CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
NET INCOME	$ 331,226	$ 386,343	$ 317,301
OTHER COMPREHENSIVE INCOME:
Total adjustments	(1,804)	(21,739)	(1,572)
Total comprehensive income	329,422	364,604	315,729
Less: Comprehensive income attributable to noncontrolling interest	(134,090)	(159,883)	(142,058)
COMPREHENSIVE INCOME ATTRIBUTABLE TO AHGP	195,332	204,721	173,671
Defined benefit pension plan
OTHER COMPREHENSIVE INCOME:
Net actuarial gain (loss)	(6,524)	(17,483)	5,110
Amortization of actuarial (gain) loss	1,788	537	366
Total adjustments	(4,736)	(16,946)	5,476
Pneumoconiosis benefits
OTHER COMPREHENSIVE INCOME:
Net actuarial gain (loss)	2,156	(4,570)	(6,872)
Amortization of actuarial (gain) loss	776	(223)	(176)
Total adjustments	$ 2,932	$ (4,793)	$ (7,048)