Summary of Significant Accounting Policies Allowance For Credit Losses (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due For Nonaccrual Status	90 days
Impaired Loan Balances Allocated Reserves	$ 1.0
Percentage Threshold Of Companies Current Loan To Value Ratio Of Original Appraisals Used	70.00%
Impaired Loans with Principal Balances Approximately In Percentage	68.00%	78.00%
Impaired Loans Balances, Real Estate as Collateral	$ 1.0