Loans and Allowance for Credit Losses - Narrative (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023 USD ($) loan	Jun. 30, 2022 USD ($) loan	Jun. 30, 2023 USD ($) loan	Jun. 30, 2022 USD ($) loan	Dec. 31, 2022 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 16,833,653,000		$ 16,833,653,000		$ 16,142,124,000
Deferred origination fees, net			13,600,000		26,400,000
Financing receivable, accrued interest excluded from amortized costs	66,200,000		66,200,000		65,400,000
Nonaccrual loans with no allowance for credit loss	$ 13,000,000		13,000,000		16,900,000
Number of loan modifications | loan		1		1
Number of investments with prior modification		$ 13,000		$ 13,000
Combination: Interest Rate Modification and Term Extension			$ 655,000
Number of loan modifications with payment default | loan	0		0
Foreclosed assets and other real estate owned	$ 3,909,000		$ 3,909,000		2,887,000
Financing receivable, collateral dependent, amount	99,721,000		99,721,000		70,926,000
Unfunded commitments	(5,000,000)	3,453,000	$ (5,000,000)	3,453,000
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, term of loan			1 year
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, term of loan			3 years
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in process of foreclosure, amount	1,300,000		$ 1,300,000		3,000,000
OREO Received in Full or Partial Satisfaction of Loans | Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Foreclosed assets and other real estate owned	423,000		423,000		853,000
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	13,110,081,000		13,110,081,000		12,581,262,000
Real Estate | OREO Received in Full or Partial Satisfaction of Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of investments with prior modification		0		0
Unfunded Loan Commitment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unfunded commitments, allowance for credit loss	36,900,000		36,900,000		41,900,000
Reserve for unfunded commitments, expensed (released)	(5,000,000)	$ 3,500,000	(5,000,000)	$ 3,500,000
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 2,849,871,000		$ 2,849,871,000		2,837,913,000
Number of loan modifications | loan	1		1
Combination: Interest Rate Modification and Term Extension			$ 655,000
Single family residential | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 2,633,365,000		2,633,365,000		2,546,115,000
Financing receivable, collateral dependent, amount	1,446,000		1,446,000		0
Commercial real estate | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans with subsequent default | loan				0
Paycheck Protection Program Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 6,800,000		$ 6,800,000		$ 8,900,000