Employee Benefit Plans (Schedule of Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Cost) (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Supplemental Executive Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligation	3.75%	4.75%	5.50%
Discount rate for net period benefit cost	4.75%	5.50%	5.75%
Rate of compensation increase	4.50%	4.50%	4.50%
Health care cost trend rate assumed for future years
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligation	4.05%	4.75%	5.45%
Discount rate for net period benefit cost	4.75%	5.45%	5.70%
Rate of compensation increase
Health care cost trend rate assumed for future years	7.00%	7.00%	7.00%