Investment Securities - Additional Information (Details)	3 Months Ended
	Mar. 31, 2023 USD ($) Security	Dec. 31, 2022 USD ($) Securities Security
Schedule Of Available For Sale Securities [Line Items]
Equity securities, at fair value	$ 362,000	$ 311,000
Tax rate used to calculate tax-equivalent yields (in hundredths)	21.00%
Percentage investment book value exceeds stockholders' equity (in hundredths)	10.00%
Debt securities, available-for-sale, restricted	$ 709,000,000	770,000,000
Available-for-sale, 12 months or longer, Fair Value	1,099,203,000	677,083,000
12 months or longer, unrealized losses	$ 192,066,000	$ 143,282,000
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies
Schedule Of Available For Sale Securities [Line Items]
Number of securities in unrealized loss positions | Security	45	16
Available-for-sale, 12 months or longer, Fair Value	$ 220,714,000	$ 163,520,000
12 months or longer, unrealized losses	$ 29,669,000	$ 28,914,000
Held-to-maturity, securities in unrealized loss positions, qualitative disclosure, number of positions | Securities		0
Obligations of States and Political Subdivisions
Schedule Of Available For Sale Securities [Line Items]
Number of securities in unrealized loss positions | Security	202	36
Available-for-sale, 12 months or longer, Fair Value	$ 212,715,000	$ 45,419,000
12 months or longer, unrealized losses	$ 53,765,000	$ 16,624,000
Mortgage-backed Securities: GSE Residential
Schedule Of Available For Sale Securities [Line Items]
Number of securities in unrealized loss positions | Security	219	91
Available-for-sale, 12 months or longer, Fair Value	$ 610,896,000	$ 461,446,000
12 months or longer, unrealized losses	$ 105,178,000	$ 96,900,000
Other Securities
Schedule Of Available For Sale Securities [Line Items]
Number of securities in unrealized loss positions | Security	40	5
Available-for-sale, 12 months or longer, Fair Value	$ 54,878,000	$ 6,698,000
12 months or longer, unrealized losses	$ 3,454,000	$ 844,000