Short and Long-Term Funding Remaining Contractual Maturity of the Securities Sold Under Agreements to Repurchase (Details) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Remaining contractual maturity of the agreements	$ 433,044,000
Gross amounts of recognized liabilities for repurchase agreements	433,044,000	$ 384,221,000
Government National Mortgage Association (GNMA) [Member]
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Remaining contractual maturity of the agreements	433,044,000
Maturity Overnight and Continuous [Member]
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Remaining contractual maturity of the agreements	433,044,000
Maturity Overnight and Continuous [Member] | Government National Mortgage Association (GNMA) [Member]
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Remaining contractual maturity of the agreements	433,044,000
Maturity Less than 30 Days [Member]
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Remaining contractual maturity of the agreements	0
Maturity Less than 30 Days [Member] | Government National Mortgage Association (GNMA) [Member]
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Remaining contractual maturity of the agreements	0
Maturity 30 to 90 Days [Member]
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Remaining contractual maturity of the agreements	0
Maturity 30 to 90 Days [Member] | Government National Mortgage Association (GNMA) [Member]
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Remaining contractual maturity of the agreements	0
Maturity Greater than 90 Days [Member]
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Remaining contractual maturity of the agreements	0
Maturity Greater than 90 Days [Member] | Government National Mortgage Association (GNMA) [Member]
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Remaining contractual maturity of the agreements	$ 0