Cash Flows (Summary Of Non-Cash Activities And Other Supplemental Data) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Significant Noncash Transactions [Line Items]
Deemed Capital (Distribution) Contribution Related To The Utilization Of Related Party Tax Losses By Company	$ (1,794)	$ 36,867	$ 52,824
Deemed Capital (Distribution) Contribution, Net, Related To Taxes	(1,148)	44,598	0
Capital Distribution Of Promissory Note Receivable To Related Party	0	(17,113)	0
Deemed Capital Distribution To Cablevision Related To Employee Benefit Plans As A Result Of The Distribution	0	(6,313)	0
Deemed Capital Distribution Related To Tax Credits Utilized By Related Party	0	(2,586)	0
Deemed Capital Distribution Associated With The Issuance Of Debt To Related Party	0	(1,250,000)	0
Deemed Capital Distribution Related To The Entities Transferred To Related Party	0	0	41,273
Deemed Capital Contribution Related To Allocation Of Related Party Share Based Compensation Expense	0	8,343	16,267
Leasehold Improvements Paid By Landlord	2,938	150	554
Capital Lease Obligations Incurred	1,398	39	(279)
Capital Expenditures Incurred but Not yet Paid	5,397	0	0
Cash Interest Paid, Continuing Operations	113,493	78,714	72,335
Income Taxes Paid, Net, Continuing Operations	40,522	11,569	5,217
Discontinued Operation or Asset Disposal [Member]
Other Significant Noncash Transactions [Line Items]
Deemed Capital Contribution Related To Allocation Of Related Party Share Based Compensation Expense	0	0	4,292
Income Taxes Refunded, Net, Discontinued Operations	$ 0	$ 0	$ (1)