Related Party Transactions (Narrative) (Details) (USD $)	0 Months Ended		3 Months Ended		12 Months Ended
	Mar. 28, 2012	Apr. 11, 2011	Mar. 31, 2012 Y	Mar. 31, 2011	Dec. 31, 2011
Related Party Transaction [Line Items]
Revenue from related parties			$ 24,156,000	$ 42,251,000
Related party transaction, consulting fee			1,250,000	1,250,000
Common stock acquired by an unaffiliated third party			90.00%
Special cash distribution received from Telesat			375,809,000
Related party transaction, expenses from transactions with related party			14,200,000	33,900,000
Duration for shares to be paid, days			10
Telesat [Member]
Related Party Transaction [Line Items]
Percentage of ownership interest			64.00%
Amounts receivable by SS/L from Affiliate Telesat related to satellite construction contracts			10,700,000		4,600,000
Related party transaction, date			Oct. 31, 2007
Consulting Agreement, term			7
Consulting Agreement, additional renewal term			7
Revenue from related parties			24,211,000	42,238,000
Consulting Agreement, annual fee			5,000,000
Related party transaction, rate			7.00%
Long-term receivable related to Consulting Agreement			20,700,000		20,700,000
Payment received from Telesat related to Consulting Agreement			1,600,000
Indemnification liabilities recognized with related party affiliate Telesat			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	376,000,000
Premium from sale of Loral Payload		13,000,000
Reimbursement of costs under payload and related agreements					48,200,000
Payments to affiliates		1,400,000
Liability for ChinaSat future use of transponders			3,100,000		3,700,000
Interest expense on ChinaSat liability			100,000	100,000
Payments to related party pursuant to the ChinaSat agreement			500,000
ViaSat [Member]
Related Party Transaction [Line Items]
Revenue from related parties			200,000	4,700,000
Payment of launch and associated services actual costs by parent, percentage			15.00%
Payments to affiliates		3,900,000
XTAR [Member]
Related Party Transaction [Line Items]
Percentage of ownership interest			56.00%
Management fee charged as a percentage of revenue			3.70%
Management fees due from joint venture XTAR			$ 4,800,000		$ 4,200,000
MHR Funds [Member]
Related Party Transaction [Line Items]
Percentage of outstanding voting common stock			38.50%		38.60%
Percentage of combined ownership of voting and non-voting common stock			57.50%		57.70%
Telesat [Member]
Related Party Transaction [Line Items]
Percentage of ownership interest			64.00%