Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2016

Related Party Transactions [Abstract]

Schedule of Related Party Transactions [Table Text Block]

	Year Ended
	December 31, 2016		December 31, 2015		December 31, 2014
	(In thousands)
Indirect charges:
Operating and maintenance expenses	$	65,347	$	59,863	$	57,182
Selling, general and administrative expenses	9,747		9,443		8,895
Total indirect charges	$	75,094	$	69,306	$	66,077