Disposal group including discontinued operation ownership percentage sold.

No definition available.

Name:	alsk_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageSold
Namespace Prefix:	alsk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Significant Accounting Policies [Line Items]

+ References

No definition available.

+ Details

Name:	alsk_SignificantAccountingPoliciesLineItems
Namespace Prefix:	alsk_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=64801991&loc=SL6759159-111685

+ Details

Name:	us-gaap_VariableInterestEntityOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_NoncontrollingInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=alsk_QuintillionHoldingCompanyLimitedLiabilityCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=alsk_AlaskaWirelessNetworkMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=alsk_AcsCableSystemsLlcAndQuintillionHoldingsLlcJointVentureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Summary of Significant Accounting Policies - Additional Information (Detail)			9 Months Ended
	Apr. 02, 2015	Feb. 02, 2015	Sep. 30, 2016	Feb. 01, 2015
Significant Accounting Policies [Line Items]
Percentage of ownership interest sold in wireless operation		33.33%
Percentage ownership interest in joint venture			50.00%
Noncontrolling Interests [Member] \| Quintillion Holdings, LLC [Member]
Significant Accounting Policies [Line Items]
Percentage ownership interest in joint venture			50.00%
Alaska Wireless Network, LLC [Member]
Significant Accounting Policies [Line Items]
Percentage ownership interest in equity method investment		33.33%		33.33%
ACS Cable Systems LLC and Quintillion Holdings, LLC Joint Venture [Member]
Significant Accounting Policies [Line Items]
Percentage ownership interest in joint venture	50.00%		50.00%