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, 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
Revenues	$ 58,689	$ 58,229	$ 59,578	$ 55,972	$ 54,935	$ 56,703	$ 58,536	$ 56,731	$ 232,468	$ 226,905
Gross profit (before charge for depreciation and amortization)	30,775	31,009	33,036	30,139	28,617	30,013	32,082	31,589	124,959	122,301
Operating income	4,885	5,763	8,288	5,343	5,166	3,672	5,756	4,728	24,279	19,322
Net income	1,712	1,805	3,402	2,069	(2,976)	284	(2,830)	(708)	8,988	(6,230)
Net income attributable Alaska Communications	$ 1,720	$ 1,817	$ 3,442	$ 2,101	$ (2,947)	$ 320	$ (2,798)	$ (676)	$ 9,080	$ (6,101)
Basic (in dollars per share)	$ 0.03	$ 0.03	$ 0.06	$ 0.04	$ (0.06)	$ 0.01	$ (0.05)	$ (0.01)	$ 0.17	$ (0.12)
Diluted (in dollars per share)	$ 0.03	$ 0.03	$ 0.06	$ 0.04	$ (0.06)	$ 0.01	$ (0.05)	$ (0.01)	$ 0.17	$ (0.12)