Investment Securities - Additional Information (Details)	3 Months Ended
	Mar. 31, 2024 USD ($) Position Security	Dec. 31, 2023 USD ($) Position Security
Schedule Of Available For Sale Securities [Line Items]
Equity securities, at fair value	$ 4,298,000	$ 4,074,000
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	$ 820,000,000	831,000,000
Available-for-sale, 12 months or longer, Fair Value	1,057,538,000	1,075,835,000
12 months or longer, unrealized losses	$ 203,245,000	$ 192,616,000
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	625	36
Available-for-sale, 12 months or longer, Fair Value	$ 206,025,000	$ 210,069,000
12 months or longer, unrealized losses	$ 27,220,000	$ 26,215,000
Held-to-maturity, securities in unrealized loss positions, qualitative disclosure, number of positions | Position	0	0
Obligations of States and Political Subdivisions
Schedule Of Available For Sale Securities [Line Items]
Number of securities in unrealized loss positions | Security	255	237
Available-for-sale, 12 months or longer, Fair Value	$ 248,168,000	$ 241,630,000
12 months or longer, unrealized losses	$ 52,540,000	$ 49,038,000
Mortgage-backed Securities: GSE Residential
Schedule Of Available For Sale Securities [Line Items]
Number of securities in unrealized loss positions | Security	263	263
Available-for-sale, 12 months or longer, Fair Value	$ 545,899,000	$ 566,197,000
12 months or longer, unrealized losses	$ 119,639,000	$ 113,007,000
Other Securities
Schedule Of Available For Sale Securities [Line Items]
Number of securities in unrealized loss positions | Security	42	43
Available-for-sale, 12 months or longer, Fair Value	$ 57,446,000	$ 57,939,000
12 months or longer, unrealized losses	$ 3,846,000	$ 4,356,000