Organization and Principal Business (Narrative) (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)
Organization And Principal Business [Line Items]
Number of operating segment | segment	1
Telesat Holdings Inc [Member]
Organization And Principal Business [Line Items]
Economic interest in affiliate	62.60%
Voting interest in affiliate	32.60%
Common Control Reorganization [Member] | Other Expense [Member]
Organization And Principal Business [Line Items]
Transaction expenses	$ 10,200,000	$ 4,000,000.0
Common Control Reorganization [Member] | Plan [Member] | Public Sector Pension Investment Board [Member]
Organization And Principal Business [Line Items]
Loss contingency, contract breach	40,000,000
Common Control Reorganization [Member] | Plan [Member] | Minimum [Member] | Red Isle Private Investments Inc. [Member]
Organization And Principal Business [Line Items]
Loss contingency, contract termination	6,550,000
Common Control Reorganization [Member] | Plan [Member] | Maximum [Member] | Red Isle Private Investments Inc. [Member]
Organization And Principal Business [Line Items]
Loss contingency, contract termination	$ 22,910,000