Long-Term Borrowings (Narrative) (Details)		12 Months Ended
	Mar. 06, 2015 USD ($) semi_annual_period	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Aug. 04, 2014 USD ($)	Dec. 18, 2012
Long-term borrowings
Proceeds from Issuance of Unsecured Debt		$ 24,000,000
Maturity Period of Long-Term Borrowing		5 years
Debt Instrument, Interest Rate, Stated Percentage		0.00%	3.50%		3.50%	3.80%
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%
Other Restricted Assets					$ 2,000,000
Callable national market repurchase agreements, Weighted-Average Rate		3.63%	3.63%
Net loss on other transactions		$ (520,000)	$ 67,000	$ 0
Junior subordinated debt securities		$ 6,736,000	0
Interest rate on capital securities	1.50%
Minimum
Long-term borrowings
Repurchase agreements, maturities period		5 years
Repurchase agreements, call option features at buyer discretion, initial call period		3 months
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
FHLB putable non-amortizing, fixed-rate advances
Long-term borrowings
Long-term Federal Home Loan Bank Advances		$ 50,000,000	$ 83,995,000
FHLB advances, Weighted-Average Rate		3.32%	3.30%
FHLB putable non-amortizing, fixed-rate advances | Minimum
Long-term borrowings
FHLB advances, maturities period		10 years
FHLB putable non-amortizing, fixed-rate advances | Maximum
Long-term borrowings
FHLB advances, maturities period		20 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		$ 16,934,000	$ 40,719,000
FHLB advances, Weighted-Average Rate		2.69%	2.13%
Junior subordinated debt securities | Minimum
Long-term borrowings
FHLB advances, maturities period		10 years
Junior subordinated debt securities | Maximum
Long-term borrowings
FHLB advances, maturities period		20 years
Repayments of debt [Member] | FHLB putable non-amortizing, fixed-rate advances
Long-term borrowings
Extinguishment of Debt, Amount		$ 52,100,000
FHLB advances, Weighted-Average Rate		1.49%
NB&T Financial Group, Inc. [Member]
Long-term borrowings
Junior subordinated debt securities	$ 6,600,000