Cash Flows (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2011	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Dec. 31, 2010
Cash Flows [Line Items]
Principal amount of promissory note						$ 0
Interest rate			8.625%
Interest income	0			120
Distribution of promissory note including accrued and unpaid interest			0	17,113
Net receivable		876
Increase in related parties employee related liabilities		7,478
Capital distribution related to benefit accounts		6,602
Unfunded liability in cash balance pension plan		6,193
Increase in due to related parties		6,742
Debt distributed to related party			0	1,250,000	1,250,000
Increase in income taxes paid, after utilization of NOLs			11,603
Cablevision Excess Savings Plan [Member]
Cash Flows [Line Items]
Increase in related parties employee related liabilities		(3,616)
Cablevision Excess Cash Balance Pension Plan [Member]
Cash Flows [Line Items]
Increase in related parties employee related liabilities		$ (3,862)