Revenue Recognition (Tables)

3 Months Ended

Mar. 31, 2019

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 March 31, 2019
North America revenues	$	212,729	$	44,666	$	46,529	$	3,214	$	307,138
Seaborne revenues	—		208,596		39,449		—		248,045
Total revenues	$	212,729	$	253,262	$	85,978	$	3,214	$	555,183
Three Months Ended March 31, 2018
North America revenues	$	244,360	$	29,678	$	43,667	$	—	$	317,705
Seaborne revenues	1,068		208,669		47,853		—		257,590
Total revenues	$	245,428	$	238,347	$	91,520	$	—	$	575,295