Debt Securities Available for Sale - Narrative (Details)	3 Months Ended
Mar. 31, 2022 USD ($) security	Mar. 31, 2021 USD ($) security	Dec. 31, 2021 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Mortgage-backed securities and collateralized mortgage obligations	$ 1,488,048,000
Mortgage-backed securities and collateralized mortgage obligations	1,414,142,000
Proceeds from sales of debt securities available for sale	0	$ 0
Debt securities, available-for-sale, number of called debt securities \| security		1
Proceeds from calls of debt securities available for sale		$ 5,000,000
Calls of debt securities, available-for-sale, realized gain		0
Calls of debt securities, available-for-sale, unrealized loss		$ 0
Debt securities, available-for-sale, number of matured debt securities \| security		2
Sale and maturity of debt securities, available-for-sale		$ 210,000
Debt securities, available-for-sale, restricted	$ 610,800,000		$ 587,700,000
Number of securities in unrealized loss position \| security	393		219
Accrued interest receivable on debt securities available for sale	$ 3,300,000
Subsidiaries
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, restricted	$ 37,900,000		$ 44,100,000

Calls Of Debt Securities, Available-for-sale, Realized Gain

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Calls Of Debt Securities, Available-for-sale, Unrealized Loss

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Debt Securities, Available-For-Sale, Number Of Called Debt Securities

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Debt Securities, Available-For-Sale, Number Of Matured Debt Securities

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Proceeds From Calls of Debt Securities, Available-for-sale

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), without single maturity date and not allocated over maturity grouping.

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), without single maturity date and not allocated over maturity grouping.

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Amount, after allowance for credit loss, of accrued interest on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of restricted investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of cash inflow from sale, maturity, prepayment and call of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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