LHFI and Allowance for Loan Losses, LHFI - Additional Information (Details 2)	3 Months Ended
	Mar. 31, 2016 USD ($) KeyRatio LoanPool CreditRiskGrade	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Financing Receivable, Recorded Investment, Aging [Abstract]
Number of days used as baseline in evaluating collateral documentation exceptions for loan policy	90 days
Number of key quality ratios | KeyRatio	6
LHFS past due 90 days or more	$ 24,100,000		$ 21,800,000
Percentage of outstanding principal to be repurchased under GNMA optional repurchase program	100.00%
Amount of delinquent loans repurchased		$ 28,500,000
Repurchase gain included in gain on sales of loans		$ 304,000
Financing Receivable [Abstract]
Number of primary commercial loan groups | LoanPool	9
Number of individual credit risk grades | CreditRiskGrade	10
Minimum [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loan amount used as baseline in credit quality review for loan policy	$ 1,000,000
Financing Receivable [Abstract]
Period to conduct asset review	6 months
Credit amount used as baseline in evaluating loan policy	$ 100,000
Maximum [Member]
Financing Receivable [Abstract]
Period to conduct asset review	18 months