Accrued Liabilities (Tables)

12 Months Ended

Dec. 31, 2018

Accrued Liabilities [Abstract]

Accrued Liabilities [Table Text Block]

Accrued liabilities consisted of the following as of December 31:

	2018		2017
	(In thousands)
Employee costs	$	22,056	$	19,521
Lease operating expenses	12,756		11,819
Interest payable	6,635		6,745
Third-party credits	2,129		2,240
Taxes	1,378		3,404
Other	4,710		4,794
Total accrued liabilities	$	49,664	$	48,523