Securities (Carrying Value of Securities Pledged as Collateral) (Details) $ in Thousands	Sep. 30, 2019 USD ($)
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Restricted	$ 710,468
To secure public funds
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Restricted	443,320
To secure borrowings
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Restricted	111,421
Other securities pledged
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Restricted	$ 155,727