Related Party Transactions (Narrative) (Detail) (USD $)	1 Months Ended			3 Months Ended		9 Months Ended		12 Months Ended
	Jul. 05, 2012	Mar. 28, 2012	Apr. 11, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Satellite construction contracts
Common stock acquired by an unaffiliated third party						90.00%
Duration for shares to be paid, days						10 days
Special cash distribution received from Telesat						$ 420,199,000
Revenue from related parties				9,363,000	32,770,000	55,946,000	108,615,000
Gain on transactions with affiliate					6,900,000
Gain (loss) on transaction with subsidiary classified as discontinued operations							1,800,000
Proceeds from cumulative intercompany profit						13,000,000
Related party transaction, expenses from transactions with related party				5,500,000	29,600,000	29,900,000	98,100,000
Telesat [Member]
Satellite construction contracts
Percentage of ownership interest				64.00%		64.00%
Amounts receivable by SS\L from affiliate Telesat related to satellite construction contracts				2,200,000		2,200,000		4,600,000
Related party transaction, date						Oct. 31, 2007
Consulting agreement, term						7 years
Consulting agreement, additional renewal term						7 years
Consulting agreement, annual fee						5,000,000
Related party transaction rate						7.00%
Related party transaction, consulting fee				1,250,000	1,250,000	3,750,000	3,750,000
Long-term receivable related to consulting agreement				24,000,000		24,000,000		20,700,000
Payment received from Telesat related to consulting agreement						1,600,000	3,200,000
Indemnification liabilities recognized with related party affiliate Telesat				500,000		500,000		500,000
Indemnification assets with related party affiliate Telesat						2,600,000		2,600,000
Tax recovery benefit included in long-term liabilities						2,100,000		2,100,000
Special cash distribution received from Telesat	44,000,000	376,000,000
Payment of launch and associated services actual costs by parent, percentage						15.00%
Revenue from related parties				9,383,000	32,754,000	56,095,000	108,579,000
Premium from sale of Loral Payload			13,000,000
Reimbursement of costs under payload and related agreements			48,200,000
Duration of contract assigned to Telesat						15 years
Payments to affiliates			1,400,000
Liability for ChinaSat future use of transponders				1,900,000		1,900,000		3,700,000
Interest expense on ChinaSat liability				100,000	100,000	200,000	400,000
Payments to related party pursuant to the ChinaSat agreement						2,000,000
Viasat
Satellite construction contracts
Revenue from related parties				(100,000)	2,400,000	400,000	7,800,000
Payments to affiliates			3,900,000
Xtar
Satellite construction contracts
Percentage of ownership interest				56.00%		56.00%
Management fee charged as a percentage of revenue						3.70%
Management fees due from joint venture XTAR				$ 5,100,000		$ 5,100,000		$ 4,200,000
MHR Funds
Satellite construction contracts
Percentage of outstanding voting common stock						38.30%		38.60%
Percentage of combined ownership of voting and non-voting common stock				57.40%		57.40%		57.70%