Fair Value of Financial Instruments - Summary of Estimated Fair Values (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financial Instruments (Assets):
Investment securities available-for-sale, Fair Value	$ 120,121	$ 144,310
Investment securities held-to-maturity	21,689	16,583
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Instruments (Assets):
Cash and cash equivalents, Fair Value	186,302	149,711
Investment securities available-for-sale, Fair Value	0	0
Investment securities held-to-maturity	0	0
Total loans, Fair Value	0	0
Financial Instruments (Liabilities):
Noninterest bearing deposit liabilities, Fair Value	0	0
Interest-bearing deposits, Fair Value	0	0
Short Term Borrowings Fair Value Disclosure	0	0
Subordinated debt, Fair Value	0	0
Significant Other Observable Inputs (Level 2)
Financial Instruments (Assets):
Cash and cash equivalents, Fair Value	0	0
Investment securities available-for-sale, Fair Value	120,121	144,310
Investment securities held-to-maturity	17,684	12,438
Total loans, Fair Value	269,140	252,712
Financial Instruments (Liabilities):
Noninterest bearing deposit liabilities, Fair Value	0	0
Interest-bearing deposits, Fair Value	0	0
Short Term Borrowings Fair Value Disclosure	150,580	243,351
Subordinated debt, Fair Value	114,402	114,537
Significant Unobservable Inputs (Level 3)
Financial Instruments (Assets):
Cash and cash equivalents, Fair Value	0	0
Investment securities available-for-sale, Fair Value	0	0
Investment securities held-to-maturity	4,001	4,096
Total loans, Fair Value	3,466,838	3,236,345
Financial Instruments (Liabilities):
Noninterest bearing deposit liabilities, Fair Value	1,125,598	964,900
Interest-bearing deposits, Fair Value	2,739,204	2,664,872
Short Term Borrowings Fair Value Disclosure	0	0
Subordinated debt, Fair Value	0	0
Carrying Amount
Financial Instruments (Assets):
Cash and cash equivalents, Fair Value	186,302	149,711
Investment securities available-for-sale, Fair Value	120,121	144,310
Investment securities held-to-maturity	21,689	16,583
Total loans, Fair Value	3,908,949	3,737,761
Financial Instruments (Liabilities):
Noninterest bearing deposit liabilities, Fair Value	1,125,598	964,900
Interest-bearing deposits, Fair Value	2,741,602	2,665,694
Short Term Borrowings Fair Value Disclosure	150,580	243,351
Subordinated debt, Fair Value	120,587	120,454
Estimate of Fair Value Measurement
Financial Instruments (Assets):
Cash and cash equivalents, Fair Value	186,302	149,711
Investment securities available-for-sale, Fair Value	120,121	144,310
Investment securities held-to-maturity	21,685	16,534
Total loans, Fair Value	3,735,978	3,489,057
Financial Instruments (Liabilities):
Noninterest bearing deposit liabilities, Fair Value	1,125,598	964,900
Interest-bearing deposits, Fair Value	2,739,204	2,664,872
Short Term Borrowings Fair Value Disclosure	150,580	243,351
Subordinated debt, Fair Value	$ 114,402	$ 114,537