Retirement Plans and Other Postretirement Benefits - Reconciliation of Assets Measured at Fair Value on a Recurring Basis Utilizing Level 3 Inputs (Details 10) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Defined Benefit Plan Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 3,589	$ 2,898
Total Unrealized Gains or (Losses)
Total Realized Gains or (Losses)	0	0
Purchases	1,509	1,305
Maturities/ Redemptions	(595)	(614)
Ending Balance	4,503	3,589
Certificates of Deposit [Member]
Fair Value, Defined Benefit Plan Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	3,589	2,898
Total Unrealized Gains or (Losses)
Total Realized Gains or (Losses)
Purchases	1,509	1,305
Maturities/ Redemptions	(595)	(614)
Ending Balance	$ 4,503	$ 3,589