Property, Plant And Equipment (Schedule Of Property, Plant And Equipment) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 79,799	$ 84,848
Less: Accumulated depreciation	63,353	59,423
Property, plant and equipment, net	16,446	25,425
Land, Buildings And Other Support Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	10,647	10,908
Network Communications Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	35,183	36,187
Telephone Plant [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	28,030	30,571
Online Plant [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	5,905	6,885
Plant In Service [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	79,765	84,551
Plant Under Construction [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 34	$ 297