Credit Quality and Nonperforming Assets - Past Due and Nonaccrual Loans (Parenthetical) (Details) - USD ($)	Mar. 31, 2019		Dec. 31, 2018		Mar. 31, 2018
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due And Accruing	$ 7,488,000		$ 7,480,000
90 Days Or More Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due And Accruing	$ 2,947,000	[1]	1,903,000	[2]
90 Days Or More Past Due [Member] | 1-4 Family - Closed-End [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due And Accruing			$ 0		$ 0

[1] As of March 31, 2018 there were no loans over 90 days past due and still accruing.

[2] As of December 31, 2018 there were no loans over 90 days past due and still accruing.