Loans and Allowance for Credit Losses (Impaired Financing Receivables by Loan Class) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	$ 21,213		$ 21,213	$ 26,637
Recorded investment with no allowance	13,488		13,488	14,816
Recorded investment with an allowance	6,630		6,630	10,502
Related allowance	897		897	761
Average recorded investment	20,748	$ 15,983	22,127	16,605
Interest income recognized			232	100
Impaired Nonaccrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	13,625		13,625	17,974
Recorded investment with no allowance	9,390		9,390	12,039
Recorded investment with an allowance	3,140		3,140	4,616
Related allowance	690		690	541
Average recorded investment	13,173	6,822	14,372	6,355
Impaired Accruing Restructured Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	7,588		7,588	8,663
Recorded investment with no allowance	4,098		4,098	2,777
Recorded investment with an allowance	3,490		3,490	5,886
Related allowance	207		207	220
Average recorded investment	7,575	9,161	7,755	10,250
Interest income recognized			232	100
Impaired Accrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	712		712
Recorded investment with no allowance	584		584
Recorded investment with an allowance	128		128
Related allowance	58		58
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	6,435		6,435	8,735
Recorded investment with no allowance	1,749		1,749	4,045
Recorded investment with an allowance	4,379		4,379	4,508
Related allowance	441		441	301
Average recorded investment	6,694	6,419	7,097	6,186
Interest income recognized			130	46
Residential Portfolio Segment [Member] | Impaired Nonaccrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	2,366		2,366	4,281
Recorded investment with no allowance	489		489	2,605
Recorded investment with an allowance	1,570		1,570	1,494
Related allowance	256		256	118
Average recorded investment	2,642	1,710	2,904	1,573
Residential Portfolio Segment [Member] | Impaired Accruing Restructured Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	4,069		4,069	4,454
Recorded investment with no allowance	1,260		1,260	1,440
Recorded investment with an allowance	2,809		2,809	3,014
Related allowance	185		185	183
Average recorded investment	4,052	4,709	4,193	4,613
Interest income recognized			130	46
Residential Portfolio Segment [Member] | Impaired Accrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	584		584
Recorded investment with no allowance	584		584
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	14,310		14,310	14,187
Recorded investment with no allowance	11,696		11,696	10,593
Recorded investment with an allowance	1,943		1,943	2,939
Related allowance	452		452	104
Average recorded investment	13,700	6,049	13,232	5,937
Interest income recognized			93	41
Commercial Real Estate Portfolio Segment [Member] | Impaired Nonaccrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	10,834		10,834	10,029
Recorded investment with no allowance	8,901		8,901	9,307
Recorded investment with an allowance	1,262		1,262	67
Related allowance	430		430	67
Average recorded investment	10,221	1,742	9,717	1,438
Commercial Real Estate Portfolio Segment [Member] | Impaired Accruing Restructured Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	3,476		3,476	4,158
Recorded investment with no allowance	2,795		2,795	1,286
Recorded investment with an allowance	681		681	2,872
Related allowance	22		22	37
Average recorded investment	3,479	4,307	3,515	4,499
Interest income recognized			93	41
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	425		425	445
Recorded investment with an allowance	308		308	340
Related allowance	4		4	36
Average recorded investment	310	327	316	338
Commercial Portfolio Segment [Member] | Impaired Nonaccrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	425		425	445
Recorded investment with an allowance	308		308	340
Related allowance	4		4	36
Average recorded investment	310	327	316	338
Commercial Portfolio Segment [Member] | Impaired Accrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	128		128
Recorded investment with an allowance	128		128
Related allowance	58		58
Construction Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	43		43	3,270
Recorded investment with no allowance	43		43	178
Recorded investment with an allowance				2,715
Related allowance				320
Average recorded investment	44	3,188	1,482	4,144
Interest income recognized			9	13
Construction Loans [Member] | Impaired Nonaccrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance				3,219
Recorded investment with no allowance				127
Recorded investment with an allowance				2,715
Related allowance				320
Average recorded investment		3,043	1,435	3,006
Construction Loans [Member] | Impaired Accruing Restructured Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	43		43	51
Recorded investment with no allowance	43		43	51
Average recorded investment	$ 44	$ 145	47	1,138
Interest income recognized			$ 9	$ 13