Financial Instruments Subject to Off-Balance Sheet Credit Risk - Offsetting Assets and Liabilities (Details) - USD ($) $ in Thousands		Dec. 31, 2023	Dec. 31, 2022
Resale agreements
Gross Assets		$ 8,844,000	$ 12,159,000
Gross Amounts Offset in the Consolidated Balance Sheets		0	0
Net Amounts Presented in the Consolidated Balance Sheets	[1]	8,844,000	12,159,000
Counterparty Offsetting		0	0
Collateral		(8,844,000)	(12,159,000)
Net Amount		0	0
Securities borrowed
Gross Assets		1,563,000	705,000
Gross Amounts Offset in the Consolidated Balance Sheets		0	0
Net Amounts Presented in the Consolidated Balance Sheets		1,563,000	705,000
Counterparty Offsetting		(1,307,000)	(331,000)
Collateral		(253,000)	(366,000)
Net Amount		3,000	8,000
Interest rate swaps
Total Gross Assets		10,407,000	12,864,000
Gross Amounts Offset in the Consolidated Balance Sheets		0	0
Net Amounts Presented in the Consolidated Balance Sheets		10,407,000	12,864,000
Counterparty Offsetting		(1,307,000)	(331,000)
Collateral		(9,097,000)	(12,525,000)
Net Amount		3,000	8,000
Repurchase agreements
Gross Liabilities		4,903,000	4,402,000
Gross Amounts Offset in the Consolidated Balance Sheets		0	0
Net Amounts Presented in the Consolidated Balance Sheets		4,903,000	4,402,000
Counterparty Offsetting		0	0
Collateral		(4,903,000)	(4,402,000)
Net Amount		0	0
Securities loaned
Gross Liabilities		5,397,000	4,200,000
Gross Amounts Offset in the Consolidated Balance Sheets		0	0
Net Amounts Presented in the Consolidated Balance Sheets		5,397,000	4,200,000
Counterparty Offsetting		(1,307,000)	(331,000)
Collateral		(3,619,000)	(3,313,000)
Net Amount		471,000	556,000
Secured short-term borrowings
Total	[1]	6,553,000	4,650,000
Interest rate swaps
Total Gross Liabilities		11,950,000	8,602,000
Gross Amounts Offset in the Consolidated Balance Sheets		0	0
Net Amounts Presented in the Consolidated Balance Sheets		11,950,000	8,602,000
Counterparty Offsetting		(1,307,000)	(331,000)
Collateral		(10,172,000)	(7,715,000)
Net Amount		471,000	556,000
Fair value of client securities available to be pledged		86,911,000	86,775,000
Available for sale securities	[1]	107,646,000	147,871,000
Interest rate swaps
Interest rate swaps
Gross Assets		0
Gross Amounts Offset in the Consolidated Balance Sheets		0
Net Amounts Presented in the Consolidated Balance Sheets		0
Counterparty Offsetting		0
Collateral		0
Net Amount		0
Interest rate swaps
Gross Liabilities		0
Gross Amounts Offset in the Consolidated Balance Sheets		0
Net Amounts Presented in the Consolidated Balance Sheets		0
Counterparty Offsetting		0
Collateral		0
Net Amount		0
Derivative asset less than stated amount		500
Derivative liability less than stated amount		500
Asset Pledged as Collateral
Interest rate swaps
Available for sale securities	[1]	1,733,000	41,000
Secured short-term borrowings
Secured short-term borrowings
Gross Liabilities		1,650,000
Gross Amounts Offset in the Consolidated Balance Sheets		0
Total		1,650,000
Counterparty Offsetting		0
Collateral		(1,650,000)
Net Amount		0
Securities Sold under Agreements to Repurchase
Interest rate swaps
Fair value of collateral pledged in connection with repurchase agreements		5,300,000	4,600,000
Interest rate swaps | Asset Pledged as Collateral
Interest rate swaps
Available for sale securities		195,000
Resale And Repurchase Agreements
Interest rate swaps
Fair value of client securities available to be pledged		$ 9,000,000	$ 12,300,000

[1] Certain prior year amounts have been reclassified to conform to the current year presentation. See Note 1 for additional information.