Loans and Allowance for Credit Losses (Impaired Financing Receivables by Loan Class) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	$ 20,764		$ 20,764		$ 26,160
Recorded investment with no allowance	12,717		12,717		10,896
Recorded investment with an allowance	7,065		7,065		11,076
Related allowance	875		875		2,141
Average recorded investment	19,129	$ 25,052	20,239	$ 26,148
Interest income recognized			344	350
Impaired Nonaccrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	7,271		7,271		13,160
Recorded investment with no allowance	3,335		3,335		3,015
Recorded investment with an allowance	2,954		2,954		5,957
Related allowance	571		571		1,904
Average recorded investment	6,563	11,757	7,661	11,945
Impaired Accruing Restructured Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	13,493		13,493		13,000
Recorded investment with no allowance	9,382		9,382		7,881
Recorded investment with an allowance	4,111		4,111		5,119
Related allowance	304		304		237
Average recorded investment	12,566	13,295	12,578	14,203
Interest income recognized			344	350
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	7,361		7,361		7,888
Recorded investment with no allowance	4,629		4,629		4,786
Recorded investment with an allowance	2,561		2,561		2,992
Related allowance	251		251		317
Average recorded investment	6,531	8,112	7,193	8,306
Interest income recognized			117	149
Residential Portfolio Segment [Member] | Impaired Nonaccrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	2,736		2,736		4,013
Recorded investment with no allowance	2,439		2,439		1,957
Recorded investment with an allowance	126		126		1,946
Related allowance	23		23		166
Average recorded investment	2,840	4,012	3,573	3,406
Residential Portfolio Segment [Member] | Impaired Accruing Restructured Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	4,625		4,625		3,875
Recorded investment with no allowance	2,190		2,190		2,829
Recorded investment with an allowance	2,435		2,435		1,046
Related allowance	228		228		151
Average recorded investment	3,691	4,100	3,620	4,900
Interest income recognized			117	149
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	5,910		5,910		6,737
Recorded investment with no allowance	4,524		4,524		2,532
Recorded investment with an allowance	741		741		3,556
Related allowance	35		35		185
Average recorded investment	5,330	7,159	5,499	7,402
Interest income recognized			145	127
Commercial Real Estate Portfolio Segment [Member] | Impaired Nonaccrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	1,075		1,075		1,801
Recorded investment with no allowance	430		430		959
Recorded investment with an allowance					193
Related allowance					117
Average recorded investment	489	2,177	627	2,265
Commercial Real Estate Portfolio Segment [Member] | Impaired Accruing Restructured Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	4,835		4,835		4,936
Recorded investment with no allowance	4,094		4,094		1,573
Recorded investment with an allowance	741		741		3,363
Related allowance	35		35		68
Average recorded investment	4,841	4,982	4,872	5,137
Interest income recognized			145	127
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	425		425
Recorded investment with no allowance	341		341
Average recorded investment	344	108	153	143
Commercial Portfolio Segment [Member] | Impaired Nonaccrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	425		425
Recorded investment with no allowance	341		341
Average recorded investment	344	108	153	143
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance					99
Recorded investment with no allowance					99
Average recorded investment		99	55	109
Consumer Portfolio Segment [Member] | Impaired Nonaccrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance					99
Recorded investment with no allowance					99
Average recorded investment		99	55	109
Construction Loans [Member] | Commercial and Residential Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	7,068		7,068		11,436
Recorded investment with no allowance	3,223		3,223		3,479
Recorded investment with an allowance	3,763		3,763		4,528
Related allowance	589		589		1,639
Average recorded investment	6,924	9,574	7,339	10,188
Interest income recognized			82	74
Construction Loans [Member] | Commercial and Residential Real Estate Portfolio Segment [Member] | Impaired Nonaccrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	3,035		3,035		7,247
Recorded investment with no allowance	125		125
Recorded investment with an allowance	2,828		2,828		3,818
Related allowance	548		548		1,621
Average recorded investment	2,890	5,361	3,253	6,022
Construction Loans [Member] | Commercial and Residential Real Estate Portfolio Segment [Member] | Impaired Accruing Restructured Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	4,033		4,033		4,189
Recorded investment with no allowance	3,098		3,098		3,479
Recorded investment with an allowance	935		935		710
Related allowance	41		41		$ 18
Average recorded investment	$ 4,034	$ 4,213	4,086	4,166
Interest income recognized			$ 82	$ 74