Loans and the Allowance for Loan and Lease Losses (Details)	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Loans and the Allowance for Loan and Lease Losses (Details) [Line Items]
Number of Segments of Loans and Leases		5
Non Accrual Contractual Due		90 days
Threshold to Determine Impaired Loans		$ 250,000
Period Considered to Calculate Actual Loss		3 years
Loans Pledged as Collateral	$ 1,600,000,000	$ 1,600,000,000		$ 1,000,000,000
Financing Receivable, Collectively Evaluated for Impairment	2,856,519,000	2,856,519,000		2,516,251,000
Commitments to Lend Additional Funds		0
Financing Receivable, Modifications, Recorded Investment	77,100,000	77,100,000		2,800,000
Loans Modified In Troubled Debt Restructuring On Non Accrual Status		1,100,000		1,000,000
Allocations Related to Troubled Debt Restructuring	2.0	2.0	$ 0
Allowance for Loan and Lease Losses Period Increase Decrease Due to Trouble Debt Restructuring	2.0	2.0
Valuation per Medallion Amount	814,000	$ 814,000
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum		3.00%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum		3.25%
Debt Instrument, Interest Rate, Increase (Decrease)		3.75%
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down		$ 0	$ 333,000
Financing Receivable, Modifications, Subsequent Default, Number of Contracts		0	0
Acquired Loans [Member]
Loans and the Allowance for Loan and Lease Losses (Details) [Line Items]
Financing Receivable, Collectively Evaluated for Impairment	$ 900,000,000	$ 900,000,000		$ 1,200,000,000
Minimum [Member]
Loans and the Allowance for Loan and Lease Losses (Details) [Line Items]
Amortization Period For Interest		25 years
Maximum [Member]
Loans and the Allowance for Loan and Lease Losses (Details) [Line Items]
Amortization Period For Interest		30 years