Fair Value Measurements (Carrying Amounts and Estimated Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financial Assets, Carrying Amount
Cash and short-term investments	$ 122,313	$ 91,059
Securities available-for-sale	407,446	194,090
Securities held-to-maturity	15,721	9,200
Restricted stock	16,572	10,092
Loans, net of allowance	1,995,103	1,069,366
Derivatives	420	993
Total financial assets	2,557,575	1,374,800
Financial Assets, Estimated Fair Value
Cash and short-term investments	122,313	91,059
Securities available-for-sale	407,446	194,090
Securities held-to-maturity	16,379	9,293
Restricted stock	16,572	10,092
Loans, net of allowance	2,016,530	1,080,820
Derivatives	420	993
Total financial assets	2,579,660	1,386,347
Financial Liabilities, Carrying Amount
Deposits	2,234,148	1,054,327
Short-term borrowings	145,993	186,009
Long-term borrowings	43,883	60,000
Derivatives	195	325
Total financial liabilities	2,424,219	1,300,661
Financial Liabilities, Estimated Fair Value
Deposits	2,161,134	1,040,402
Short-term borrowings	145,396	185,910
Long-term borrowings	43,703	59,954
Derivatives	195	325
Total financial liabilities	$ 2,350,428	$ 1,286,591