Loans and Leases - Past Due Loans and Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	$ 5,465	$ 7,959
Loans and leases, current	3,408,869	3,269,320
Loans and leases, accruing	3,414,334	3,277,279
Non-accrual loans and leases	12,820	8,579
Portfolio loans and leases	3,427,154	3,285,858
Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	3,872	3,081
Loans and leases, current	2,872,318	2,480,470
Loans and leases, accruing	2,876,190	2,483,551
Non-accrual loans and leases	9,061	3,745
Portfolio loans and leases	2,885,251	2,487,296
Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	1,593	4,878
Loans and leases, current	536,551	788,850
Loans and leases, accruing	538,144	793,728
Non-accrual loans and leases	3,759	4,834
Portfolio loans and leases	541,903	798,562
Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	4,199	4,979
Financing Receivables, 30 to 59 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	3,051	2,587
Financing Receivables, 30 to 59 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	1,148	2,392
Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	1,266	2,980
Financing Receivables, 60 to 89 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	821	494
Financing Receivables, 60 to 89 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	445	2,486
Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Commercial mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	1,072	3,794
Loans and leases, current	1,653,796	1,518,711
Loans and leases, accruing	1,654,868	1,522,505
Non-accrual loans and leases	2,568	872
Portfolio loans and leases	1,657,436	1,523,377
Commercial mortgage | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	1,067	1,336
Loans and leases, current	1,326,320	1,120,901
Loans and leases, accruing	1,327,387	1,122,237
Non-accrual loans and leases	435	90
Portfolio loans and leases	1,327,822	1,122,327
Commercial mortgage | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	5	2,458
Loans and leases, current	327,476	397,810
Loans and leases, accruing	327,481	400,268
Non-accrual loans and leases	2,133	782
Portfolio loans and leases	329,614	401,050
Commercial mortgage | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	821	1,366
Commercial mortgage | Financing Receivables, 30 to 59 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	816	1,255
Commercial mortgage | Financing Receivables, 30 to 59 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	5	111
Commercial mortgage | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	251	2,428
Commercial mortgage | Financing Receivables, 60 to 89 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	251	81
Commercial mortgage | Financing Receivables, 60 to 89 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	2,347
Commercial mortgage | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Commercial mortgage | Financing Receivables, Equal to Greater than 90 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Commercial mortgage | Financing Receivables, Equal to Greater than 90 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Home equity lines and loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	92	348
Loans and leases, current	203,643	216,446
Loans and leases, accruing	203,735	216,794
Non-accrual loans and leases	3,616	1,481
Portfolio loans and leases	207,351	218,275
Home equity lines and loans | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	25	26
Loans and leases, current	177,891	182,036
Loans and leases, accruing	177,916	182,062
Non-accrual loans and leases	3,590	1,221
Portfolio loans and leases	181,506	183,283
Home equity lines and loans | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	67	322
Loans and leases, current	25,752	34,410
Loans and leases, accruing	25,819	34,732
Non-accrual loans and leases	26	260
Portfolio loans and leases	25,845	34,992
Home equity lines and loans | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	92	338
Home equity lines and loans | Financing Receivables, 30 to 59 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	25	26
Home equity lines and loans | Financing Receivables, 30 to 59 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	67	312
Home equity lines and loans | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	10
Home equity lines and loans | Financing Receivables, 60 to 89 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Home equity lines and loans | Financing Receivables, 60 to 89 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	10
Home equity lines and loans | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Home equity lines and loans | Financing Receivables, Equal to Greater than 90 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Home equity lines and loans | Financing Receivables, Equal to Greater than 90 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	2,548	1,465
Loans and leases, current	488,355	453,004
Loans and leases, accruing	490,903	454,469
Non-accrual loans and leases	3,452	4,417
Portfolio loans and leases	494,355	458,886
Residential mortgage | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	1,545	721
Loans and leases, current	406,664	358,709
Loans and leases, accruing	408,209	359,430
Non-accrual loans and leases	2,813	1,505
Portfolio loans and leases	411,022	360,935
Residential mortgage | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	1,003	744
Loans and leases, current	81,691	94,295
Loans and leases, accruing	82,694	95,039
Non-accrual loans and leases	639	2,912
Portfolio loans and leases	83,333	97,951
Residential mortgage | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	2,330	1,386
Residential mortgage | Financing Receivables, 30 to 59 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	1,545	721
Residential mortgage | Financing Receivables, 30 to 59 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	785	665
Residential mortgage | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	218	79
Residential mortgage | Financing Receivables, 60 to 89 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Residential mortgage | Financing Receivables, 60 to 89 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	218	79
Residential mortgage | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Residential mortgage | Financing Receivables, Equal to Greater than 90 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Residential mortgage | Financing Receivables, Equal to Greater than 90 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Loans and leases, current	181,078	212,454
