Long-Term Borrowings (Narrative) (Details)		12 Months Ended
	Mar. 06, 2015 USD ($) semi_annual_period	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Long-term borrowings
Debt Instrument, Interest Rate, Stated Percentage		0.00%	0.00%
Total Risk-Based Capital Ratio Minimum Under Debt Covenant		12.50%
Nonperforming Assets to Tangible Capital plus Allowance for Loan Losses Maximum Under Debt Covenant		20.00%
Allowance for Loan Losses to Nonperforming Loans Minimum Under Debt Covenant		70.00%
Fixed charge coverage ratio minimum required by debt covenant		125.00%
Callable national market repurchase agreements, Weighted-Average Rate		3.63%	3.63%
Extinguishment of Debt, Amount		$ 20,000,000
Net loss on other transactions		(707,000)	$ (520,000)	$ 67,000
Junior subordinated debt securities		6,924,000	6,736,000
Interest rate on capital securities	1.50%
Revolving Line of Credit		15,000,000	15,000,000
Line of Credit Facility, Commitment Fee Amount		$ 70,600
Line of Credit Facility, Commitment Fee Percentage		0.47%
Maximum aggregate indebtedness under debt covenants		$ 10,000,000
Maximum material transaction amount under debt covenant		10,000,000
Restructuring Charges		700,000
Long-term borrowings		$ 145,155,000	113,670,000
Long-term Debt [Member]
Long-term borrowings
Debt, Weighted Average Interest Rate		2.97%
Minimum
Long-term borrowings
Repurchase agreements, maturities period		5 years
Repurchase agreements, call option features at buyer discretion, initial call period		3 months
Derivative, Fixed Interest Rate		1.49%
Maximum
Long-term borrowings
Repurchase agreements, maturities period		10 years
Repurchase agreements, call option features at buyer discretion, initial call period		5 years
Distributions on Capital Securities, Deferred, Number of Consecutive Semiannual Periods | semi_annual_period	20
Derivative, Fixed Interest Rate		1.83%
FHLB Advances [Member]
Long-term borrowings
Long-term borrowings		$ 35,000,000
FHLB Advances
Long-term borrowings
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum		1.08%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum		1.40%
FHLB putable non-amortizing, fixed-rate advances
Long-term borrowings
Long-term Federal Home Loan Bank Advances		$ 70,000,000	$ 50,000,000
FHLB advances, Weighted-Average Rate		2.49%	3.32%
FHLB putable non-amortizing, fixed-rate advances | Minimum
Long-term borrowings
FHLB advances, maturities period		2 years
FHLB putable non-amortizing, fixed-rate advances | Maximum
Long-term borrowings
FHLB advances, maturities period		11 years
FHLB amortizing, fixed-rate advances | Minimum
Long-term borrowings
FHLB advances,fixed rate intial period		3 months
FHLB amortizing, fixed-rate advances | Maximum
Long-term borrowings
FHLB advances,fixed rate intial period		5 years
Junior subordinated debt securities
Long-term borrowings
Long-term Federal Home Loan Bank Advances		$ 28,282,000	$ 16,934,000
FHLB advances, Weighted-Average Rate		2.01%	2.69%
Junior subordinated debt securities | Minimum
Long-term borrowings
FHLB advances, maturities period		2 years
Junior subordinated debt securities | Maximum
Long-term borrowings
FHLB advances, maturities period		15 years
Long-term Debt [Member]
Long-term borrowings
Debt, Weighted Average Interest Rate		2.17%
NB&T Financial Group, Inc. [Member]
Long-term borrowings
Junior subordinated debt securities	$ 6,600,000
Interest Rate Swap
Long-term borrowings
Long-term borrowings		$ 40,000,000
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum		3.57%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum		3.92%