Investment Securities (Narrative) (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Schedule of Investments [Line Items]
Investment Securities average remaining life		3 years 11 months 15 days
Other than Temporary Impairment Losses, Investments	$ 0	$ 0	$ 0
Available-for-sale Securities, Gross Realized Gains	0.000	$ 0.000	$ 0.000
Asset backed securities mortgage portfolio, term		15 years
Federal Home Loan Bank Advances	1,033,000,000	$ 1,033,000,000		$ 1,072,000,000
U.S. Treasury And Sponsored Entities Callable Notes [Member]
Schedule of Investments [Line Items]
Available for Sale expected to be called	0	0
Available-for-sale securities	$ 269,100,000	$ 269,100,000
U.S. Treasury And Sponsored Entities Callable Notes [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Available for Sale Securities, Debt Maturities, Term		1 year
U.S. Treasury And Sponsored Entities Callable Notes [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Available for Sale Securities, Debt Maturities, Term		4 years