Investment Securities - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Gain (Loss) on Securities [Line Items]
Trading securities	$ 0
Weighted average duration of MBS portfolio	4 years 7 months 6 days
Securities pledged as collateral	$ 2,200,000,000	$ 1,300,000,000
Sale of investment securities available-for-sale	14,051,000	305,812,000	$ 618,194,000
Proceeds from sale of debt securities			39,800,000
Gain on sale of investment securities available for sale	300,000	9,100,000	300,000
Losses from sale of available-for-sale securities	0	0	0
Unamortized premiums	69,400,000	60,400,000
Unaccreted discounts	12,700,000	2,600,000
Owned investment securities	4,100,000,000
Total unrealized losses on securities	79,200,000
Allowance for credit losses	0	0
Held-to-maturity debt securities with an amortized cost basis	90,600,000	111,700,000
Accrued interest	900,000	1,100,000
Debt securities nonaccrual	0	0
Past Due
Gain (Loss) on Securities [Line Items]
Past due held-to-maturity debt securities	$ 0	$ 0
Beneficial
Gain (Loss) on Securities [Line Items]
Securities sold			$ 578,800,000