Debt Securities Available for Sale - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($) security	Jun. 30, 2021 USD ($) security	Jun. 30, 2022 USD ($) security	Jun. 30, 2021 USD ($) security	Dec. 31, 2021 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Mortgage-backed securities and collateralized mortgage obligations	$ 1,452,210,000		$ 1,452,210,000
Mortgage-backed securities and collateralized mortgage obligations	1,335,347,000		1,335,347,000
Proceeds from sales of debt securities available for sale	126,800,000	$ 4,700,000	126,772,000	$ 4,719,000
Gross gains on sale of available-for-sale securities	210,000		210,000
Gross losses on sale of available-for-sale securities	0	$ 281,000	0
Debt securities, available-for-sale, number of called debt securities | security		1		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
Sale and maturity of debt securities, available-for-sale	0	$ 0	0	$ 210,000
Debt securities, available-for-sale, restricted	$ 637,500,000		$ 637,500,000		$ 587,700,000
Number of securities in unrealized loss position | security	405		405		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	$ 34,400,000		$ 34,400,000		$ 44,100,000