Allowance for Credit Losses - Loan Balances by Year of Origination and Performing and Nonperforming Status (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	$ 287,583	$ 1,380,130
Year two	1,310,234	772,783
Year three	725,508	961,071
Year four	880,093	606,970
Year five	558,798	431,724
More than five years	1,854,855	1,591,979
Revolving	1,317,892	1,226,925
Revolving-Term	28,948	28,408
Total	6,963,911	6,999,990
Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	287,583	1,380,089
Year two	1,310,232	771,819
Year three	724,479	940,641
Year four	868,101	602,938
Year five	554,835	421,125
More than five years	1,822,457	1,564,501
Revolving	1,315,743	1,224,949
Revolving-Term	27,957	27,638
Total	6,911,387	6,933,699
Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	41
Year two	2	964
Year three	1,029	20,430
Year four	11,992	4,032
Year five	3,963	10,599
More than five years	32,398	27,478
Revolving	2,149	1,976
Revolving-Term	991	770
Total	52,524	66,291
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	5,331,863	5,406,584
Commercial | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	92,158	385,347
Year two	367,329	317,359
Year three	335,124	468,720
Year four	462,811	334,743
Year five	328,712	266,019
More than five years	1,083,184	881,391
Revolving	36,481	36,948
Revolving-Term	0	0
Total	2,705,799	2,690,528
Commercial | Commercial real estate | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	92,158	385,347
Year two	367,329	317,359
Year three	335,124	461,613
Year four	460,353	332,482
Year five	326,451	259,723
More than five years	1,062,113	865,567
Revolving	36,481	36,948
Revolving-Term	0	0
Total	2,680,009	2,659,039
Commercial | Commercial real estate | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Year two	0
Year three	0	7,107
Year four	2,458	2,261
Year five	2,261	6,296
More than five years	21,071	15,824
Revolving	0	0
Revolving-Term	0	0
Total	25,790	31,488
Commercial | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	42,350	437,529
Year two	369,108	126,371
Year three	107,500	134,417
Year four	113,383	86,912
Year five	79,411	41,422
More than five years	162,305	136,470
Revolving	584,449	550,402
Revolving-Term	0	0
Total	1,458,506	1,513,523
Commercial | Commercial and industrial | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	42,350	437,529
Year two	369,108	126,371
Year three	107,500	123,944
Year four	104,858	86,852
Year five	79,353	38,540
More than five years	162,248	136,427
Revolving	582,519	548,622
Revolving-Term	0	0
Total	1,447,936	1,498,285
Commercial | Commercial and industrial | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Year two	0	0
Year three	0	10,473
Year four	8,525	60
Year five	58	2,882
More than five years	57	43
Revolving	1,930	1,780
Revolving-Term	0	0
Total	10,570	15,239
Commercial | Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	24,551	142,321
Year two	161,638	110,562
Year three	72,342	113,532
Year four	77,597	16,838
Year five	4,988	989
More than five years	11,095	10,477
Revolving	31,026	30,036
Revolving-Term	0	0
Total	383,237	424,755
Commercial | Commercial construction | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	24,551	142,321
Year two	161,638	110,562
Year three	72,342	111,445
Year four	77,117	16,838
Year five	4,988	989
More than five years	10,711	10,093
Revolving	31,026	30,036
Revolving-Term	0	0
Total	382,373	422,284
Commercial | Commercial construction | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Year two	0	0
Year three	0	2,087
Year four	480	0
Year five	0	0
More than five years	384	384
Revolving	0	0
Revolving-Term	0	0
Total	864	2,471
Commercial | Business banking
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	66,205	257,409
Year two	255,151	108,048
Year three	105,295	144,976
Year four	135,148	115,228
Year five	106,319	81,889
More than five years	361,297	318,735
Revolving	110,593	108,230
Revolving-Term	1,228	1,179
Total	1,141,236	1,135,693
Commercial | Business banking | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	66,205	257,368
Year two	255,149	107,984
Year three	105,295	144,689
Year four	134,873	113,820
Year five	104,917	81,195
More than five years	355,063	311,673
Revolving	110,565	108,202
Revolving-Term	1,172	1,122
Total	1,133,239	1,126,052
Commercial | Business banking | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	41
Year two	2	64
Year three	0	287
Year four	275	1,408
Year five	1,402	694
More than five years	6,234	7,062
Revolving	28	28
Revolving-Term	56	57
Total	7,997	9,641
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,632,048	1,593,406
Consumer | Business banking
Financing Receivable, Credit Quality Indicator [Line Items]
Total		357,900
Consumer | Consumer real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	56,284	137,465
Year two	141,486	100,995
Year three	97,071	92,165
Year four	85,206	50,156
Year five	36,916	40,384
More than five years	235,623	238,462
Revolving	483,849	443,406
Revolving-Term	26,422	24,552
Total	1,162,857	1,127,585
Consumer | Consumer real estate | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	56,284	137,465
Year two	141,486	100,253
Year three	96,167	91,689
Year four	84,952	49,853
Year five	36,674	39,657
More than five years	230,971	234,297
Revolving	483,658	443,238
Revolving-Term	25,487	23,839
Total	1,155,679	1,120,291
Consumer | Consumer real estate | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Year two	0	742
Year three	904	476
Year four	254	303
Year five	242	727
More than five years	4,652	4,165
Revolving	191	168
Revolving-Term	935	713
Total	7,178	7,294
Consumer | Other consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	6,035	20,059
Year two	15,522	9,448
Year three	8,176	7,261
Year four	5,948	3,093
Year five	2,452	1,021
More than five years	1,351	6,444
Revolving	71,494	57,903
Revolving-Term	1,298	2,677
Total	112,276	107,906
Consumer | Other consumer | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	6,035	20,059
Year two	15,522	9,290
Year three	8,051	7,261
Year four	5,948	3,093
Year five	2,452	1,021
More than five years	1,351	6,444
Revolving	71,494	57,903
Revolving-Term	1,298	2,677
Total	112,151	107,748
Consumer | Other consumer | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Year two	0	158
Year three	125	0
Year four	0	0
Year five	0	0
More than five years	0	0
Revolving	0	0
Revolving-Term	0	0
Total	$ 125	$ 158