Note 11 - Revenue Streams and Concentrations - Revenue Streams (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues		$ 16,200	$ 16,252	$ 16,890	$ 16,726	$ 16,794	$ 16,946	$ 17,406	$ 17,380	$ 66,068	$ 68,526	$ 68,944
Revenues, percentage										100.00%
Month-to-Month Customers [Member]
Revenues, within scope of ASU 2014-09										$ 30,117
Revenues, percentage within scope of ASU 2014-09										61.70%
Month-to-Month Customers [Member] | Sales Revenue, Services, Net [Member]
Revenues, percentage										45.60%
Competitive Local Exchange Carrier Business Customers [Member]
Revenues, within scope of ASU 2014-09										$ 14,061
Revenues, percentage within scope of ASU 2014-09										28.70%
Competitive Local Exchange Carrier Business Customers [Member] | Sales Revenue, Services, Net [Member]
Revenues, percentage										21.30%
Network Access Customers [member]
Revenues, within scope of ASU 2014-09										$ 2,713
Revenues, percentage within scope of ASU 2014-09										5.60%
Network Access Customers [member] | Sales Revenue, Services, Net [Member]
Revenues, percentage										4.10%
Month-to-Month, Competitive Local Exchange Carrier Business, and Network Access Customers [Member]
Revenues, within scope of ASU 2014-09										$ 46,891
Revenues, percentage within scope of ASU 2014-09										96.00%
Month-to-Month, Competitive Local Exchange Carrier Business, and Network Access Customers [Member] | Sales Revenue, Services, Net [Member]
Revenues, percentage										71.00%
Global Access Customers [Member]
Revenues, within scope of ASU 2014-09	[1]									$ 1,932
Revenues, percentage within scope of ASU 2014-09	[1]									4.00%
Global Access Customers [Member] | Sales Revenue, Services, Net [Member]
Revenues, percentage	[1]									2.90%
Month-to-Month, Competitive Local Exchange Carrier Business, Network Access, and Global Access Customers [Member]
Revenues, within scope of ASU 2014-09										$ 48,823
Revenues, percentage within scope of ASU 2014-09										100.00%
Month-to-Month, Competitive Local Exchange Carrier Business, Network Access, and Global Access Customers [Member] | Sales Revenue, Services, Net [Member]
Revenues, percentage										73.90%
Managed Services [Member]
Revenues	[2]									$ 639
Managed Services [Member] | Sales Revenue, Services, Net [Member]
Revenues, percentage	[2]									1.00%
Sales Channel, Directly to Consumer [Member]
Revenues										$ 49,462
Sales Channel, Directly to Consumer [Member] | Sales Revenue, Services, Net [Member]
Revenues, percentage										74.90%
Local services [Member]
Revenues										$ 21,507
Local services [Member] | Sales Channel, Directly to Consumer [Member]
Revenues										21,507
Network Access [Member]
Revenues										21,100
Network Access [Member] | Sales Channel, Directly to Consumer [Member]
Revenues										4,645
Internet [Member]
Revenues										15,224
Internet [Member] | Sales Channel, Directly to Consumer [Member]
Revenues										15,224
Transport Services [Member]
Revenues										4,774
Transport Services [Member] | Sales Channel, Directly to Consumer [Member]
Revenues										4,623
Video and Security [Member]
Revenues										2,824
Video and Security [Member] | Sales Channel, Directly to Consumer [Member]
Revenues										2,824
Management Service [Member]
Revenues										639
Management Service [Member] | Sales Channel, Directly to Consumer [Member]
Revenues										639
Indefeasible Rights-Of-Use Agreements, Outside of ASU 2014-09 Scope [Member]
Revenues	[2]									$ 151
Indefeasible Rights-Of-Use Agreements, Outside of ASU 2014-09 Scope [Member] | Sales Revenue, Services, Net [Member]
Revenues, percentage	[2]									0.20%
Network Access, Outside of ASU 2014-09 Scope [Member]
Revenues	[2]									$ 16,455
Network Access, Outside of ASU 2014-09 Scope [Member] | Sales Revenue, Services, Net [Member]
Revenues, percentage	[2]									24.90%

[1] Fixed fees charged to MTM customers and CLEC business customers.

[2] Revenue generated from sources not within the scope of ASU 2014-09.