Investments in Affiliates (Equity Method Investment, Summarized Financial Data) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Telesat Holdings Inc [Member]
Statement of Operations Data:
Revenues	$ 170,151	$ 172,336	$ 514,800	$ 522,849
Operating expenses	(33,770)	(34,626)	(111,919)	(102,853)
Depreciation, amortization and stock-based compensation	(49,741)	(49,816)	(145,875)	(147,207)
Gain (loss) on disposition of long lived asset	(204)	(19)	(220)	(1,932)
Operating income (loss)	86,436	87,875	256,786	270,857
Interest expense	(37,901)	(34,311)	(111,765)	(104,662)
Foreign exchange gains (losses)	103,099	(33,639)	193,259	120,632
Gains (losses) on financial instruments	(6,542)	2,587	(17,471)	(3,364)
Other income (expense)	1,200	1,518	348	3,301
Income tax provision	(16,114)	(13,556)	(35,571)	(39,625)
Net income (loss)	130,178	10,474	285,586	247,139
Current assets	373,975		373,975		$ 678,361
Total assets	4,050,520		4,050,520		4,194,006
Current liabilities	128,247		128,247		154,173
Long-term debt, including current portion	2,832,685		2,832,685		2,877,950
Total liabilities	3,549,488		3,549,488		3,597,056
Shareholders' equity/Members' equity (deficit)	501,032		501,032		596,950
XTAR, LLC [Member]
Statement of Operations Data:
Revenues	4,236	3,815	11,759	14,115
Operating expenses	(3,871)	(1,882)	(11,816)	(18,075)
Depreciation, amortization and stock-based compensation	(1,658)	(2,191)	(4,975)	(6,575)
Operating income (loss)	(1,293)	(258)	(5,032)	(10,535)
Net income (loss)	(2,786)	$ (706)	(9,488)	$ (12,745)
Current assets	5,639		5,639		6,364
Total assets	30,309		30,309		36,008
Current liabilities	59,140		59,140		53,795
Total liabilities	76,813		76,813		75,395
Shareholders' equity/Members' equity (deficit)	$ (46,504)		$ (46,504)		$ (39,387)