Employee Benefits (Recognized in Other Comprehensive Income and Net Periodic Benefit Costs - Retirement Plans) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Retirement Income Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total recognized in net periodic benefit cost and other comprehensive income	$ 9,631	$ 6,478	$ 17,210
Other Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total recognized in net periodic benefit cost and other comprehensive income	$ 2,440	$ 469	$ 4,352