Loans and Leases - Credit Risk Profile by Internally Assigned Grade (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	$ 3,427,154	$ 3,285,858
Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1,657,436	1,523,377
Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	207,351	218,275
Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	494,355	458,886
Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	181,078	212,454
Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	695,584	719,312
Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	46,814	38,153
Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	144,536	115,401
Pass
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	3,374,840	3,219,948
Pass | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1,635,068	1,490,862
Pass | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	203,037	216,794
Pass | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	490,789	454,469
Pass | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	171,353	193,227
Pass | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	684,444	711,145
Pass | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	46,588	38,153
Pass | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	143,561	115,298
Special Mention
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	4,306	18,239
Special Mention | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	631	13,448
Special Mention | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Special Mention | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Special Mention | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	938	3,902
Special Mention | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	2,737	889
Special Mention | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Special Mention | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Substandard
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	46,909	45,533
Substandard | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	20,639	18,194
Substandard | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	4,314	1,481
Substandard | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	3,566	4,417
Substandard | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	8,787	15,325
Substandard | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	8,402	6,013
Substandard | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	226	0
Substandard | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	975	103
Doubtful
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1,099	2,138
Doubtful | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1,098	873
Doubtful | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Doubtful | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Doubtful | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Doubtful | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1	1,265
Doubtful | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Doubtful | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Total
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	3,427,154	3,285,858
Total | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1,657,436	1,523,377
Total | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	207,351	218,275
Total | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	494,355	458,886
Total | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	181,078	212,454
Total | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	695,584	719,312
Total | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	46,814	38,153
Total | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	144,536	115,401
Originated
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	2,885,251	2,487,296
Originated | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1,327,822	1,122,327
Originated | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	181,506	183,283
Originated | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	411,022	360,935
Originated | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	174,592	128,266
Originated | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	624,643	589,304
Originated | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	44,099	35,146
Originated | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	121,567	68,035
Originated | Pass
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	2,856,184	2,471,897
Originated | Pass | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1,321,973	1,114,171
Originated | Pass | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	177,916	182,062
Originated | Pass | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	408,095	359,430
Originated | Pass | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	167,272	126,260
Originated | Pass | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	615,817	586,896
Originated | Pass | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	43,936	35,146
Originated | Pass | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	121,175	67,932
Originated | Special Mention
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	4,080	664
Originated | Special Mention | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	631	0
Originated | Special Mention | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Originated | Special Mention | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Originated | Special Mention | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	938	0
Originated | Special Mention | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	2,511	664
Originated | Special Mention | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Originated | Special Mention | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Originated | Substandard
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	24,986	14,380
Originated | Substandard | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	5,218	8,156
Originated | Substandard | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	3,590	1,221
Originated | Substandard | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	2,927	1,505
Originated | Substandard | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	6,382	2,006
Originated | Substandard | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	6,314	1,389
Originated | Substandard | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	163	0
Originated | Substandard | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	392	103
Originated | Doubtful
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1	355
Originated | Doubtful | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Originated | Doubtful | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Originated | Doubtful | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Originated | Doubtful | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Originated | Doubtful | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1	355
Originated | Doubtful | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Originated | Doubtful | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Originated | Total
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	2,885,251	2,487,296
Originated | Total | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1,327,822	1,122,327
Originated | Total | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	181,506	183,283
Originated | Total | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	411,022	360,935
Originated | Total | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	174,592	128,266
Originated | Total | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	624,643	589,304
Originated | Total | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	44,099	35,146
Originated | Total | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	121,567	68,035
Acquired | Pass
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	518,656	748,051
Acquired | Pass | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	313,095	376,691
Acquired | Pass | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	25,121	34,732
Acquired | Pass | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	82,694	95,039
Acquired | Pass | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	4,081	66,967
Acquired | Pass | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	68,627	124,249
Acquired | Pass | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	2,652	3,007
Acquired | Pass | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	22,386	47,366
Acquired | Special Mention
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	226	17,575
Acquired | Special Mention | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	13,448
Acquired | Special Mention | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Acquired | Special Mention | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Acquired | Special Mention | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	3,902
Acquired | Special Mention | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	226	225
Acquired | Special Mention | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Acquired | Special Mention | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Acquired | Substandard
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	21,923	31,153
Acquired | Substandard | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	15,421	10,038
Acquired | Substandard | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	724	260
Acquired | Substandard | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	639	2,912
Acquired | Substandard | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	2,405	13,319
Acquired | Substandard | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	2,088	4,624
Acquired | Substandard | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	63	0
Acquired | Substandard | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	583	0
Acquired | Doubtful
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1,098	1,783
Acquired | Doubtful | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	1,098	873
Acquired | Doubtful | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Acquired | Doubtful | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Acquired | Doubtful | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Acquired | Doubtful | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	910
Acquired | Doubtful | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Acquired | Doubtful | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	0	0
Acquired | Total
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	541,903	798,562
Acquired | Total | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	329,614	401,050
Acquired | Total | Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	25,845	34,992
Acquired | Total | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	83,333	97,951
Acquired | Total | Construction
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	6,486	84,188
Acquired | Total | Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	70,941	130,008
Acquired | Total | Consumer
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	2,715	3,007
Acquired | Total | Leases
Loans and Leases Receivable Disclosure [Line Items]
Portfolio loans and leases	$ 22,969	$ 47,366