Investment Securities - Narrative (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) investment_security	Dec. 31, 2021 USD ($) investment_security	Dec. 31, 2020 USD ($)
Investment Holdings [Line Items]
Transfers of investment securities from available-for-sale to held-to-maturity	$ 1,019,472,000	$ 319,924,000	$ 0
Unrealized loss on securities transferred from available-for-sale to held-to-maturity	291,051,000	1,649,000
Accumulated other comprehensive loss, net of tax	(265,247,000)	(7,862,000)
Investments held-to-maturity, allowance for credit losses	43,000	22,000	$ 0
Allowance for credit losses on debt securities, available-for-sale	0	0
Available-for-sale securities, provision for credit losses	$ 0	$ 0
Available-for-sale and held-to-maturity securities in nonaccrual status | investment_security	0	0
Available-for-sale and held-to-maturity securities purchased with deterioration in credit quality | investment_security	0	0
Available-for-sale and held-to-maturity collateral dependent | investment_security	0	0
FHLB stock	$ 27,700,000	$ 17,300,000
FRB stock	74,800,000	74,500,000
Other stock	17,400,000	25,700,000
Impairment loss on investments in FHLB, FRB and other stock	0
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent
Investment Holdings [Line Items]
Accumulated other comprehensive income (loss) before tax	(303,700,000)	(4,700,000)
Accumulated other comprehensive loss, net of tax	(217,400,000)	(3,300,000)
Asset Pledged as Collateral
Investment Holdings [Line Items]
Investments	195,600,000	130,700,000
Municipal bonds
Investment Holdings [Line Items]
Securities transferred from available-for-sale to held-to-maturity	831,400,000
Transfers of investment securities from available-for-sale to held-to-maturity	780,700,000
Debt securities, held-to-maturity, transfer, unrealized loss	(50,800,000)
Unrealized loss on securities transferred from available-for-sale to held-to-maturity	257,430,000	1,649,000
Accumulated other comprehensive income (loss) before tax	(66,900,000)
Accumulated other comprehensive loss, net of tax	(47,900,000)
Investments held-to-maturity, allowance for credit losses	43,000	22,000
Mortgage-backed securities
Investment Holdings [Line Items]
Securities transferred from available-for-sale to held-to-maturity	255,000,000
Transfers of investment securities from available-for-sale to held-to-maturity	238,800,000
Debt securities, held-to-maturity, transfer, unrealized loss	(16,200,000)
Unrealized loss on securities transferred from available-for-sale to held-to-maturity	33,621,000	0
Investments held-to-maturity, allowance for credit losses	$ 0	$ 0