Allowance for Credit Losses and Credit Quality Information - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	$ 9,014,677	$ 8,464,562
Total Commercial | Commercial and industrial(1)
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,336,436
2019	535,401
2018	383,110
2017	216,287
2016	114,764
Prior	177,504
Revolving loans amortized cost basis	6,245
Revolving loans converted to term	179,556
Total Loans	2,949,303	2,235,428
Gross loans	2,700,418	2,046,798
Total Commercial | Commercial and industrial(1) | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,250,528
2019	448,704
2018	296,594
2017	157,359
2016	97,036
Prior	125,361
Revolving loans amortized cost basis	6,182
Revolving loans converted to term	136,110
Total Loans	2,517,874
Total Commercial | Commercial and industrial(1) | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	3,040
2019	26,470
2018	28,636
2017	8,482
2016	2,577
Prior	16,993
Revolving loans amortized cost basis	0
Revolving loans converted to term	34,403
Total Loans	120,601
Total Commercial | Commercial and industrial(1) | Substandard or Lower
Financing Receivable, Credit Quality Indicator [Line Items]
2020	82,868
2019	60,227
2018	57,880
2017	50,446
2016	15,151
Prior	35,150
Revolving loans amortized cost basis	63
Revolving loans converted to term	9,043
Total Loans	310,828
Total Commercial | Owner-occupied commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2020	225,393
2019	245,077
2018	107,625
2017	173,364
2016	139,603
Prior	292,414
Revolving loans amortized cost basis	0
Revolving loans converted to term	149,251
Total Loans	1,332,727	1,296,466
Gross loans	1,332,727	1,296,466
Total Commercial | Owner-occupied commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	220,165
2019	225,766
2018	90,515
2017	135,903
2016	123,897
Prior	271,086
Revolving loans amortized cost basis	0
Revolving loans converted to term	123,194
Total Loans	1,190,526
Total Commercial | Owner-occupied commercial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,525
2019	5,885
2018	1,838
2017	17,578
2016	4,125
Prior	1,997
Revolving loans amortized cost basis	0
Revolving loans converted to term	14,467
Total Loans	47,415
Total Commercial | Owner-occupied commercial | Substandard or Lower
Financing Receivable, Credit Quality Indicator [Line Items]
2020	3,703
2019	13,426
2018	15,272
2017	19,883
2016	11,581
Prior	19,331
Revolving loans amortized cost basis	0
Revolving loans converted to term	11,590
Total Loans	94,786
Total Commercial | Commercial mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
2020	414,259
2019	310,180
2018	264,939
2017	281,028
2016	259,296
Prior	406,280
Revolving loans amortized cost basis	0
Revolving loans converted to term	150,080
Total Loans	2,086,062	2,222,976
Gross loans	2,086,062	2,222,976
Total Commercial | Commercial mortgages | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	379,592
2019	283,004
2018	240,924
2017	257,809
2016	254,780
Prior	375,473
Revolving loans amortized cost basis	0
Revolving loans converted to term	148,210
Total Loans	1,939,792
Total Commercial | Commercial mortgages | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	8,324
2019	1,774
2018	21,762
2017	21,269
2016	1,274
Prior	6,507
Revolving loans amortized cost basis	0
Revolving loans converted to term	1,870
Total Loans	62,780
Total Commercial | Commercial mortgages | Substandard or Lower
Financing Receivable, Credit Quality Indicator [Line Items]
2020	26,343
2019	25,402
2018	2,253
2017	1,950
2016	3,242
Prior	24,300
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Total Loans	83,490
Total Commercial | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
2020	189,257
2019	223,604
2018	208,981
2017	14,929
2016	7,414
Prior	3,724
Revolving loans amortized cost basis	0
Revolving loans converted to term	68,366
Total Loans	716,275	581,082
Gross loans	716,275	581,082
Total Commercial | Construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	189,257
2019	214,956
2018	208,981
2017	11,414
2016	7,414
Prior	3,645
Revolving loans amortized cost basis	0
Revolving loans converted to term	66,018
Total Loans	701,685
Total Commercial | Construction | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	3,515
2016	0
Prior	0
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Total Loans	3,515
Total Commercial | Construction | Substandard or Lower
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	8,648
2018	0
2017	0
2016	0
Prior	79
Revolving loans amortized cost basis	0
Revolving loans converted to term	2,348
Total Loans	11,075
Total Commercial | Paycheck Protection Program, CARES Act
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans	751,200
Residential
Financing Receivable, Credit Quality Indicator [Line Items]
2020	42,588
2019	26,309
2018	71,410
2017	85,277
2016	149,926
Prior	388,883
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Total Loans	764,393	999,879
Gross loans	774,455	1,016,500
Residential | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
2020	42,475
2019	26,309
2018	71,410
2017	85,277
2016	149,643
Prior	383,358
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Total Loans	758,472
Residential | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
2020	113
2019	0
2018	0
2017	0
2016	283
Prior	5,525
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Total Loans	5,921
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	235,948
2019	134,064
2018	251,723
2017	63,945
2016	44,700
Prior	53,717
Revolving loans amortized cost basis	373,238
Revolving loans converted to term	8,582
Total Loans	1,165,917	1,128,731
Gross loans	1,165,917	$ 1,128,731
Consumer | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
2020	235,948
2019	134,064
2018	251,087
2017	63,713
2016	44,700
Prior	53,717
Revolving loans amortized cost basis	371,842
Revolving loans converted to term	8,287
Total Loans	1,163,358
Consumer | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	636
2017	232
2016	0
Prior	0
Revolving loans amortized cost basis	1,396
Revolving loans converted to term	295
Total Loans	$ 2,559