Employee Benefit Plans Employee Benefit Plans and Components of Net Periodic Postretirement Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions paid	$ 356	$ 0
Anticipated cash contributions to pension plan in remaining fiscal year	213
Pension and Other Postretirement Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	106	112
Interest cost	1,210	1,312
Expected return on assets	(2,034)	(2,035)
Amortization of prior service cost	50	50
Amortization of actuarial loss	164	406
Net periodic pension and postretirement benefit (credit) cost	$ (504)	$ (155)