Note 20 - Selected Quarterly Financial Information - Summary of Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating revenues	$ 54,935	$ 56,703	$ 58,536	$ 56,731	$ 57,793	$ 56,483	$ 56,262	$ 56,328	$ 226,905	$ 226,866	$ 232,817
Gross profit (before charge for depreciation and amortization)	28,617	30,013	32,082	31,589	32,720	31,090	30,719	30,200	122,301	124,729
Operating income	5,012	3,519	5,602	4,574	6,728	4,100	4,365	4,316	18,707	19,509	47,746
Net (loss) income	(2,976)	284	(2,830)	(708)	1,597	320	283	53	(6,230)	2,253	12,885
Net (loss) income attributable Alaska Communications	$ (2,947)	$ 320	$ (2,798)	$ (676)	$ 1,629	$ 354	$ 317	$ 86	$ (6,101)	$ 2,386	$ 12,954
Diluted (in dollars per share)	$ (0.06)	$ 0.01	$ (0.05)	$ (0.01)	$ 0.03	$ 0.01	$ 0.01		$ (0.12)	$ 0.05	$ 0.26
Diluted (in dollars per share)					$ 0.03	$ 0.01	$ 0.01		$ (0.12)	$ 0.05	$ 0.25