Investments in Affiliates (Equity Method Investment, Summarized Financial Data) (Details) - Telesat Canada [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Summary Financial Data:
Revenues	$ 149,761	$ 172,995	$ 308,326	$ 340,639
Operating expenses	(34,540)	(32,929)	(70,395)	(73,498)
Depreciation and amortization	(43,031)	(51,569)	(88,448)	(102,777)
Other operating income (expense)	11	(10)	(156)	(65)
Operating income	72,201	88,487	149,327	164,299
Interest expense	(36,685)	(46,492)	(78,232)	(93,335)
Foreign exchange (loss) gain	98,313	45,946	(123,330)	98,415
Gain (loss) on financial instruments	(4,884)	(21,263)	(11,889)	(36,375)
Other income (expense)	1,874	4,272	5,952	8,106
Income tax benefit (provision)	(10,138)	(6,481)	(9,456)	(11,036)
Net (loss) income	120,681	$ 64,469	(67,628)	$ 130,074
Current assets	965,015		965,015		$ 877,294
Total assets	4,016,324		4,016,324		4,130,337
Current liabilities	127,735		127,735		124,217
Long-term debt, including current portion	2,829,344		2,829,344		2,836,700
Total liabilities	3,443,905		3,443,905		3,504,594
Shareholders' equity	$ 572,419		$ 572,419		$ 625,743