Equity Method Investments (Tables)

12 Months Ended

Dec. 31, 2017

Equity Method Investments And Joint Ventures Abstract

Equity method investments table

		2017		2016
Venture Fuels Partnership	$	3,774	$	7,575
Other		989		1,006
Total equity method investments	$	4,763	$	8,581

Income (loss) from unconsolidated affiliates

	2017		2016		2015
Venture Fuels Partnership	$	700	$	2,394	$	1,801
Gateway Pacific Terminal		—		(1,753)		(613)
Other		13		16		11
Income (loss) from unconsolidated affiliates, net of tax	$	713	$	657	$	1,200

Related Party Transactions [Abstract]

Summary of related party transactions

	2017		2016		2015
Sales of coal to Venture Fuels Partnership	$	9,528	$	11,922	$	26,754