Fair Value Measurement, Financial Assets Measured at Fair Value on Nonrecurring Basis (Details) - Fair Value on a Nonrecurring Basis [Member] - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Assets [Abstract]
Impaired loans, net	$ 2,689,000	$ 2,689,000	$ 5,087,000
Other real estate owned, net	1,356,000	$ 1,356,000	1,356,000
Level 3 [Member]
Financial Assets Recorded on a Nonrecurring Basis [Abstract]
Minimum age of appraisal of real estate property for fair value to be considered Level 3		1 year
Assets [Abstract]
Impaired loans, net	121,000	$ 121,000	46,000
Other real estate owned, net	1,356,000	1,356,000	1,356,000
Level 1 [Member]
Assets [Abstract]
Impaired loans, net	0	0	0
Other real estate owned, net	0	0	0
Level 2 [Member]
Assets [Abstract]
Impaired loans, net	2,568,000	2,568,000	5,041,000
Other real estate owned, net	0	0	$ 0
Mortgage Loans Held for Sale [Member]
Financial Assets Recorded on a Nonrecurring Basis [Abstract]
Nonrecurring fair value adjustments	$ 0	$ 0