Accumulated Other Comprehensive Income (Loss) (Components of Other Comprehensive Income and Related Tax Effects) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Loss [Abstract]
Amortization of prior service credits and net actuarial loss, Before-Tax Amount	[1]	$ 229	$ 205	$ 687	$ 1,058
Proportionate share of Telesat other comprehensive income (loss), Before-Tax Amount	[2]	2,580	(1,318)	17,522
Other comprehensive income (loss), Before-Tax Amount		2,809	(1,113)	18,209	1,058
Amortization of prior service credits and net actuarial loss, Tax (Provision) Benefit		(88)	(76)	(261)	(394)
Proportionate share of Telesat other comprehensive income (loss), Tax (Provision) Benefit		(1,008)	491	(6,659)
Other comprehensive income, Tax (Provision) Benefit		(1,096)	415	(6,920)	(394)
Amortization of prior service credits and net actuarial gain (loss), Net-of-Tax Amount		141	129	426	664
Proportionate share of Telesat other comprehensive income (loss), Net-of-Tax Amount		1,572	(827)	10,863
Other comprehensive income (loss), Net-of-Tax Amount		$ 1,713	$ (698)	$ 11,289	$ 664

[1] Reclassifications are included in general and administrative expenses.

[2] See Note 6 for discussion of our share of Telesat other comprehensive income (loss).