Note 2 - Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue Accounted for Under ASC 606		$ 51,382		$ 99,140
Revenue Accounted for Under Other Guidance		8,196		16,410
Operating revenues		59,578	$ 58,536	115,550	$ 115,267
Business and Wholesale Revenue, Business Broadband [Member]
Revenue Accounted for Under ASC 606		16,950		30,550
Revenue Accounted for Under Other Guidance
Operating revenues		16,950		30,550
Business and Wholesale Revenue, Business Voice and Other [Member]
Revenue Accounted for Under ASC 606		7,038		13,889
Revenue Accounted for Under Other Guidance
Operating revenues		7,038		13,889
Business and Wholesale Revenue, Managed IT Services [Member]
Revenue Accounted for Under ASC 606		1,191		2,456
Revenue Accounted for Under Other Guidance
Operating revenues		1,191		2,456
Business and Wholesale Revenue, Equipment Sales and Installations [Member]
Revenue Accounted for Under ASC 606		1,460		2,382
Revenue Accounted for Under Other Guidance
Operating revenues		1,460		2,382
Business and Wholesale Revenue, Wholesale Broadband [Member]
Revenue Accounted for Under ASC 606		7,795		15,851
Revenue Accounted for Under Other Guidance
Operating revenues		7,795		15,851
Business and Wholesale Revenue, Wholesale Voice and Other [Member]
Revenue Accounted for Under ASC 606		1,442		2,930
Revenue Accounted for Under Other Guidance
Operating revenues		1,442		2,930
Business and Wholesale Revenue, Operating Leases and Other Deferred Revenue [Member]
Revenue Accounted for Under ASC 606
Revenue Accounted for Under Other Guidance		1,602		3,183
Operating revenues		1,602		3,183
Business and Wholesale Revenue [Member]
Revenue Accounted for Under ASC 606		35,876		68,058
Revenue Accounted for Under Other Guidance		1,602		3,183
Operating revenues		37,478		71,241
Consumer Revenue, Broadband [Member]
Revenue Accounted for Under ASC 606		6,695		13,187
Revenue Accounted for Under Other Guidance
Operating revenues		6,695		13,187
Consumer Revenue, Voice and Other [Member]
Revenue Accounted for Under ASC 606		2,759		5,636
Revenue Accounted for Under Other Guidance
Operating revenues		2,759		5,636
Consumer Revenue [Member]
Revenue Accounted for Under ASC 606		9,454		18,823
Revenue Accounted for Under Other Guidance
Operating revenues		9,454		18,823
Regulatory Revenue, Access, Including Customer Ordered Service and Special Access [Member]
Revenue Accounted for Under ASC 606	[1]	6,052		12,259
Revenue Accounted for Under Other Guidance	[1]
Operating revenues	[1]	6,052		12,259
Regulatory Revenue, Access, Including Carrier of Last Resort and Carrier Common Line [Member]
Revenue Accounted for Under ASC 606	[2]
Revenue Accounted for Under Other Guidance	[2]	1,670		3,380
Operating revenues	[2]	1,670		3,380
Regulatory, High-cost Support [Member]
Revenue Accounted for Under ASC 606
Revenue Accounted for Under Other Guidance		4,924		9,847
Operating revenues		4,924		9,847
Regulatory Revenue [Member]
Revenue Accounted for Under ASC 606		6,052		12,259
Revenue Accounted for Under Other Guidance		6,594		13,227
Operating revenues		$ 12,646		$ 25,486

[1] Includes customer ordered service and special access.

[2] Includes carrier of last resort and carrier common line.