Derivatives and Hedging Activities Offsetting Disclosure for Derivative Contracts (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Offsetting Disclosure for Derivative Contracts [Line Items]
offsetting disclosure, derivative asset, fair value, gross	$ 858	$ 4,795	$ 3,063
offsetting disclosure, offset amount, derivative liability, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative asset, falir value	858	4,795	3,063
offseting disclosure, netting adjustment, derivative liability, fair value	(858)	(4,795)	(3,032)
offsetting disclosure, collateral value, derivative asset	0	0	(31)
offsetting disclosure, net amount total, derivative asset, fair value	0	0	0
offsetting disclosure, derivative liability, fair value, gross	56,138	53,407	59,135
offsetting disclosure, offset amount, derivative asset, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative liability, falir value	56,138	53,407	59,135
offseting disclosure, netting adjustment, derivative asset, fair value	(858)	(4,795)	(3,032)
offsetting disclosure, collateral value, derivative liability	(55,280)	(48,612)	(56,103)
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	8,989	11,574	14,319
offsetting disclosure, offset amount, derivative asset, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative liability, falir value	8,989	11,574	14,319
offseting disclosure, netting adjustment, derivative asset, fair value	0	0	0
offsetting disclosure, collateral value, derivative liability	(8,989)	(11,574)	(14,319)
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	839	4,791	3,010
offsetting disclosure, offset amount, derivative liability, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative asset, falir value	839	4,791	3,010
offseting disclosure, netting adjustment, derivative liability, fair value	(839)	(4,791)	(3,010)
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	47,114	41,787	44,794
offsetting disclosure, offset amount, derivative asset, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative liability, falir value	47,114	41,787	44,794
offseting disclosure, netting adjustment, derivative asset, fair value	(839)	(4,791)	(3,010)
offsetting disclosure, collateral value, derivative liability	(46,275)	(36,996)	(41,784)
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	19	4	53
offsetting disclosure, offset amount, derivative liability, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative asset, falir value	19	4	53
offseting disclosure, netting adjustment, derivative liability, fair value	(19)	(4)	(22)
offsetting disclosure, collateral value, derivative asset	0	0	(31)
offsetting disclosure, net amount total, derivative asset, fair value	0	0	0
offsetting disclosure, derivative liability, fair value, gross	35	46	22
offsetting disclosure, offset amount, derivative asset, fair value, gross	0	0	0
offsetting disclosure, net amount, derivative liability, falir value	35	46	22
offseting disclosure, netting adjustment, derivative asset, fair value	(19)	(4)	(22)
offsetting disclosure, collateral value, derivative liability	(16)	(42)	0
offsetting disclosure, net amount total, derivative liability, fair value	$ 0	$ 0	$ 0