Derivative Financial Instruments Schedule of reduction to interest expense on borrowings related to fair value hedges (Details) (Fair Value Hedging [Member], Designated as Hedging Instrument [Member], Interest Expense [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative [Line Items]
Net reduction to interest expense on borrowings	$ 0	$ (799)	$ (1,066)	$ (2,605)
Interest Rate Swap [Member] | Interest rate swaps on senior fixed-rate notes [Member]
Derivative [Line Items]
Net reduction to interest expense on borrowings	0	(799)	(1,066)	(2,398)
Interest Rate Swap [Member] | Subordinated Debt [Member]
Derivative [Line Items]
Net reduction to interest expense on borrowings	$ 0	$ 0	$ 0	$ (207)