Securities (Carrying Value of Securities Pledged as Collateral) (Details) $ in Thousands	Mar. 31, 2021 USD ($)
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Restricted	$ 804,675
To secure public funds
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Restricted	477,970
To secure borrowings
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Restricted	109,650
Other securities pledged
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Restricted	$ 217,055