Securities Available for Sale and Held to Maturity - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2013
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Reclassification of Securities available for sale to securities held to maturity				$ 1,099,000,000.000
Net unrealized holding loss on AFS Securities at date of transfer				46,600,000
Net unrealized holding losses on AFS Securities, net of tax at date of transfer				$ 28,800,000
Net unamortized, unrealized loss on transfer of securities	$ 5,800,000		$ 6,300,000
Net unamortized, unrealized loss on transfer of securities, net of tax	4,300,000		4,700,000
Credit loss recognized	0		0
Potential credit loss exposure	7,300,000		7,300,000
Securities held to maturity	607,598,000		342,537,000
Realized gains or losses on security	0	$ 0
Pledged to collateralize public deposits and securities sold under repurchase agreements and for other purposes as permitted by law	2,674,000,000		2,831,000,000
Pledged securities providing additional contingency funding	0		0
30 Days or More Past Due [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Securities held to maturity	0		0
Securities Available for Sale [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Accrued interest receivable	5,000,000.0		5,100,000
Securities Held to Maturity [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Accrued interest receivable	1,100,000		670,000
Reserve for credit loss	0		0
Held-to-maturity nonnaccrual	$ 0		$ 0