Investment Securities - Narrative (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2022 USD ($) security	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) security	Dec. 31, 2020 USD ($)
Debt and Equity Securities, FV-NI [Line Items]
Accrued interest receivable	$ 39,069,000		$ 38,528,000
Marketable securities at fair value	3,213,000		3,367,000
Trade date receivable - securities	0		0
Net (loss) gain on change in fair value and sale of equity securities	(154,000)	$ 76,000
Allowance for credit losses for investments	$ 0		$ 0
Number of securities in securities portfolio | security	514		511
Number of securities in securities portfolio, unrealized loss position | security	321		80
Unrealized loss position	$ 1,434,900,000		$ 1,030,914,000
Collateral Pledged
Debt and Equity Securities, FV-NI [Line Items]
Securities pledged	1,253,407,000		1,226,646,000
Debt Securities
Debt and Equity Securities, FV-NI [Line Items]
Accrued interest receivable	5,331,000		5,051,000
Increase (decrease) in debt securities, available for sale	(105,600,000)	(15,400,000)
Unrealized loss position	$ 100,900,000
Unrealized gain position		$ 19,200,000	$ 4,700,000	$ 34,600,000