Allowance For Loan Loss - Adversely Classified Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Gross loans	$ 2,066,903	$ 2,024,798
Adversely classified loans to total loans	1.55%	1.70%
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Gross loans	$ 1,064,661	$ 1,038,082
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Gross loans	507,612	490,799
Commercial construction
Financing Receivable, Recorded Investment [Line Items]
Gross loans	209,701	213,447
Residential
Financing Receivable, Recorded Investment [Line Items]
Gross loans	183,490	180,560
Home Equity
Financing Receivable, Recorded Investment [Line Items]
Gross loans	91,294	91,065
Consumer
Financing Receivable, Recorded Investment [Line Items]
Gross loans	10,145	10,845
Substandard
Financing Receivable, Recorded Investment [Line Items]
Gross loans	31,855	34,247
Substandard | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Gross loans	15,778	16,003
Substandard | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Gross loans	11,948	12,770
Substandard | Commercial construction
Financing Receivable, Recorded Investment [Line Items]
Gross loans	1,935	3,364
Substandard | Residential
Financing Receivable, Recorded Investment [Line Items]
Gross loans	1,397	1,414
Substandard | Home Equity
Financing Receivable, Recorded Investment [Line Items]
Gross loans	755	666
Substandard | Consumer
Financing Receivable, Recorded Investment [Line Items]
Gross loans	42	30
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Gross loans	54	99
Doubtful | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Gross loans	0	0
Doubtful | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Gross loans	54	99
Doubtful | Commercial construction
Financing Receivable, Recorded Investment [Line Items]
Gross loans	0	0
Doubtful | Residential
Financing Receivable, Recorded Investment [Line Items]
Gross loans	0	0
Doubtful | Home Equity
Financing Receivable, Recorded Investment [Line Items]
Gross loans	0	0
Doubtful | Consumer
Financing Receivable, Recorded Investment [Line Items]
Gross loans	0	0
Loss
Financing Receivable, Recorded Investment [Line Items]
Gross loans	2	2
Loss | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Gross loans	0	0
Loss | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Gross loans	2	2
Loss | Commercial construction
Financing Receivable, Recorded Investment [Line Items]
Gross loans	0	0
Loss | Residential
Financing Receivable, Recorded Investment [Line Items]
Gross loans	0	0
Loss | Home Equity
Financing Receivable, Recorded Investment [Line Items]
Gross loans	0	0
Loss | Consumer
Financing Receivable, Recorded Investment [Line Items]
Gross loans	0	0
Not Adversely Classified
Financing Receivable, Recorded Investment [Line Items]
Gross loans	2,034,992	1,990,450
Not Adversely Classified | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Gross loans	1,048,883	1,022,079
Not Adversely Classified | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Gross loans	495,608	477,928
Not Adversely Classified | Commercial construction
Financing Receivable, Recorded Investment [Line Items]
Gross loans	207,766	210,083
Not Adversely Classified | Residential
Financing Receivable, Recorded Investment [Line Items]
Gross loans	182,093	179,146
Not Adversely Classified | Home Equity
Financing Receivable, Recorded Investment [Line Items]
Gross loans	90,539	90,399
Not Adversely Classified | Consumer
Financing Receivable, Recorded Investment [Line Items]
Gross loans	$ 10,103	$ 10,815