Orange County-Poughkeepsie Limited Partnership (Summarized O-P Income Statement Information) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011		Dec. 31, 2010
Schedule of Equity Method Investments [Line Items]
Company share	$ 11,021	$ 7,898		$ 12,578
Period of the O-P operating as wholesale business	5 months
Period of the O-P operating as retail business	7 months
O-P [Member]
Schedule of Equity Method Investments [Line Items]
Net sales	310,416	273,340	[1]	187,985
Cellular service cost	151,712	122,142	[1]	23,859
Operating expenses	81,152	53,832	[1]	10,035
Operating income	77,552	97,366	[1]	154,091
Other income	14	40	[1]	1,034
Net income	77,566	97,406	[1]	155,125
Company share	$ 6,290	$ 7,898	[1]	$ 12,578

[1] The twelve months ended December 31, 2011 income statement represents five months of the O-P operating as a wholesale business and seven months of the O-P operating as a retail business in accordance with Amendment 6 to the O-P Limited Partnership Agreement effective May 1, 2011.