Note 2 - Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Revenue Accounted for Under ASC 606		$ 49,042	$ 47,758
Revenue Accounted for Under Other Guidance		7,867	8,214
Total Revenue		56,909	55,972
Business and Wholesale Revenue, Business Broadband [Member]
Revenue Accounted for Under ASC 606		15,208	13,600
Revenue Accounted for Under Other Guidance
Total Revenue		15,208	13,600
Business and Wholesale Revenue, Business Voice and Other [Member]
Revenue Accounted for Under ASC 606		7,001	6,851
Revenue Accounted for Under Other Guidance
Total Revenue		7,001	6,851
Business and Wholesale Revenue, Managed IT Services [Member]
Revenue Accounted for Under ASC 606		1,659	1,265
Revenue Accounted for Under Other Guidance
Total Revenue		1,659	1,265
Business and Wholesale Revenue, Equipment Sales and Installations [Member]
Revenue Accounted for Under ASC 606		880	922
Revenue Accounted for Under Other Guidance
Total Revenue		880	922
Business and Wholesale Revenue, Wholesale Broadband [Member]
Revenue Accounted for Under ASC 606		8,551	8,056
Revenue Accounted for Under Other Guidance
Total Revenue		8,551	8,056
Business and Wholesale Revenue, Wholesale Voice and Other [Member]
Revenue Accounted for Under ASC 606		1,426	1,488
Revenue Accounted for Under Other Guidance
Total Revenue		1,426	1,488
Business and Wholesale Revenue, Operating Leases and Other Deferred Revenue [Member]
Revenue Accounted for Under ASC 606
Revenue Accounted for Under Other Guidance		1,770	1,581
Total Revenue		1,770	1,581
Business and Wholesale Revenue [Member]
Revenue Accounted for Under ASC 606		34,725	32,182
Revenue Accounted for Under Other Guidance		1,770	1,581
Total Revenue		36,495	33,763
Consumer Revenue, Broadband [Member]
Revenue Accounted for Under ASC 606		6,468	6,492
Revenue Accounted for Under Other Guidance
Total Revenue		6,468	6,492
Consumer Revenue, Voice and Other [Member]
Revenue Accounted for Under ASC 606		2,733	2,877
Revenue Accounted for Under Other Guidance
Total Revenue		2,733	2,877
Consumer Revenue [Member]
Revenue Accounted for Under ASC 606		9,201	9,369
Revenue Accounted for Under Other Guidance
Total Revenue		9,201	9,369
Regulatory Revenue, Access, Including Customer Ordered Service and Special Access [Member]
Revenue Accounted for Under ASC 606	[1]	5,116	6,207
Revenue Accounted for Under Other Guidance	[1]
Total Revenue	[1]	5,116	6,207
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]	1,173	1,710
Total Revenue	[2]	1,173	1,710
Regulatory, High-cost Support [Member]
Revenue Accounted for Under ASC 606
Revenue Accounted for Under Other Guidance		4,924	4,923
Total Revenue		4,924	4,923
Regulatory Revenue [Member]
Revenue Accounted for Under ASC 606		5,116	6,207
Revenue Accounted for Under Other Guidance		6,097	6,633
Total Revenue		$ 11,213	$ 12,840

[1] Includes customer ordered service and special access.

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