Accrued Liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Accrued Liabilities [Abstract]

Accrued Liabilities [Table Text Block]

Accrued liabilities consisted of the following as of December 31:

	2017		2016
	(In thousands)
Employee costs	$	19,521	$	15,394
Lease operating expenses	11,819		10,075
Interest payable	6,745		6,524
Taxes	3,404		2,219
Third-party credits	2,240		2,998
Other	4,794		2,441
Total accrued liabilities	$	48,523	$	39,651