Loans and leases, accruing	181,078	212,454
Non-accrual loans and leases	0	0
Portfolio loans and leases	181,078	212,454
Construction | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Loans and leases, current	174,592	128,266
Loans and leases, accruing	174,592	128,266
Non-accrual loans and leases	0	0
Portfolio loans and leases	174,592	128,266
Construction | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Loans and leases, current	6,486	84,188
Loans and leases, accruing	6,486	84,188
Non-accrual loans and leases	0	0
Portfolio loans and leases	6,486	84,188
Construction | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Construction | Financing Receivables, 30 to 59 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Construction | Financing Receivables, 30 to 59 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Construction | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Construction | Financing Receivables, 60 to 89 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Construction | Financing Receivables, 60 to 89 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Construction | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Construction | Financing Receivables, Equal to Greater than 90 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Construction | Financing Receivables, Equal to Greater than 90 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	612	944
Loans and leases, current	692,871	716,662
Loans and leases, accruing	693,483	717,606
Non-accrual loans and leases	2,101	1,706
Portfolio loans and leases	695,584	719,312
Commercial and industrial | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	612	675
Loans and leases, current	622,245	587,803
Loans and leases, accruing	622,857	588,478
Non-accrual loans and leases	1,786	826
Portfolio loans and leases	624,643	589,304
Commercial and industrial | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	269
Loans and leases, current	70,626	128,859
Loans and leases, accruing	70,626	129,128
Non-accrual loans and leases	315	880
Portfolio loans and leases	70,941	130,008
Commercial and industrial | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	280	658
Commercial and industrial | Financing Receivables, 30 to 59 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	280	439
Commercial and industrial | Financing Receivables, 30 to 59 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	219
Commercial and industrial | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	332	286
Commercial and industrial | Financing Receivables, 60 to 89 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	332	236
Commercial and industrial | Financing Receivables, 60 to 89 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	50
Commercial and industrial | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Commercial and industrial | Financing Receivables, Equal to Greater than 90 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Commercial and industrial | Financing Receivables, Equal to Greater than 90 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	40	1,106
Loans and leases, current	46,666	37,047
Loans and leases, accruing	46,706	38,153
Non-accrual loans and leases	108	0
Portfolio loans and leases	46,814	38,153
Consumer | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	40	21
Loans and leases, current	44,014	35,125
Loans and leases, accruing	44,054	35,146
Non-accrual loans and leases	45	0
Portfolio loans and leases	44,099	35,146
Consumer | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	1,085
Loans and leases, current	2,652	1,922
Loans and leases, accruing	2,652	3,007
Non-accrual loans and leases	63	0
Portfolio loans and leases	2,715	3,007
Consumer | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	35	1,106
Consumer | Financing Receivables, 30 to 59 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	35	21
Consumer | Financing Receivables, 30 to 59 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	1,085
Consumer | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	5	0
Consumer | Financing Receivables, 60 to 89 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	5	0
Consumer | Financing Receivables, 60 to 89 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Consumer | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Consumer | Financing Receivables, Equal to Greater than 90 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Consumer | Financing Receivables, Equal to Greater than 90 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	1,101	302
Loans and leases, current	142,460	114,996
Loans and leases, accruing	143,561	115,298
Non-accrual loans and leases	975	103
Portfolio loans and leases	144,536	115,401
Leases | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	583	302
Loans and leases, current	120,592	67,630
Loans and leases, accruing	121,175	67,932
Non-accrual loans and leases	392	103
Portfolio loans and leases	121,567	68,035
Leases | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	518	0
Loans and leases, current	21,868	47,366
Loans and leases, accruing	22,386	47,366
Non-accrual loans and leases	583	0
Portfolio loans and leases	22,969	47,366
Leases | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	641	125
Leases | Financing Receivables, 30 to 59 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	350	125
Leases | Financing Receivables, 30 to 59 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	291	0
Leases | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	460	177
Leases | Financing Receivables, 60 to 89 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	233	177
Leases | Financing Receivables, 60 to 89 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	227	0
Leases | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Leases | Financing Receivables, Equal to Greater than 90 Days Past Due | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Leases | Financing Receivables, Equal to Greater than 90 Days Past Due | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, past due	0	0
Administratively Delinquent
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, current	3,200	4,100
Administratively Delinquent | Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, current	2,000	4,000
Administratively Delinquent | Acquired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases, current	$ 1,200	$ 102