Investment Securities - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($) security	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) security	Jun. 30, 2022 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) security	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Debt and Equity Securities, FV-NI [Line Items]
Accrued interest receivable	$ 44,973,000		$ 44,973,000			$ 45,684,000
Trade date payable - securities	0		0			0
Allowance for credit losses for investments	$ 0		$ 0			$ 0
Number of securities in securities portfolio | security	505		505			503
Number of securities in securities portfolio, unrealized loss position | security	452		452			454
Unrealized loss position	$ (1,385,173,000)		$ (1,385,173,000)			$ (1,439,911,000)
Marketable securities at fair value	3,031,000		3,031,000			2,990,000
Equity securities without readily determinable market value	23,896,000		23,896,000			22,496,000
Federal Home Loan Bank stock, at cost	40,266,000		40,266,000			58,641,000
Net (loss) gain on change in fair value and sale of equity securities	(28,000)	$ (110,000)	41,000	$ (264,000)
Collateral Pledged
Debt and Equity Securities, FV-NI [Line Items]
Securities pledged	1,138,262,000		1,138,262,000			1,191,021,000
Debt Securities
Debt and Equity Securities, FV-NI [Line Items]
Accrued interest receivable	5,358,000		5,358,000			5,470,000
Increase (decrease) in debt securities, available for sale	(18,748,000)	(66,577,000)	8,375,000	(172,237,000)
Unrealized loss position	$ (226,013,000)	$ (167,510,000)	$ (226,013,000)	$ (167,510,000)	$ (207,265,000)	$ (234,388,000)	$ (100,933,000)
Unrealized gain position								$ 4,727,000