Loans Receivable, Net - Aging Analysis (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	$ 16,135,046	$ 15,246,812
Accruing loans 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	10,961	16,331
Accruing loans 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	4,292	4,636
Accruing loans 90 days or more past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	3,855	1,559
Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	57,488	53,677
Non-accrual loans with no ACL	38,348	31,036
Non-accrual loans with ACL	32	115
Current loans receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	16,077,558	15,193,135
Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	1,653,777	1,446,008
Residential real estate | Accruing loans 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	37	2,796
Residential real estate | Accruing loans 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	735	142
Residential real estate | Accruing loans 90 days or more past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	107	215
Residential real estate | Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	3,551	5,389
Non-accrual loans with no ACL	2,672	2,236
Non-accrual loans with ACL	0	0
Residential real estate | Current loans receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	1,650,226	1,440,619
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	10,292,446	9,797,047
Commercial real estate | Accruing loans 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	2,950	5,462
Commercial real estate | Accruing loans 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	598	2,865
Commercial real estate | Accruing loans 90 days or more past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	1,537	472
Commercial real estate | Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	36,599	31,742
Non-accrual loans with no ACL	31,514	22,943
Non-accrual loans with ACL	0	0
Commercial real estate | Current loans receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	10,255,847	9,765,305
Other commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	2,916,785	2,799,668
Other commercial | Accruing loans 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	3,012	4,192
Other commercial | Accruing loans 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	782	297
Other commercial | Accruing loans 90 days or more past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	1,818	542
Other commercial | Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	7,213	8,877
Non-accrual loans with no ACL	1,586	3,790
Non-accrual loans with ACL	15	56
Other commercial | Current loans receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	2,909,572	2,790,791
Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	869,963	822,232
Home equity | Accruing loans 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	2,254	754
Home equity | Accruing loans 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	1,452	529
Home equity | Accruing loans 90 days or more past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	210	138
Home equity | Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	5,469	2,655
Non-accrual loans with no ACL	1,553	1,234
Non-accrual loans with ACL	0	0
Home equity | Current loans receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	864,494	819,577
Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	402,075	381,857
Other consumer | Accruing loans 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	2,708	3,127
Other consumer | Accruing loans 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	725	803
Other consumer | Accruing loans 90 days or more past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	183	192
Other consumer | Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	4,656	5,014
Non-accrual loans with no ACL	1,023	833
Non-accrual loans with ACL	17	59
Other consumer | Current loans receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans receivable	$ 397,419	$ 376,843