Condensed Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Voting Common Stock [Member] Common Stock [Member]	Non-Voting Common Stock [Member] Common Stock [Member]	Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]	Total
Balance at Dec. 31, 2017	$ 216	$ 95	$ 1,019,988	$ (9,592)	$ (682,831)	$ (37,278)	$ 290,598
Balance, shares at Dec. 31, 2017	21,582	9,506		154
Net income (loss)					4,741
Other comprehensive income (loss)						7,772
Comprehensive income (loss)							12,513
Cumulative effect adjustment attributable to investment in Telesat					(22,107)		(22,107)
Balance at Jun. 30, 2018	$ 216	$ 95	1,019,988	$ (9,592)	(700,197)	(29,506)	281,004
Balance, shares at Jun. 30, 2018	21,582	9,506		154
Balance at Dec. 31, 2017	$ 216	$ 95	1,019,988	$ (9,592)	(682,831)	(37,278)	290,598
Balance, shares at Dec. 31, 2017	21,582	9,506		154
Net income (loss)							50,935
Other comprehensive income (loss)							2,362
Comprehensive income (loss)							53,297
Balance at Sep. 30, 2018	$ 216	$ 95	1,019,988	$ (9,592)	(654,003)	(34,916)	321,788
Balance, shares at Sep. 30, 2018	21,582	9,506		154
Balance at Dec. 31, 2017	$ 216	$ 95	1,019,988	$ (9,592)	(682,831)	(37,278)	290,598
Balance, shares at Dec. 31, 2017	21,582	9,506		154
Other comprehensive income (loss)						23,831
Balance at Dec. 31, 2018	$ 216	$ 95	1,019,988	$ (9,592)	(695,521)	(17,620)	297,566
Balance, shares at Dec. 31, 2018	21,582	9,506		154
Balance at Jun. 30, 2018	$ 216	$ 95	1,019,988	$ (9,592)	(700,197)	(29,506)	281,004
Balance, shares at Jun. 30, 2018	21,582	9,506		154
Net income (loss)					46,194		46,194
Other comprehensive income (loss)						(5,410)	(5,410)
Comprehensive income (loss)							40,784
Balance at Sep. 30, 2018	$ 216	$ 95	1,019,988	$ (9,592)	(654,003)	(34,916)	321,788
Balance, shares at Sep. 30, 2018	21,582	9,506		154
Net income (loss)					(41,321)
Other comprehensive income (loss)						21,469
Comprehensive income (loss)							(19,852)
Tax Cuts and Jobs Act, reclassification tax effect					4,173	(4,173)
Cumulative effect adjustment attributable to investment in Telesat					(4,370)		(4,370)
Balance at Dec. 31, 2018	$ 216	$ 95	1,019,988	$ (9,592)	(695,521)	(17,620)	297,566
Balance, shares at Dec. 31, 2018	21,582	9,506		154
Net income (loss)					76,743
Other comprehensive income (loss)						(13,052)
Comprehensive income (loss)							63,691
Balance at Jun. 30, 2019	$ 216	$ 95	1,019,988	$ (9,592)	(618,778)	(30,672)	361,257
Balance, shares at Jun. 30, 2019	21,582	9,506		154
Balance at Dec. 31, 2018	$ 216	$ 95	1,019,988	$ (9,592)	(695,521)	(17,620)	297,566
Balance, shares at Dec. 31, 2018	21,582	9,506		154
Net income (loss)							82,990
Other comprehensive income (loss)						(29,313)	(29,313)
Comprehensive income (loss)							53,677
Balance at Sep. 30, 2019	$ 216	$ 95	1,019,988	$ (9,592)	(612,531)	(46,933)	351,243
Balance, shares at Sep. 30, 2019	21,582	9,506		154
Balance at Jun. 30, 2019	$ 216	$ 95	1,019,988	$ (9,592)	(618,778)	(30,672)	361,257
Balance, shares at Jun. 30, 2019	21,582	9,506		154
Net income (loss)					6,247		6,247
Other comprehensive income (loss)						(16,261)	(16,261)
Comprehensive income (loss)							(10,014)
Balance at Sep. 30, 2019	$ 216	$ 95	$ 1,019,988	$ (9,592)	$ (612,531)	$ (46,933)	$ 351,243
Balance, shares at Sep. 30, 2019	21,582	9,506		154