Employee Benefits (Net Periodic Benefit Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Retirement Income Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 8,530	$ 8,284	$ 9,137
Interest cost	13,477	14,001	12,742
Expected return on plan assets	(19,795)	(18,699)	(17,108)
Increase Decrease In Service and Interest Component of Net Periodic Benefit Cost Next Twelve Months	2,900
Amortization of:
Net loss	9,710	8,178	10,437
Prior service cost (benefit)	(3,467)	(2,889)	3
Net periodic benefit cost	8,455	8,875	15,211
Other Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	262	303	190
Interest cost	1,018	1,041	872
Expected return on plan assets	0	0	0
Amortization of:
Net loss	937	675	661
Prior service cost (benefit)	(39)	(17)	94
Net periodic benefit cost	$ 2,178	$ 2,002	$ 1,817