Employee Benefit Plans Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 579	$ 367	$ 202
Interest cost	3,405	3,413	3,087
Expected return on assets	(3,009)	(3,240)	(3,194)
Net amortization and deferral	3,127	974	2,382
Net periodic benefit cost	4,102	1,514	2,477
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	15	228
Interest cost	206	206	322
Expected return on assets	0	0	(1)
Net amortization and deferral	(258)	(347)	(363)
Net periodic benefit cost	$ (52)	$ (126)	$ 186