Loans (Narrative) (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($) loan	Sep. 30, 2015 USD ($) item loan	Sep. 30, 2014 USD ($) loan	Dec. 31, 2014 USD ($)
Accounts Notes And Loans Receivable [Line Items]
Loans	$ 283,434,000		$ 283,434,000		$ 257,085,000
Cash payments of interest	83,000	$ 52,000	251,000	$ 157,000
Loans 90 days or more past due and still accruing interest	0		0		0
Allocated specific reserves to modified TDRs	20,000		$ 20,000		64,000
Number of days of default payment			90 days
Total TDR's	5,348,000,000		$ 5,348,000,000		5,655,000,000
Accruing TDR's	4,978,000		$ 4,978,000		$ 5,233,000
Number of loans modified as a TDR | loan		0		0
Number of TDRs in payment default | loan			0	0
Recorded investment of loans undergoing modifications, not TDRs	6,915,000,000	$ 2,709,000,000	$ 6,915,000,000	$ 2,709,000,000
Minimum [Member]
Accounts Notes And Loans Receivable [Line Items]
Percent of participation agreement interest					80.00%
Maximum [Member]
Accounts Notes And Loans Receivable [Line Items]
Percent of participation agreement interest					95.00%
Mortgage Purchase Program Member [Member]
Accounts Notes And Loans Receivable [Line Items]
Percent of loans risk rated for capital adequacy			100.00%
Northpointe [Member]
Accounts Notes And Loans Receivable [Line Items]
Ownership interest in each loan is participates			5.00%		20.00%
Home Equity Line of Credit [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans	9,000		$ 9,000
Number of loans modified as a TDR | item			1
Single-Family Residential[Member]
Accounts Notes And Loans Receivable [Line Items]
Loans	9,000		$ 9,000
Number of loans modified as a TDR | loan			1
Single-Family Residential[Member] | Mortgage Purchase Program Member [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans	$ 38,850,000		$ 38,850,000		$ 24,996,000