Fair Value of Financial Instruments (Fair Values of Financial Assets and Liabilities on Balance Sheets) (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Financial assets:
Cash and cash equivalents	$ 67,835,000	$ 71,115,000
Investment securities	845,731,000	868,955,000
Loans (1)	2,127,828,000	2,018,482,000
Financial liabilities:
Deposits	2,579,379,000	2,540,131,000
Short-term borrowings	162,807,000	160,386,000
Long-term borrowings	151,912,000	117,299,000
Cash flow hedges (2)	219,000	0
Carrying Amount
Financial assets:
Cash and cash equivalents	67,835,000	71,115,000
Investment securities	844,248,000	868,830,000
Loans (1)	2,155,704,000	2,057,614,000
Financial liabilities:
Deposits	2,575,457,000	2,535,944,000
Short-term borrowings	162,807,000	160,386,000
Long-term borrowings	147,563,000	113,670,000
Cash flow hedges (2)	$ 219	$ 0