Pension and Postretirement Benefits (Tables)

6 Months Ended

Jun. 30, 2016

General Discussion Of Pension And Other Postretirement Benefits [Abstract]

Schedule of Defined Benefit Plans Disclosures [Table Text Block]

	Three Months Ended June 30,								Six Months Ended June 30,
					Other								Other
					Postretirement								Postretirement
	Pension Benefits				Benefits				Pension Benefits				Benefits
		2016		2015		2016		2015		2016		2015		2016		2015
Service cost	$	683	$	761	$	4	$	6	$	1,353	$	1,534	$	8	$	11
Interest cost		1,122		1,254		39		49		2,233		2,516		78		99
Expected return on plan assets		(1,354)		(1,396)		—		—		(2,698)		(2,798)		—		—
Actuarial loss amortization		812		877		15		26		1,620		1,758		30		52
Prior service cost amortization		(26)		(25)		—		—		(51)		(51)		—		—
Net periodic benefit cost	$	1,237	$	1,471	$	58	$	81	$	2,457	$	2,959	$	116	$	162