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Loans Receivable - Originated and Acquired Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	$ 13,229,227		$ 13,007,316
Allowance for credit losses	(149,321)	$ (150,045)	(150,212)	$ (129,159)	$ (122,809)	$ (116,819)
Total loans receivable, net	13,079,906		12,857,104
Unearned income, unamortized premiums and discounts and deferred fees and costs	22,000		8,000
Personal Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	7,342,123		7,172,202
Allowance for credit losses	(45,423)	(47,603)	(47,457)	(39,805)	(42,351)	(43,464)
Personal Banking \| Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	3,001,908		3,100,780
Allowance for credit losses	(10,174)	(9,895)	(10,546)	(12,089)	(13,275)	(14,347)
Personal Banking \| Home equity loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	1,497,157		1,507,532
Allowance for credit losses	(6,211)	(6,340)	(6,149)	(4,216)	(4,624)	(4,845)
Personal Banking \| Vehicle loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	2,700,189		2,426,636
Allowance for credit losses	(24,744)	(26,346)	(25,945)	(21,234)	(22,455)	(22,389)
Personal Banking \| Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	142,869		137,254
Allowance for credit losses	(4,294)	(5,022)	(4,817)	(2,266)	(1,997)	(1,883)
Commercial Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	5,887,104		5,835,114
Allowance for credit losses	(103,898)	(102,442)	(102,755)	(89,354)	(80,458)	(73,355)
Commercial Banking \| Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	2,610,861		2,915,696
Allowance for credit losses	(54,091)	(56,604)	(58,234)	(53,624)	(45,583)	(44,328)
Commercial Banking \| Commercial real estate loans - owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	377,376		381,206
Allowance for credit losses	(5,016)	(5,030)	(4,679)	(4,130)	(4,187)	(3,882)
Commercial Banking \| Commercial and industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	2,898,867		2,538,212
Allowance for credit losses	$ (44,791)	$ (40,808)	$ (39,842)	$ (31,600)	$ (30,688)	$ (25,145)