Other Accrued Expenses Other Accrued Expenses (Tables)

9 Months Ended

Sep. 30, 2017

Other Accrued Expenses [Abstract]

Schedule of Other Operating Cost and Expense, by Component [Table Text Block]

The following table presents the components of other accrued expenses as of:

	September 30, 2017		December 31, 2016
	(in thousands)
Employee benefits	$	14,401	$	22,282
Asset retirement obligations	13,128		9,775
Other	5,922		6,568
Other accrued expenses	$	33,451	$	38,625