Fair Value Fair Value (Impaired Financing Receivables Additional Information) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Schedule of Impaired Financing Receivables Additional Information [Line Items]
Book Value Of Impaired Loans Carried At Fair Value	$ 4,805	$ 6,379
Partial Charge-Offs On Impaired Loans carried at Fair Value	2,593	3,681
Impaired Financing Receivable, Related Allowance	1,091	548
impaired Financing Receivable, loans not held at Fair Value, Carrying Amount	64,717	63,895
Impaired Financing Receivable, Recorded Investment	70,127	70,426	$ 78,171
Impaired Loan Fair Value	4,319	5,983
Impaired Financing Receivable, loans not held at Fair Value, Recorded Investment	65,322	64,047
Partial Charge-offs on Impaired Loans carried at Cost	21,138	21,262
Impaired Financing Receivable, Carrying Value	69,036	69,878
Partial Charge-Offs On Impaired Loans	23,731	24,943
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	1,091	548
Financing Receivable, not collateral dependent [Domain]
Schedule of Impaired Financing Receivables Additional Information [Line Items]
Impaired Financing Receivable, Related Allowance	605	152
Commercial Receivables, excluding Commercial, Financial, and Agricultural [Domain]
Schedule of Impaired Financing Receivables Additional Information [Line Items]
Impaired Financing Receivable, Related Allowance	$ 486	$ 396