(3) Equity Investment in Savoy (Details) - Condensed Statement of Operations - Savoy (Equity Investmentin SELLP [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Equity Investmentin SELLP [Member]
(3) Equity Investment in Savoy (Details) - Condensed Statement of Operations - Savoy [Line Items]
Revenue	$ 12,438	$ 9,022
Expenses	(7,161)	(6,618)
Net income	$ 5,277	$ 2,404

Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains.

No definition available.

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