Employee Benefit Plans Amounts Recognized in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax
Unrecognized prior service cost	$ 80	$ 90
Unrecognized net loss/(gain)	18,570	21,420
Total accumulated other comprehensive income (loss) recognized at December 31	18,650	21,510
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax
Unrecognized prior service cost	0	0
Unrecognized net loss/(gain)	(840)	(670)
Total accumulated other comprehensive income (loss) recognized at December 31	$ (840)	$ (670)