Disclosures of Fair Values of Financial Instruments, Part II (Details) - USD ($)		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Foreclosed Assets Held for Sale [Abstract]
Other real estate owned		$ 2,534,000	$ 2,754,000
Financial Assets [Abstract]
Available-for-sale securities		692,274,000	578,579,000
Debt Securities, Held-to-maturity		69,436,000	69,332,000
Debt Securities, Held-to-maturity, Fair Value		67,909,000	68,457,000
Other borrowings		7,724,000	10,313,000
Carrying Amount
Financial Assets [Abstract]
Cash and due from banks		140,735,000	88,388,000
Federal funds sold		665,000	491,000
Certificates of deposit investments		7,569,000	1,685,000
Available-for-sale securities		692,274,000	578,579,000
Debt Securities, Held-to-maturity		69,436,000
Debt Securities, Held-to-maturity, Fair Value			69,332,000
Loans held for sale		1,508,000	1,025,000
Loans net of allowance for loan losses		2,616,822,000	1,918,499,000
Interest receivable		16,881,000	10,832,000
Federal Reserve Bank stock		7,390,000	5,160,000
Federal Home Loan Bank stock		3,095,000	2,407,000
Deposits		2,988,686,000	2,274,639,000
Securities sold under agreements to repurchase		192,330,000	155,388,000
Interest payable		1,758,000	602,000
Federal Home Loan Bank borrowings		119,745,000	60,038,000
Long-term Debt, Fair Value			10,313,000
Other borrowings		7,724,000
Junior subordinated debentures		29,000,000	24,000,000
Fair Value
Financial Assets [Abstract]
Cash and due from banks		140,735,000	88,388,000
Federal funds sold		665,000	491,000
Certificates of deposit investments		7,569,000	1,692,000
Available-for-sale securities		692,274,000	578,579,000
Debt Securities, Held-to-maturity, Fair Value		67,909,000	68,457,000
Loans held for sale		1,508,000	1,025,000
Loans net of allowance for loan losses		2,541,037,000	1,899,678,000
Interest receivable		16,881,000	10,832,000
Federal Reserve Bank stock		7,390,000	5,160,000
Federal Home Loan Bank stock		3,095,000	2,407,000
Deposits		2,991,177,000	2,272,868,000
Securities sold under agreements to repurchase		192,179,000	155,394,000
Interest payable		1,758,000	602,000
Federal Home Loan Bank borrowings		119,704,000	59,968,000
Long-term Debt, Fair Value			10,313,000
Other borrowings		7,724,000
Junior subordinated debentures		24,418,000	18,050,000
Fair Value, Measurements, Nonrecurring [Member] | Carrying Amount
Foreclosed Assets Held for Sale [Abstract]
Other real estate owned		2,534,000	2,754,000
Fair Value, Measurements, Nonrecurring [Member] | Fair Value
Foreclosed Assets Held for Sale [Abstract]
Other real estate owned		836,000	91,000
Fair Value, Inputs, Level 1 [Member]
Financial Assets [Abstract]
Cash and due from banks		140,735,000	88,388,000
Federal funds sold		665,000	491,000
Certificates of deposit investments		0	0
Available-for-sale securities		364,000	172,000
Loans held for sale		0	0
Loans net of allowance for loan losses		0	0
Interest receivable		0	0
Federal Reserve Bank stock		0	0
Federal Home Loan Bank stock		0	0
Deposits		0	0
Securities sold under agreements to repurchase		0	0
Interest payable		0	0
Federal Home Loan Bank borrowings		0	0
Long-term Debt, Fair Value			0
Other borrowings		0
Junior subordinated debentures		0	0
Fair Value, Inputs, Level 2 [Member]
Financial Assets [Abstract]
Cash and due from banks		0	0
Federal funds sold		0	0
Certificates of deposit investments		7,569,000	1,692,000
Available-for-sale securities		690,943,000	575,859,000
Debt Securities, Held-to-maturity, Fair Value		67,909,000	68,457,000
Loans held for sale		1,508,000	1,025,000
Loans net of allowance for loan losses		0	0
Interest receivable		16,881,000	10,832,000
Federal Reserve Bank stock		7,390,000	5,160,000
Federal Home Loan Bank stock		3,095,000	2,407,000
Deposits		2,396,917,000	1,930,604,000
Securities sold under agreements to repurchase		192,179,000	155,394,000
Interest payable		1,758,000	602,000
Federal Home Loan Bank borrowings		119,704,000	59,968,000
Long-term Debt, Fair Value			10,313,000
Other borrowings		7,724,000
Junior subordinated debentures		24,418,000	18,050,000
Fair Value, Inputs, Level 3 [Member]
Financial Assets [Abstract]
Cash and due from banks		0	0
Federal funds sold		0	0
Certificates of deposit investments		0	0
