Investment Securities - Amortized Cost of Held to Maturity Debt Securities by External Credit Rating (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	$ 3,532,220	$ 3,740,413
U.S. Treasury securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	25,480	26,232
U.S. government agency securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	301,315	305,996
Obligations of states and state agencies
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	68,025	88,556
Municipal bonds
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	304,464	316,914
Obligations of states and political subdivisions
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	372,489	405,470
Residential mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	2,710,642	2,885,303
Trust preferred securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	36,081	37,062
Corporate and other debt securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	86,213	80,350
AAA/AA/A Rated
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	3,368,128	3,567,474
AAA/AA/A Rated | U.S. Treasury securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	25,480	26,232
AAA/AA/A Rated | U.S. government agency securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	301,315	305,996
AAA/AA/A Rated | Obligations of states and state agencies
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	52,770	66,502
AAA/AA/A Rated | Municipal bonds
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	277,921	283,441
AAA/AA/A Rated | Obligations of states and political subdivisions
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	330,691	349,943
AAA/AA/A Rated | Residential mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	2,710,642	2,885,303
AAA/AA/A Rated | Trust preferred securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities		0
AAA/AA/A Rated | Corporate and other debt securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
BBB rated
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	6,000	6,000
BBB rated | U.S. Treasury securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
BBB rated | U.S. government agency securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
BBB rated | Obligations of states and state agencies
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
BBB rated | Municipal bonds
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
BBB rated | Obligations of states and political subdivisions
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
BBB rated | Residential mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
BBB rated | Trust preferred securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
BBB rated | Corporate and other debt securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	6,000	6,000
Non-investment grade rated
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	5,330
Non-investment grade rated | U.S. Treasury securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
Non-investment grade rated | U.S. government agency securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
Non-investment grade rated | Obligations of states and state agencies
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	5,330
Non-investment grade rated | Municipal bonds
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
Non-investment grade rated | Obligations of states and political subdivisions
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	5,330
Non-investment grade rated | Residential mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
Non-investment grade rated | Trust preferred securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
Non-investment grade rated | Corporate and other debt securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
Non-rated
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	158,092	161,609
Non-rated | U.S. Treasury securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
Non-rated | U.S. government agency securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
Non-rated | Obligations of states and state agencies
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	15,255	16,724
Non-rated | Municipal bonds
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	26,543	33,473
Non-rated | Obligations of states and political subdivisions
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	41,798	50,197
Non-rated | Residential mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	0	0
Non-rated | Trust preferred securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	36,081	37,062
Non-rated | Corporate and other debt securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized cost of held to maturity debt securities	$ 80,213	$ 74,350