Pension and Postretirement Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2017

Retirement Benefits [Abstract]

Schedule of Defined Benefit Plans Disclosures [Table Text Block]

Net Periodic Benefit Cost (in thousands)

	Three Months Ended June 30,
	Defined Benefit Retirement Plan				Postretirement Benefits Plan
	2017		2016		2017		2016
Net Periodic Benefit Cost
Service cost	$	237	$	200	$	7	$	13
Interest cost	359		347		48		54
Amortization of net loss	509		698		2		11
Net periodic benefit cost	$	1,105	$	1,245	$	57	$	78
	Six Months Ended June 30,
	Defined Benefit Retirement Plan				Postretirement Benefits Plan
	2017		2016		2017		2016
Net Periodic Benefit Cost
Service cost	$	441	$	365	$	14	$	25
Interest cost	684		659		98		109
Amortization of net loss	850		1,158		3		23
Net periodic benefit cost	$	1,975	$	2,182	$	115	$	157