Fair Value Measurements (Details Textual) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Estimated value [Member]
Fair Value Measurements (Textual) [Abstract]
Carrying value of long-term obligations	$ 493,951
Carrying values [Member]
Fair Value Measurements (Textual) [Abstract]
Carrying value of long-term obligations	$ 563,201

Debt and capital lease obligations fair value disclosures.

No definition available.

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