Accumulated Other Comprehensive Income (Components Of Other Comprehensive Income And Related Tax Effects) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			12 Months Ended
	Mar. 31, 2013		Mar. 31, 2012	Dec. 31, 2012
Accumulated Other Comprehensive Income [Abstract]
Amortization of prior service credits and net actuarial loss, Before-Tax Amount	$ 1,501		$ 2,012
Proportionate share of Telesat Holdco other comprehensive (loss)income, Before-Tax Amount	718		908
Unrealized loss on foreign currency hedges, Before-Tax Amount			(1,677)
Less: reclassification adjustment for loss included in net income from discontinued operations, Before-Tax Amount			3,277
Net unrealized gain (loss) on derivatives, Before-Tax Amount			1,600
Unrealized loss on available-for-sale securities, Before-Tax Amount			157
Other comprehensive income, Before-Tax Amount	2,219		4,677
Amortization of prior service credits and net actuarial loss, Tax (Expense) Benefit	(573)		(808)
Proportionate share of Telesat Holdco other comprehensive (loss) income, Tax (Expense) Benefit	(274)		(365)
Unrealized loss on foreign currency hedges, Tax (Expense) Benefit			675
Less: reclassification adjustment for loss included in net income from discontinued operations, Tax (Expense) Benefit			(1,319)
Net unrealized gain on derivatives , Tax (Expense) Benefit			(644)
Unrealized loss on available-for-sale securities , Tax (Expense) Benefit			(63)
Other comprehensive income (loss), Tax (Expense) Benefit	(847)		(1,880)
Amortization of prior service credits and net actuarial loss, Net-of Tax Amount	928	[1]	1,204	113,374
Proportionate share of Telesat Holdco other comprehensive income (loss)	444		543
Unrealized loss on foreign currency hedges, Net-of Tax Amount			(1,002)	(415)
Less: reclassification adjustment for loss included in net income from discontinued operations, Net-of Tax Amount			1,958	1,721
Net unrealized gain (loss) on derivatives, Net-of Tax Amount			956	1,306
Unrealized loss on available-for-sale securities, Net-of Tax Amount			94	(120)
Other comprehensive income, Net-of Tax Amount	$ 1,372		$ 2,797	$ 117,081

[1] Reclassification from postretirement benefits accumulated other comprehensive loss comprises $1.5 million included in general and administrative expenses and $0.6 million tax benefit thereon included in income tax provision in our condensed consolidated statement of operations.