Note 2 - Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue Accounted for Under ASC 606		$ 49,827		$ 148,967
Revenue Accounted for Under Other Guidance		8,402		24,812
Operating revenues		58,229	$ 56,703	173,779	$ 171,970
Business and Wholesale Revenue, Business Broadband [Member]
Revenue Accounted for Under ASC 606		15,309		45,859
Revenue Accounted for Under Other Guidance
Operating revenues		15,309		45,859
Business and Wholesale Revenue, Business Voice and Other [Member]
Revenue Accounted for Under ASC 606		7,199		21,088
Revenue Accounted for Under Other Guidance
Operating revenues		7,199		21,088
Business and Wholesale Revenue, Managed IT Services [Member]
Revenue Accounted for Under ASC 606		1,480		3,936
Revenue Accounted for Under Other Guidance
Operating revenues		1,480		3,936
Business and Wholesale Revenue, Equipment Sales and Installations [Member]
Revenue Accounted for Under ASC 606		1,488		3,870
Revenue Accounted for Under Other Guidance
Operating revenues		1,488		3,870
Business and Wholesale Revenue, Wholesale Broadband [Member]
Revenue Accounted for Under ASC 606		7,624		23,475
Revenue Accounted for Under Other Guidance
Operating revenues		7,624		23,475
Business and Wholesale Revenue, Wholesale Voice and Other [Member]
Revenue Accounted for Under ASC 606		1,525		4,455
Revenue Accounted for Under Other Guidance
Operating revenues		1,525		4,455
Business and Wholesale Revenue, Operating Leases and Other Deferred Revenue [Member]
Revenue Accounted for Under ASC 606
Revenue Accounted for Under Other Guidance		1,740		4,923
Operating revenues		1,740		4,923
Business and Wholesale Revenue [Member]
Revenue Accounted for Under ASC 606		34,625		102,683
Revenue Accounted for Under Other Guidance		1,740		4,923
Operating revenues		36,365		107,606
Consumer Revenue, Broadband [Member]
Revenue Accounted for Under ASC 606		6,539		19,726
Revenue Accounted for Under Other Guidance
Operating revenues		6,539		19,726
Consumer Revenue, Voice and Other [Member]
Revenue Accounted for Under ASC 606		2,719		8,355
Revenue Accounted for Under Other Guidance
Operating revenues		2,719		8,355
Consumer Revenue [Member]
Revenue Accounted for Under ASC 606		9,258		28,081
Revenue Accounted for Under Other Guidance
Operating revenues		9,258		28,081
Regulatory Revenue, Access, Including Customer Ordered Service and Special Access [Member]
Revenue Accounted for Under ASC 606	[1]	5,944		18,203
Revenue Accounted for Under Other Guidance	[1]
Operating revenues	[1]	5,944		18,203
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]	1,738		5,118
Operating revenues	[2]	1,738		5,118
Regulatory, High-cost Support [Member]
Revenue Accounted for Under ASC 606
Revenue Accounted for Under Other Guidance		4,924		14,771
Operating revenues		4,924		14,771
Regulatory Revenue [Member]
Revenue Accounted for Under ASC 606		5,944		18,203
Revenue Accounted for Under Other Guidance		6,662		19,889
Operating revenues		$ 12,606		$ 38,092

[1] Includes customer ordered service and special access.

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