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EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS - ADDITIONAL INFORMATION (Details) | 12 Months Ended
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Dec. 31, 2015 plan
Compensation and Retirement Disclosure [Abstract] |
Number of defined benefit plans | 4
Number of defined contribution plans | 5

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- Definition Number of Defined Benefit Plans + References No definition available. + Details
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- Definition Number of Defined Contribution Plans + References No definition available. + Details
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Namespace Prefix: | alk_
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Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
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