Note 2 - Joint Venture - Certain Financial Information About the Joint Venture Included On the Company's Consolidated Balance Sheet (Details) (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
ACS Cable Systems LLC and Quintillion Holdings, LLC Joint Venture [Member]
Accumulated depreciation of IRU assets, net	$ 186	$ 112

Represents the amount of accumulated depreciation related to indefeasible right of use assets.

No definition available.

Name:	alsk_AccumulatedDepreciationIndefeasibleRightOfUseAssets
Namespace Prefix:	alsk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant