Retirement Plans Components of Net Periodic Benefit Cost for the Pension and Postretirement Tables (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Plans, Defined Benefit [Member]
Net period benefit cost for the pension and postretirement plans
Service cost	$ 12,078	$ 10,287	$ 9,898
Interest cost	6,237	6,547	6,414
Expected return on plan assets	(17,647)	(14,713)	(12,896)
Amortization of prior service cost	72	72	72
Amortization of actuarial (gain) loss	4,344	2,708	2,024
Settlement charge	0	408	0
Total net pension cost	5,084	5,309	5,512
Other Postretirement Benefit Plans, Defined Benefit [Member]
Net period benefit cost for the pension and postretirement plans
Service cost	0	0
Interest cost	142	182	198
Amortization of prior service cost	0	170	395
Amortization of actuarial (gain) loss		0	0
Settlement charge	0	0	0
Total net pension cost	$ 142	$ 352	$ 593