Retirement Plans Other Changes in Plan Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Amortization of prior service cost	$ 72	$ 242	$ 467
Amortization of actuarial gain (loss)	40,148	(6,941)	(14,810)
Income tax (expense) benefit	(15,562)	2,366	5,674
Other comprehensive income (loss) on pension and postretirement obligations	24,658	(4,333)	(8,669)
Pension Plans, Defined Benefit [Member]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Net gain (loss)	35,366	(9,735)
Amortization of prior service cost	72	72
Amortization of actuarial gain (loss)	4,344	3,073
Income tax (expense) benefit	(15,394)	2,324
Other comprehensive income (loss) on pension and postretirement obligations	24,388	(4,266)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Net gain (loss)	438	(279)
Amortization of prior service cost	0	170
Amortization of actuarial gain (loss)	0	0
Income tax (expense) benefit	(168)	42
Other comprehensive income (loss) on pension and postretirement obligations	$ 270	$ (67)