Fair Value Measurement of Assets and Liabilities - Recurring and Non-Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Investment securities:
Equity securities	$ 74,425	$ 71,513
Available for sale debt securities:
Available for sale debt securities	3,658,704	3,369,724
Loans held for sale	8,427	16,931
Non-recurring fair value measurements:
Unpaid principal balances of loans held for sale	8,300	16,800
U.S. Treasury securities
Available for sale debt securities:
Available for sale debt securities	296,253	291,549
U.S. government agency securities
Available for sale debt securities:
Available for sale debt securities	22,400	22,543
Obligations of states and political subdivisions
Available for sale debt securities:
Available for sale debt securities	187,381	192,509
Residential mortgage-backed securities
Available for sale debt securities:
Available for sale debt securities	2,967,535	2,681,076
Corporate and other debt securities
Available for sale debt securities:
Available for sale debt securities	185,135	182,047
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements
Investment securities:
Equity securities	23,545	23,642
Available for sale debt securities:
Available for sale debt securities	296,253	291,549
Loans held for sale	0	0
Other assets	0	0
Total assets	319,798	315,191
Liabilities
Other liabilities	0	0
Total liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | U.S. Treasury securities
Available for sale debt securities:
Available for sale debt securities	296,253	291,549
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | U.S. government agency securities
Available for sale debt securities:
Available for sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | Obligations of states and political subdivisions
Available for sale debt securities:
Available for sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | Residential mortgage-backed securities
Available for sale debt securities:
Available for sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | Corporate and other debt securities
Available for sale debt securities:
Available for sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-recurring fair value measurements
Non-recurring fair value measurements:
Non-performing loan held for sale		0
Collateral dependent loans	0	0
Foreclosed assets	0	0
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-recurring fair value measurements | Non-performing loan held for sale
Available for sale debt securities:
Loans held for sale	0
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements
Investment securities:
Equity securities	0	0
Available for sale debt securities:
Available for sale debt securities	3,362,451	3,078,175
Loans held for sale	8,427	16,931
Other assets	326,722	444,263
Total assets	3,697,600	3,539,369
Liabilities
Other liabilities	332,888	454,200
Total liabilities	332,888	454,200
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | U.S. Treasury securities
Available for sale debt securities:
Available for sale debt securities	0	0
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | U.S. government agency securities
Available for sale debt securities:
Available for sale debt securities	22,400	22,543
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Obligations of states and political subdivisions
Available for sale debt securities:
Available for sale debt securities	187,381	192,509
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Residential mortgage-backed securities
Available for sale debt securities:
Available for sale debt securities	2,967,535	2,681,076
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Corporate and other debt securities
Available for sale debt securities:
Available for sale debt securities	185,135	182,047
Significant Other Observable Inputs (Level 2) | Non-recurring fair value measurements
Non-recurring fair value measurements:
Non-performing loan held for sale		8,750
Collateral dependent loans	0	0
Foreclosed assets	0	0
Total	18,950	8,750
Significant Other Observable Inputs (Level 2) | Non-recurring fair value measurements | Non-performing loan held for sale
Available for sale debt securities:
Loans held for sale	18,950
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements
Investment securities:
Equity securities	0	0
Available for sale debt securities:
Available for sale debt securities	0	0
Loans held for sale	0	0
Other assets	0	0
Total assets	0	0
Liabilities
Other liabilities	0	0
Total liabilities	0	0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | U.S. Treasury securities
Available for sale debt securities:
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | U.S. government agency securities
Available for sale debt securities:
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | Obligations of states and political subdivisions
Available for sale debt securities:
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | Residential mortgage-backed securities
Available for sale debt securities:
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | Corporate and other debt securities
Available for sale debt securities:
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) | Non-recurring fair value measurements
Non-recurring fair value measurements:
Non-performing loan held for sale		0
Collateral dependent loans	81,473	139,424
Foreclosed assets	9,768	13,852
Total	91,241	153,276
Significant Unobservable Inputs (Level 3) | Non-recurring fair value measurements | Non-performing loan held for sale
Available for sale debt securities:
Loans held for sale	0
Fair Value | Recurring fair value measurements
Available for sale debt securities:
Available for sale debt securities	3,658,704	3,369,724
Loans held for sale	8,427	16,931
Other assets	326,722	444,263
Total assets	4,028,268	3,865,560
Liabilities
Other liabilities	332,888	454,200
Total liabilities	332,888	454,200
Fair Value | Recurring fair value measurements | U.S. Treasury securities
Available for sale debt securities:
Available for sale debt securities	296,253	291,549
Fair Value | Recurring fair value measurements | U.S. government agency securities
Available for sale debt securities:
Available for sale debt securities	22,400	22,543
Fair Value | Recurring fair value measurements | Obligations of states and political subdivisions
Available for sale debt securities:
Available for sale debt securities	187,381	192,509
Fair Value | Recurring fair value measurements | Residential mortgage-backed securities
Available for sale debt securities:
Available for sale debt securities	2,967,535	2,681,076
Fair Value | Recurring fair value measurements | Corporate and other debt securities
Available for sale debt securities:
Available for sale debt securities	185,135	182,047
Fair Value | Non-recurring fair value measurements
Non-recurring fair value measurements:
Non-performing loan held for sale		8,750
Collateral dependent loans	81,473	139,424
Foreclosed assets	9,768	13,852
Total	110,191	162,026
Fair Value | Non-recurring fair value measurements | Non-performing loan held for sale
Available for sale debt securities:
Loans held for sale	18,950
Fair Value | Fair Value, Inputs, Level 1, Level 2, and Level 3 | Recurring fair value measurements
Investment securities:
Equity securities	23,545	23,642
Fair Value | Significant Unobservable Inputs (Level 3)
Investment securities:
Equity securities	40,010	36,871
Fair Value | NAV | Recurring fair value measurements
Investment securities:
Equity securities	$ 10,870	$ 11,000