Consolidated Statement of Operations (Parentheticals) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
(1) Included in interest expense: credits for the change in the estimated fair value of interest rate swaps.	$ 506	$ 496

(1) Included in interest expense for 2011 and 2010 were credits of $354 and $330, respectively, for the change in the estimated fair value of our interest rate swaps. Such credit amounts for the second quarter 2011 and 2010 were $166 and $191, respectively.

No definition available.

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Namespace Prefix:	hnrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration