Employee Benefit Plans (Supplemental Non-qualified Unfunded Plans) (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013
Officers and Key Employees | Supplemental Non-qualified Unfunded Plans
Deferred Compensation Arrangement with Individual, Postretirement Benefits
Compensation expense	$ 200,000	$ 300,000	$ 300,000
Amount accrued	1,600,000	1,600,000		1,500,000
Other postretirement benefits
Deferred Compensation Arrangement with Individual, Postretirement Benefits
Estimated future benefit payments 2015				500,000
Estimated future benefit payments 2016				500,000
Estimated future benefit payments 2017				500,000
Estimated future benefit payments 2018				$ 500,000