Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2016

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Finite-Lived Intangible Assets

Intangible assets other than goodwill, which are subject to amortization, consist of the following:

	Gross Carrying Amount		Accumulated Amortization			Net Balance
Balance at December 31, 2016
NACoal:
Coal supply agreement	$	84,200	$	(38,523	)	$	45,677
HBB:
Customer relationships	$	5,760	$	(1,960	)	$	3,800
Trademarks	3,100		(408		)	2,692
Other intangibles	1,240		(450		)	790
	$	10,100	$	(2,818	)	$	7,282
Balance at December 31, 2015
NACoal:
Coal supply agreement	$	84,200	$	(36,020	)	$	48,180
HBB:
Customer relationships	$	5,760	$	(1,000	)	$	4,760
Trademarks	3,100		(208		)	2,892
Other intangibles	1,240		(229		)	1,011
	$	10,100	$	(1,437	)	$	8,663