Accumulated Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Loss) (Details) (USD $)	3 Months Ended		9 Months Ended			12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012	Dec. 31, 2012
Accumulated other comprehensive income (loss), Beginning balance			$ (37,394,000)		$ (154,475,000)	$ (154,475,000)
Other comprehensive income (loss) before reclassification			(402,000)			2,446,000
Amounts reclassified from accumulated other comprehensive income (loss)			2,791,000			114,635,000
Net current-period other comprehensive income (loss)	526,000	2,285,000	2,389,000		7,496,000	117,081,000
Accumulated other comprehensive income (loss), Ending balance	(35,005,000)		(35,005,000)			(37,394,000)
Derivatives [Member]
Accumulated other comprehensive income (loss), Beginning balance					(1,306,000)	(1,306,000)
Other comprehensive income (loss) before reclassification						(415,000)
Amounts reclassified from accumulated other comprehensive income (loss)						1,721,000
Net current-period other comprehensive income (loss)						1,306,000
Unrealized Gains (losses) on Investments [Member]
Accumulated other comprehensive income (loss), Beginning balance					580,000	580,000
Other comprehensive income (loss) before reclassification						(120,000)
Amounts reclassified from accumulated other comprehensive income (loss)						(460,000)
Net current-period other comprehensive income (loss)						(580,000)
Postretirement Benefits [Member]
Accumulated other comprehensive income (loss), Beginning balance			(17,653,000)		(132,695,000)	(132,695,000)
Other comprehensive income (loss) before reclassification			(319,000)			1,668,000
Amounts reclassified from accumulated other comprehensive income (loss)			2,791,000	[1]		113,374,000
Net current-period other comprehensive income (loss)			2,472,000			115,042,000
Accumulated other comprehensive income (loss), Ending balance	(15,181,000)		(15,181,000)			(17,653,000)
Proportionate Share of Telesat Other Comprehensive Loss [Member]
Accumulated other comprehensive income (loss), Beginning balance			(19,741,000)		(21,054,000)	(21,054,000)
Other comprehensive income (loss) before reclassification			(83,000)			1,313,000
Net current-period other comprehensive income (loss)			(83,000)			1,313,000
Accumulated other comprehensive income (loss), Ending balance	(19,824,000)		(19,824,000)			(19,741,000)
Accumulated Other Comprehensive Loss [Member]
Net current-period other comprehensive income (loss)			2,389,000			117,081,000
General Administrative Expenses [Member]
Reclassification from postretirement benefits accumulated other comprehensive income (loss)			4,600,000
Income Tax Provision Benefit [Member]
Reclassification from postretirement benefits accumulated other comprehensive income (loss)			$ (1,800,000)

[1] Reclassification from postretirement benefits accumulated other comprehensive loss comprises $4.6 million included in general and administrative expenses and $1.8 million tax benefit thereon included in income tax benefit in our condensed consolidated statement of operations.