Retirement Plans (Pension Plan Weighted-Average Assets' Allocations) (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-Average Aset Allocation	45.00%	44.00%
Debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-Average Aset Allocation	45.00%	42.00%
Short-term fixed income [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-Average Aset Allocation	6.00%	8.00%
Real estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-Average Aset Allocation	4.00%	6.00%