Loans and Allowance for Loan Losses (Credit Risk Exposure Indicators by Portfolio Segment) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans:	$ 2,782,439	$ 2,594,564	$ 2,490,206
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	2,374,582	2,173,031
Performing Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans:	339,876	345,615
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	22,784	13,966
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans:	43,546	58,872
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:		1,456
Nonperforming Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans:	1,651	1,624
Residential real estate loans
Financing Receivable, Recorded Investment [Line Items]
Loans:	858,369	802,494	820,617
Residential real estate loans | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	846,394	789,554
Residential real estate loans | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	922	2,387
Residential real estate loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans:	11,053	10,553
Commercial real estate loans
Financing Receivable, Recorded Investment [Line Items]
Loans:	1,164,023	1,050,780	927,951
Commercial real estate loans | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	1,130,235	1,003,386
Commercial real estate loans | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	9,154	5,724
Commercial real estate loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans:	24,634	41,670
Commercial loans
Financing Receivable, Recorded Investment [Line Items]
Loans:	373,400	333,639	297,721
Commercial loans | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	354,904	321,148
Commercial loans | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	12,517	5,598
Commercial loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans:	5,979	5,437
Commercial loans | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:		1,456
Home equity loans
Financing Receivable, Recorded Investment [Line Items]
Loans:	323,378	329,907	348,634
Home equity loans | Performing Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans:	321,727	328,287
Home equity loans | Nonperforming Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans:	1,651	1,620
Consumer loans
Financing Receivable, Recorded Investment [Line Items]
Loans:	18,149	17,332	17,953
Consumer loans | Performing Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans:	18,149	17,328
Consumer loans | Nonperforming Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans:		4
HPFC Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	45,120	60,412	$ 77,330
HPFC Portfolio Segment [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	43,049	58,943
HPFC Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	191	257
HPFC Portfolio Segment [Member] | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans:	$ 1,880	$ 1,212