	$ 22,910		$ 22,910