Note 6 - Equity Method Investments - Summarized Financial Information (Details) - Alaska Wireless Network, LLC [Member] - USD ($) $ in Thousands	1 Months Ended		3 Months Ended	12 Months Ended
	Feb. 02, 2015		Mar. 31, 2015	Dec. 31, 2017		Dec. 31, 2016
Operating revenues	$ 21,457
Gross profit	15,745
Operating income	9,757
Net income	9,722
Adjusted free cash flow (1)	$ 10,805	[1]	$ 764		[1]		[1]

[1] Adjusted free cash flow is defined in the Operating Agreement.