Note 2 - Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Revenue Accounted for Under ASC 606		$ 50,224	$ 49,042
Revenue Accounted for Under Other Guidance		8,042	7,867
Total Revenue		58,266	56,909
Business and Wholesale Revenue, Business Broadband [Member]
Revenue Accounted for Under ASC 606		15,353	15,208
Revenue Accounted for Under Other Guidance
Total Revenue		15,353	15,208
Business and Wholesale Revenue, Business Voice and Other [Member]
Revenue Accounted for Under ASC 606		6,857	7,001
Revenue Accounted for Under Other Guidance
Total Revenue		6,857	7,001
Business and Wholesale Revenue, Managed IT Services [Member]
Revenue Accounted for Under ASC 606		1,227	1,659
Revenue Accounted for Under Other Guidance
Total Revenue		1,227	1,659
Business and Wholesale Revenue, Equipment Sales and Installations [Member]
Revenue Accounted for Under ASC 606		1,414	880
Revenue Accounted for Under Other Guidance
Total Revenue		1,414	880
Business and Wholesale Revenue, Wholesale Broadband [Member]
Revenue Accounted for Under ASC 606		10,253	8,551
Revenue Accounted for Under Other Guidance
Total Revenue		10,253	8,551
Business and Wholesale Revenue, Wholesale Voice and Other [Member]
Revenue Accounted for Under ASC 606		1,288	1,426
Revenue Accounted for Under Other Guidance
Total Revenue		1,288	1,426
Business and Wholesale Revenue, Operating Leases and Other Deferred Revenue [Member]
Revenue Accounted for Under ASC 606
Revenue Accounted for Under Other Guidance		2,391	1,770
Total Revenue		2,391	1,770
Business and Wholesale Revenue [Member]
Revenue Accounted for Under ASC 606		36,392	34,725
Revenue Accounted for Under Other Guidance		2,391	1,770
Total Revenue		38,783	36,495
Consumer Revenue, Broadband [Member]
Revenue Accounted for Under ASC 606		6,692	6,468
Revenue Accounted for Under Other Guidance
Total Revenue		6,692	6,468
Consumer Revenue, Voice and Other [Member]
Revenue Accounted for Under ASC 606		2,449	2,733
Revenue Accounted for Under Other Guidance
Total Revenue		2,449	2,733
Consumer Revenue [Member]
Revenue Accounted for Under ASC 606		9,141	9,201
Revenue Accounted for Under Other Guidance
Total Revenue		9,141	9,201
Regulatory Revenue, Access, Including Customer Ordered Service and Special Access [Member]
Revenue Accounted for Under ASC 606	[1]	4,691	5,116
Revenue Accounted for Under Other Guidance	[1]
Total Revenue	[1]	4,691	5,116
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]	727	1,173
Total Revenue	[2]	727	1,173
Regulatory, High-cost Support [Member]
Revenue Accounted for Under ASC 606
Revenue Accounted for Under Other Guidance		4,924	4,924
Total Revenue		4,924	4,924
Regulatory Revenue [Member]
Revenue Accounted for Under ASC 606		4,691	5,116
Revenue Accounted for Under Other Guidance		5,651	6,097
Total Revenue		$ 10,342	$ 11,213

[1] Includes customer ordered service and special access.

[2] Includes Essential Network Support ("ENS").