Employee Benefit Plans Net Periodic Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost — benefits earned during the period	$ 532	$ 523	$ 1,170
Interest cost on projected benefit obligation	4,992	6,196	5,518
Expected return on assets	(7,378)	(8,518)	(7,915)
Settlement loss	3,214	0	244
Special termination benefit recognized	3,831	0	0
Amortization of net loss (gain)	1,083	1,075	1,918
Net expense (income)	6,274	(724)	935
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost — benefits earned during the period	8	9	16
Interest cost on projected benefit obligation	371	430	418
Expected return on assets	0	0	0
Settlement loss	0	0	0
Special termination benefit recognized	0	0	0
Amortization of net loss (gain)	(97)	(60)	(64)
Net expense (income)	$ 282	$ 379	$ 370