SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Pension Benefits and Income Taxes (Details)	12 Months Ended
Dec. 31, 2017
Income Taxes
Percentage of qualifying income for tax purposes	90.00%
Pension Plan
Employee Benefit Plans
Threshold for amortization of unrecognized actuarial gains and losses (as a percent)	10.00%

Unrecognized actuarial gains and losses as a percentage of the greater of the benefit obligation or the market-related value of plan assets, above which such gains and losses are amortized over the participants' average remaining future years of service.

No definition available.

Name:	ahgp_ThresholdPercentageForAmortizationOfUnrecognizedActuarialGainsAndLosses
Namespace Prefix:	ahgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration