Revenue Recognition (Tables)

6 Months Ended

Jun. 30, 2018

Revenue from Contract with Customer [Abstract]

Schedule of effects of revenue recognition

	PRB		MET		Other Thermal		Corporate, Other and Eliminations			Consolidated
	(in thousands)
Three Months Ended June 30, 2018
North America revenues	$	229,035	$	38,323	$	40,547	$	3,625		$	311,530
Seaborne revenues	843		220,709		59,267		—			280,819
Total revenues	$	229,878	$	259,032	$	99,814	$	3,625		$	592,349
Three Months Ended June 30, 2017
North America revenues	$	230,579	$	82,498	$	71,539	$	(1	)	$	384,615
Seaborne revenues	—		145,151		20,100		—			165,251
Total revenues	$	230,579	$	227,649	$	91,639	$	(1	)	$	549,866

	PRB		MET		Other Thermal		Corporate, Other and Eliminations		Consolidated
	(in thousands)
Six Months Ended June 30, 2018
North America revenues	$	473,395	$	68,001	$	84,214	$	3,625	$	629,235
Seaborne revenues	1,911		429,378		107,120		—		538,409
Total revenues	$	475,306	$	497,379	$	191,334	$	3,625	$	1,167,644
Six Months Ended June 30, 2017
North America revenues	$	504,007	$	151,233	$	140,503	$	57	$	795,800
Seaborne revenues	—		301,999		53,042		—		355,041
Total revenues	$	504,007	$	453,232	$	193,545	$	57	$	1,150,841