Derivative Financial Instruments (Derivatives not Designated as Hedging Instruments, Effect in Statements of Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	$ 0	$ 0	$ 0	$ 0
Derivatives not Designated as Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	1,050	(341)	2,122	(82)
Commitments to originate fixed rate mortgage loans to be sold [Member] | Net gains on loan sales and commissions on loans originated for others [Member] | Derivatives not Designated as Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	(855)	1,248	(1,773)	1,199
Commitments to sell fixed rate mortgage loans [Member] | Net gains on loan sales and commissions on loans originated for others [Member] | Derivatives not Designated as Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	1,753	(1,586)	3,724	(1,305)
Interest rate swaps with customers [Member] | Net gains (losses) on interest rate swaps [Member] | Derivatives not Designated as Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	(407)	398	(411)	609
Mirror swaps with counterparties [Member] | Net gains (losses) on interest rate swaps [Member] | Derivatives not Designated as Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	$ 559	$ (401)	$ 582	$ (585)