Fair Value (Assets and Liabilities Measured at Fair Value on Non-Recurring Basis) (Details) - Fair Value, Measurements, Nonrecurring - Impaired Loans - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Commercial and Industrial Loans and Leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	$ 79	$ 15
Commercial Real Estate Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	545	960
Agricultural Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	449
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial and Industrial Loans and Leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial Real Estate Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Agricultural Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	0
Significant Other Observable Inputs (Level 2) | Commercial and Industrial Loans and Leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	0	0
Significant Other Observable Inputs (Level 2) | Commercial Real Estate Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	0	0
Significant Other Observable Inputs (Level 2) | Agricultural Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	0
Significant Unobservable Inputs (Level 3) | Commercial and Industrial Loans and Leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	79	15
Significant Unobservable Inputs (Level 3) | Commercial Real Estate Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	545	$ 960
Significant Unobservable Inputs (Level 3) | Agricultural Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	$ 449