Disclosures of Fair Values of Financial Instruments, Part II (Details) - USD ($)		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Foreclosed Assets Held for Sale [Abstract]
Other real estate owned		$ 1,982,000	$ 477,000
Assets Measured On Recurring And Nonrecurring Basis Valuation Techniques [Abstract]
Assets, Fair Value Disclosure, Recurring		1,652,000	1,906,000
Financial Assets [Abstract]
Available-for-sale securities		619,848,000	518,848,000
Held-to-maturity Securities		74,231,000	85,208,000
Held-to-maturity Securities, Fair Value		73,096,000	85,737,000
Carrying Amount
Financial Assets [Abstract]
Cash and due from banks		137,002,000	115,292,000
Federal funds sold		38,900,000	492,000
Certificates of deposit investments		14,643,000	25,000,000
Available-for-sale securities		619,848,000	518,848,000
Held-to-maturity Securities		74,231,000
Held-to-maturity Securities, Fair Value			85,208,000
Loans held for sale		1,175,000	968,000
Loans net of allowance for loan losses		1,808,064,000	1,266,345,000
Interest receivable		10,553,000	8,085,000
Federal Reserve Bank stock		3,949,000	2,272,000
Federal Home Loan Bank stock		4,389,000	3,391,000
Deposits		2,329,887,000	1,732,568,000
Securities sold under agreements to repurchase		185,763,000	128,842,000
Interest payable		535,000	356,000
Federal Home Loan Bank borrowings		40,094,000	20,000,000
Junior subordinated debentures		23,917,000	20,620,000
Fair Value
Financial Assets [Abstract]
Cash and due from banks		137,002,000	115,292,000
Federal funds sold		38,900,000	492,000
Certificates of deposit investments		14,651,000	25,056,000
Available-for-sale securities		619,848,000	518,848,000
Held-to-maturity Securities, Fair Value		73,096,000	85,737,000
Loans held for sale		1,175,000	968,000
Loans net of allowance for loan losses		1,795,764,000	1,265,126,000
Interest receivable		10,553,000	8,085,000
Federal Reserve Bank stock		3,949,000	2,272,000
Federal Home Loan Bank stock		4,389,000	3,391,000
Deposits		2,331,725,000	1,732,463,000
Securities sold under agreements to repurchase		185,766,000	128,843,000
Interest payable		535,000	356,000
Federal Home Loan Bank borrowings		40,318,000	20,422,000
Junior subordinated debentures		17,068,000	13,207,000
Fair Value, Measurements, Nonrecurring [Member] | Carrying Amount
Foreclosed Assets Held for Sale [Abstract]
Other real estate owned		1,982,000	477,000
Fair Value, Measurements, Nonrecurring [Member] | Fair Value
Foreclosed Assets Held for Sale [Abstract]
Other real estate owned		173,000	423,000
Fair Value, Inputs, Level 1 [Member]
Financial Assets [Abstract]
Cash and due from banks		137,002,000	115,292,000
Federal funds sold		38,900,000	492,000
Certificates of deposit investments		0	0
Available-for-sale securities		144,000	64,000
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
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		14,651,000	25,056,000
Available-for-sale securities		618,052,000	516,878,000
Held-to-maturity Securities, Fair Value		73,096,000	85,737,000
Loans held for sale		1,175,000	968,000
Loans net of allowance for loan losses		0	0
Interest receivable		10,553,000	8,085,000
Federal Reserve Bank stock		3,949,000	2,272,000
Federal Home Loan Bank stock		4,389,000	3,391,000
Deposits		1,976,806,000	1,489,130,000
Securities sold under agreements to repurchase		185,766,000	128,843,000
Interest payable		535,000	356,000
Federal Home Loan Bank borrowings		40,318,000	20,422,000
Junior subordinated debentures		17,068,000	13,207,000
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		1,652,000	1,906,000
Loans held for sale		0	0
Loans net of allowance for loan losses		1,795,764,000	1,265,126,000
Interest receivable		0	0
Federal Reserve Bank stock		0	0
Federal Home Loan Bank stock		0	0
Deposits		354,919,000	243,333,000
Securities sold under agreements to repurchase		0	0
Interest payable		0	0
Federal Home Loan Bank borrowings		0	0
Junior subordinated debentures		$ 0	$ 0
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%	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)		13.60%	11.40%
Cumulative projected prepayments (in hundredths)		22.40%	23.60%
Probability of default (in hundredths)		0.50%	0.40%
Projected cures given deferral (in hundredths)		0.00%	100.00%
Loss severity		97.60%	97.30%
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 Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Nonrecurring		$ 6,938,000	$ 294,000
Impaired loans (collateral dependent) | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Nonrecurring		0	0
Impaired loans (collateral dependent) | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Nonrecurring		$ 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 Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Nonrecurring		$ 6,938,000	$ 294,000
Foreclosed assets held for sale | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Nonrecurring		173,000	423,000
Foreclosed assets held for sale | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Nonrecurring		0	0
Foreclosed assets held for sale | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Nonrecurring		$ 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 Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Nonrecurring		$ 173,000	$ 423,000

[1] Every five years