Available-for-sale securities		967,000	2,548,000
Loans held for sale		0	0
Loans net of allowance for loan losses		2,541,037,000	1,899,678,000
Interest receivable		0	0
Federal Reserve Bank stock		0	0
Federal Home Loan Bank stock		0	0
Deposits		594,260,000	342,264,000
Securities sold under agreements to repurchase		0	0
Interest payable		0	0
Federal Home Loan Bank borrowings		0	0
Long-term Debt, Fair Value			0
Other borrowings		0
Junior subordinated debentures		0	0
Trust preferred securities | Fair Value, Measurements, Recurring [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure			$ 2,548,000
Trust preferred securities | Fair Value, Inputs, Level 3 [Member] | Discounted Cash Flow [Member]
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract]
Constant prepayment rate (in hundredths)	[1]		1.30%
Trust preferred securities | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract]
Discount rate (in hundredths)			12.70%
Cumulative projected prepayments (in hundredths)			21.60%
Probability of default (in hundredths)			0.50%
Projected cures given deferral (in hundredths)			0.00%
Loss severity			97.70%
Trust preferred securities | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract]
Discount rate (in hundredths)
Cumulative projected prepayments (in hundredths)
Probability of default (in hundredths)
Projected cures given deferral (in hundredths)
Loss severity
Trust preferred securities | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Discounted Cash Flow [Member]
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract]
Discount rate (in hundredths)
Cumulative projected prepayments (in hundredths)
Probability of default (in hundredths)
Projected cures given deferral (in hundredths)
Loss severity
Impaired loans (collateral dependent) | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		16,437,000	$ 3,053,000
Impaired loans (collateral dependent) | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		0	0
Impaired loans (collateral dependent) | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		$ 0	$ 0
Impaired loans (collateral dependent) | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Third Party Valuations [Member]
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract]
Discount to reflect realizable value (in hundredths)		0.00%	0.00%
Impaired loans (collateral dependent) | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Third Party Valuations [Member]
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract]
Discount to reflect realizable value (in hundredths)		40.00%	40.00%
Impaired loans (collateral dependent) | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Third Party Valuations [Member]
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract]
Discount to reflect realizable value (in hundredths)		20.00%	20.00%
Impaired loans (collateral dependent) | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		$ 16,437,000	$ 3,053,000
Foreclosed assets held for sale | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		836,000	91,000
Foreclosed assets held for sale | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		0	0
Foreclosed assets held for sale | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		$ 0	$ 0
Foreclosed assets held for sale | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Third Party Valuations [Member]
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract]
Discount to reflect realizable value less estimated selling costs (in hundredths)		0.00%	0.00%
Foreclosed assets held for sale | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Third Party Valuations [Member]
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract]
Discount to reflect realizable value less estimated selling costs (in hundredths)		40.00%	40.00%
Foreclosed assets held for sale | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Third Party Valuations [Member]
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract]
Discount to reflect realizable value less estimated selling costs (in hundredths)		35.00%	35.00%
Foreclosed assets held for sale | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure		$ 836,000	$ 91,000

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