Note 6 - Current Liabilities - Summary of Advance Billings and Customer Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Advance billings	$ 3,730	$ 3,992
Customer deposits	31	32
Total advance billings and customer deposits	$ 3,761	$ 4,024

The current portion of money or property received from customers which is either to be returned upon satisfactory contract completion or applied to customer receivables in accordance with the terms of the contract or the understandings.

No definition available.

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