Debt Securities Available for Sale - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($) security	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) security	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Mortgage-backed securities and collateralized mortgage obligations	$ 1,399,397,000		$ 1,399,397,000
Mortgage-backed securities and collateralized mortgage obligations	1,223,652,000		1,223,652,000
Proceeds from sales of debt securities available for sale	0	$ 22,500,000	126,772,000	$ 27,249,000
Gross gains on sale of available-for-sale securities		2,000,000	210,000	2,000,000
Gross losses on sale of available-for-sale securities		0	0	281,000
Proceeds from calls of debt securities available for sale	0	9,000,000	0	14,000,000
Proceeds from maturities of debt securities, available-for-sale	915,000	0	915,000	210,000
Calls of debt securities, available-for-sale, realized gain		0		0
Calls of debt securities, available-for-sale, unrealized loss		$ 0		$ 0
Debt securities, available-for-sale, restricted	$ 636,000,000		$ 636,000,000		$ 587,700,000
Number of securities in unrealized loss position | security	439		439		219
Accrued interest receivable on debt securities available for sale	$ 3,100,000		$ 3,100,000
Subsidiaries
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, restricted	$ 30,100,000		$ 30,100,000		$ 44,100,000