Fair Value Measurement (Fair Value Measurements, Nonrecurring) (Details) - Nonrecurring [Member] - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Impaired Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	$ 4,689	$ 6,090
Foreclosed Assets Held for Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	29
Mortgage Servicing Rights [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	111	126
Level 3 [Member] | Impaired Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	4,689	6,090
Level 3 [Member] | Foreclosed Assets Held for Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	29
Level 3 [Member] | Mortgage Servicing Rights [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	$ 111	$ 126