Borrowed Funds - Long-term Debt Maturities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Weighted Average Interest Rate		2.57%
Long-term advances from the FHLB	$ 45,954,000	$ 65,944,000
Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Long-term advances from the FHLB	10,911,071,000	25,946,487,000
Federal Home Loan Bank Advances | Federal Home Loan Bank Advances, July 21, 2014 Maturity, One [Member]
Debt Instrument [Line Items]
Interest Rate	2.31%	2.31%
Long-term advances from the FHLB	0	10,000,000,000
Federal Home Loan Bank Advances | Federal Home Loan Bank Advances, July 21, 2014 Maturity, Two [Member]
Debt Instrument [Line Items]
Interest Rate	2.62%	2.62%
Long-term advances from the FHLB	0	5,000,000,000
Federal Home Loan Bank Advances | Long-term Advances from the FHLB, 1/11/2015 Maturity
Debt Instrument [Line Items]
Interest Rate	2.99%	2.99%
Long-term advances from the FHLB	5,000,000,000	5,000,000,000
Federal Home Loan Bank Advances | Long-term Advances from the FHLB, 4/27/2015 Maturity
Debt Instrument [Line Items]
Interest Rate	2.97%	2.97%
Long-term advances from the FHLB	5,000,000,000	5,000,000,000
Federal Home Loan Bank Advances | Long-term Advances from the FHLB, 10/29/2018 Maturity
Debt Instrument [Line Items]
Interest Rate	0.25%	0.25%
Long-term advances from the FHLB	685,104,000	702,678,000
Federal Home Loan Bank Advances | Long-term Advances from the FHLB, 12/19/2023 Maturity
Debt Instrument [Line Items]
Interest Rate	2.00%	2.00%
Long-term advances from the FHLB	$ 225,967,000	$ 243,809,000