Derivatives and Hedging Activities Offsetting Disclosure for Derivative Contracts (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Offsetting Disclosure for Derivative Contracts [Line Items]
offsetting disclosure, derivative asset, fair value, gross	$ 1,678	$ 4,795	$ 2,651
offsetting disclosure, offset amount, derivative asset, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative asset, falir value	1,678	4,795	2,651
offseting disclosure, netting adjustment, derivative asset, fair value	(1,498)	(4,795)	(2,677)
offsetting disclosure, collateral value, derivative asset	(180)	0	26
offsetting disclosure, net amount total, derivative asset, fair value	0	0	0
offsetting disclosure, derivative liability, fair value, gross	47,023	53,407	61,839
offsetting disclosure, offset amount, derivative liability, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative liability, falir value	47,023	53,407	61,839
offseting disclosure, netting adjustment, derivative liability, fair value	(1,498)	(4,795)	(2,677)
offsetting disclosure, collateral value, derivative liability	(45,525)	(48,612)	(59,162)
offsetting disclosure, net amount total, derivative liability, fair value	0	0	0
Designated as Hedging Instrument | Interest Rate Swap
Offsetting Disclosure for Derivative Contracts [Line Items]
offsetting disclosure, derivative liability, fair value, gross	7,584	11,574	13,289
offsetting disclosure, offset amount, derivative liability, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative liability, falir value	7,584	11,574	13,289
offseting disclosure, netting adjustment, derivative liability, fair value	0	0	0
offsetting disclosure, collateral value, derivative liability	(7,584)	(11,574)	(13,289)
offsetting disclosure, net amount total, derivative liability, fair value	0	0	0
Not Designated as Hedging Instrument | Interest Rate Swap
Offsetting Disclosure for Derivative Contracts [Line Items]
offsetting disclosure, derivative asset, fair value, gross	1,498	4,791	2,585
offsetting disclosure, offset amount, derivative asset, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative asset, falir value	1,498	4,791	2,585
offseting disclosure, netting adjustment, derivative asset, fair value	(1,498)	(4,791)	(2,585)
offsetting disclosure, collateral value, derivative asset	0	0	0
offsetting disclosure, net amount total, derivative asset, fair value	0	0	0
offsetting disclosure, derivative liability, fair value, gross	39,439	41,787	48,458
offsetting disclosure, offset amount, derivative liability, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative liability, falir value	39,439	41,787	48,458
offseting disclosure, netting adjustment, derivative liability, fair value	(1,498)	(4,791)	(2,585)
offsetting disclosure, collateral value, derivative liability	(37,941)	(36,996)	(45,873)
offsetting disclosure, net amount total, derivative liability, fair value	0	0	0
Not Designated as Hedging Instrument | Foreign Exchange Contract
Offsetting Disclosure for Derivative Contracts [Line Items]
offsetting disclosure, derivative asset, fair value, gross	180	4	66
offsetting disclosure, offset amount, derivative asset, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative asset, falir value	180	4	66
offseting disclosure, netting adjustment, derivative asset, fair value	0	(4)	(92)
offsetting disclosure, collateral value, derivative asset	(180)	0	26
offsetting disclosure, net amount total, derivative asset, fair value	0	0	0
offsetting disclosure, derivative liability, fair value, gross	0	46	92
offsetting disclosure, offset amount, derivative liability, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative liability, falir value	0	46	92
offseting disclosure, netting adjustment, derivative liability, fair value	0	(4)	(92)
offsetting disclosure, collateral value, derivative liability	0	(42)	0
offsetting disclosure, net amount total, derivative liability, fair value	$ 0	$ 0	$ 0