Loans - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 7,073,387,000		$ 7,073,387,000		$ 6,857,194,000
Syndication facilities included in loans	312,000,000		312,000,000		367,000,000
Collateral of cash, cash equivalents or other financial instruments	6,600,000		6,600,000		6,300,000
Interest income on nonaccrual loans	0	$ 0	0	$ 0
Interest receivable	33,000,000		33,000,000		27,700,000
Reversal of interest receivable	100,000		500,000
International
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	103,300,000		103,300,000		99,200,000
Consumer loans and overdrafts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	438,997,000		438,997,000		604,460,000
Reversal of interest receivable		300,000
Real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	5,168,278,000		5,168,278,000		4,858,208,000
Real estate loans | Indirect Consumer Loans Purchased
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments to acquire loans held-for-investment		91,000,000		345,000,000
Real estate loans | Single-family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,371,194,000		1,371,194,000		1,102,845,000
Payments to acquire loans held-for-investment	10,300,000	$ 110,300,000	17,500,000	132,100,000
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,452,759,000		1,452,759,000		1,381,234,000
Commercial loans | Indirect Consumer Loans Purchased
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments to acquire loans held-for-investment	0		0
Indirect Consumer Loans Purchased | Consumer loans and overdrafts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	254,700,000		254,700,000		433,300,000
Under Non-Accrual Status
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reversal of interest receivable				600,000
Under Non-Accrual Status | Consumer loans and overdrafts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reversal of interest receivable				500,000
Under Non-Accrual Status | Real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reversal of interest receivable				$ 100,000
Pledged as Collateral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 2,500,000,000		$ 2,500,000,000		$ 1,200,000,000