Revenue Recognition (Tables)

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Schedule of effects of revenue recognition

	PRB		MET		Other Thermal		Corporate, Other and Eliminations		Consolidated
	(in thousands)
Year Ended December 31, 2018
North America revenues	$	971,337	$	160,969	$	195,547	$	13,034	$	1,340,887
Seaborne revenues	1,911		875,652		233,337		—		1,110,900
Total revenues	$	973,248	$	1,036,621	$	428,884	$	13,034	$	2,451,787
Year Ended December 31, 2017
North America revenues	$	1,024,197	$	312,874	$	269,007	$	16,083	$	1,622,161
Seaborne revenues	—		574,965		127,497		—		702,462
Total revenues	$	1,024,197	$	887,839	$	396,504	$	16,083	$	2,324,623
October 2 through December 31, 2016
North America revenues	$	275,703	$	91,086	$	76,646	$	2,226	$	445,661
Seaborne revenues	—		109,291		20,736		—		130,027
Total revenues	$	275,703	$	200,377	$	97,382	$	2,226	$	575,688
January 1 through October 1, 2016
North America revenues	$	726,747	$	215,585	$	211,153	$	21,841	$	1,175,326
Seaborne revenues	—		221,484		1,899		—		223,383
Total revenues	$	726,747	$	437,069	$	213,052	$	21,841	$	1,398,709