Segment Information (Details 3) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Information on revenue, net of intersegment eliminations, by product group
Revenue	$ 99,207	$ 100,905	$ 96,187	$ 97,114	$ 99,631	$ 97,252	$ 96,784	$ 97,072	$ 393,413	$ 390,739	$ 391,150
Local voice and other retail services
Information on revenue, net of intersegment eliminations, by product group
Revenue									318,644	316,441	321,735
Wholesale carrier services and subsidies
Information on revenue, net of intersegment eliminations, by product group
Revenue									63,675	63,561	67,227
Data center colocation
Information on revenue, net of intersegment eliminations, by product group
Revenue									$ 11,094	10,737	$ 2,188
Proceeds from the sale of equipment										$ 400