Borrowed Funds (Summary of Borrowed Funds) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Short-term borrowings:
Short-term borrowings	$ 388,923	$ 281,141
Long-term debt:
Long-term debt	362,027	423,797
Total	750,950	704,938
Securities Sold Under Repurchase Agreements [Member]
Short-term borrowings:
Short-term borrowings	8,923	11,141
Federal Home Loan Bank Advances [Member]
Short-term borrowings:
Short-term borrowings	380,000	270,000
Securities Sold Under Repurchase Agreements [Member]
Long-term debt:
Long-term debt		5,000
Federal Home Loan Bank Advances [Member]
Long-term debt:
Long-term debt	$ 362,027	$ 418,797