Interest Expense (Tables)

3 Months Ended

Mar. 31, 2017

Interest Costs Incurred [Abstract]

Interest Expense

			Three Months Ended
			March 31,
			2017		2016
Senior notes			$	7,986	$	9,562
Credit facility unutilized fee				558		768
Federal coal lease obligations imputed interest				86		82
Amortization of deferred financing costs and
	original issue discount			1,986		1,051
Other				714		59
		Subtotal		11,330		11,522
Premium on early retirement of debt				880		—
Write-off of deferred financing costs
	and original issue discount			702		—
Other				—		—
		Total cost of early retirement of debt and refinancings		1,582		—
Total interest expense				12,912		11,522
Less interest capitalized				—		(471)
Net interest expense			$	12,912	$	11,051