Fair Value of Assets and Liabilities - Balances of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets:
Available-for-Sale: Fair Value	$ 2,352,051	$ 2,408,933
Loans Held for Sale	2,182	3,124
Debt Securities Issued by States and Political Subdivisions
Assets:
Available-for-Sale: Fair Value	63,451	63,806
Debt Securities Issued by Government-Sponsored Enterprises
Assets:
Available-for-Sale: Fair Value	1,425	1,476
Debt Securities Issued by Corporations
Assets:
Available-for-Sale: Fair Value	661,146	657,701
Residential - Government Agencies
Assets:
Available-for-Sale: Fair Value	602,276	629,327
Residential - U.S. Government-Sponsored Enterprises
Assets:
Available-for-Sale: Fair Value	684,573	709,127
Mortgage-Backed Securities
Assets:
Available-for-Sale: Fair Value	1,419,717	1,473,377
Commercial - Government Agencies or Sponsored Agencies
Assets:
Available-for-Sale: Fair Value	132,868	134,923
Fair Value, Measurements, Recurring
Assets:
Available-for-Sale: Fair Value	2,352,051	2,408,933
Loans Held for Sale	2,182	3,124
Mortgage Servicing Rights	674	678
Other Assets	15,362	13,448
Derivatives	153,160	95,069
Total Assets Measured at Fair Value on a Recurring Basis	2,523,429	2,521,252
Liabilities:
Derivatives	$ 162,366	$ 143,857
Derivative Liability Statement Of Financial Position [ExtensibleEnumeration]	Other Liabilities	Other Liabilities
Total Liabilities Measured at Fair Value on a Recurring Basis	$ 162,366	$ 143,857
Fair Value, Measurements, Recurring | Debt Securities Issued by the U.S. Treasury and Government Agencies
Assets:
Available-for-Sale: Fair Value	206,312	212,573
Fair Value, Measurements, Recurring | Debt Securities Issued by States and Political Subdivisions
Assets:
Available-for-Sale: Fair Value	63,451	63,806
Fair Value, Measurements, Recurring | Debt Securities Issued by Government-Sponsored Enterprises
Assets:
Available-for-Sale: Fair Value	1,425	1,476
Fair Value, Measurements, Recurring | Debt Securities Issued by Corporations
Assets:
Available-for-Sale: Fair Value	661,146	657,701
Fair Value, Measurements, Recurring | Residential - Government Agencies
Assets:
Available-for-Sale: Fair Value	602,276	629,327
Fair Value, Measurements, Recurring | Residential - U.S. Government-Sponsored Enterprises
Assets:
Available-for-Sale: Fair Value	684,573	709,127
Fair Value, Measurements, Recurring | Commercial - Government Agencies
Assets:
Available-for-Sale: Fair Value	132,868
Fair Value, Measurements, Recurring | Mortgage-Backed Securities
Assets:
Available-for-Sale: Fair Value	1,419,717	1,473,377
Fair Value, Measurements, Recurring | Commercial - Government Agencies or Sponsored Agencies
Assets:
Available-for-Sale: Fair Value		134,923
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)
Assets:
Available-for-Sale: Fair Value	145,889	146,214
Loans Held for Sale	0	0
Mortgage Servicing Rights	0	0
Other Assets	15,362	13,448
Derivatives	0	0
Total Assets Measured at Fair Value on a Recurring Basis	161,251	159,662
Liabilities:
Derivatives	$ 0	$ 0
Derivative Liability Statement Of Financial Position [ExtensibleEnumeration]	Other Liabilities	Other Liabilities
Total Liabilities Measured at Fair Value on a Recurring Basis	$ 0	$ 0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Debt Securities Issued by the U.S. Treasury and Government Agencies
Assets:
Available-for-Sale: Fair Value	145,889	146,214
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Debt Securities Issued by States and Political Subdivisions
Assets:
Available-for-Sale: Fair Value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Debt Securities Issued by Government-Sponsored Enterprises
Assets:
Available-for-Sale: Fair Value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Debt Securities Issued by Corporations
Assets:
Available-for-Sale: Fair Value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Residential - Government Agencies
Assets:
Available-for-Sale: Fair Value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Residential - U.S. Government-Sponsored Enterprises
Assets:
Available-for-Sale: Fair Value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Commercial - Government Agencies
Assets:
Available-for-Sale: Fair Value	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Mortgage-Backed Securities
Assets:
Available-for-Sale: Fair Value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Commercial - Government Agencies or Sponsored Agencies
Assets:
Available-for-Sale: Fair Value		0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Available-for-Sale: Fair Value	2,206,162	2,262,719
Loans Held for Sale	2,182	3,124
Mortgage Servicing Rights	0	0
Other Assets	0	0
Derivatives	153,043	94,921
Total Assets Measured at Fair Value on a Recurring Basis	2,361,387	2,360,764
Liabilities:
Derivatives	$ 162,364	$ 143,857
Derivative Liability Statement Of Financial Position [ExtensibleEnumeration]	Other Liabilities	Other Liabilities
Total Liabilities Measured at Fair Value on a Recurring Basis	$ 162,364	$ 143,857
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Debt Securities Issued by the U.S. Treasury and Government Agencies
Assets:
Available-for-Sale: Fair Value	60,423	66,359
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Debt Securities Issued by States and Political Subdivisions
Assets:
Available-for-Sale: Fair Value	63,451	63,806
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Debt Securities Issued by Government-Sponsored Enterprises
Assets:
Available-for-Sale: Fair Value	1,425	1,476
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Debt Securities Issued by Corporations
Assets:
Available-for-Sale: Fair Value	661,146	657,701
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Residential - Government Agencies
Assets:
Available-for-Sale: Fair Value	602,276	629,327
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Residential - U.S. Government-Sponsored Enterprises
Assets:
Available-for-Sale: Fair Value	684,573	709,127
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Commercial - Government Agencies
Assets:
Available-for-Sale: Fair Value	132,868
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Mortgage-Backed Securities
Assets:
Available-for-Sale: Fair Value	1,419,717	1,473,377
Fair Value, Measurements, Recurring | Significant Other Unobservable Inputs (Level 3)
Assets:
Available-for-Sale: Fair Value	0	0
Loans Held for Sale	0	0
Mortgage Servicing Rights	674	678
Other Assets	0	0
Derivatives	117	148
Total Assets Measured at Fair Value on a Recurring Basis	791	826
Liabilities:
Derivatives	$ 2	$ 0
Derivative Liability Statement Of Financial Position [ExtensibleEnumeration]	Other Liabilities	Other Liabilities
Total Liabilities Measured at Fair Value on a Recurring Basis	$ 2	$ 0
Fair Value, Measurements, Recurring | Significant Other Unobservable Inputs (Level 3) | Debt Securities Issued by the U.S. Treasury and Government Agencies
Assets:
Available-for-Sale: Fair Value	0	0
Fair Value, Measurements, Recurring | Significant Other Unobservable Inputs (Level 3) | Debt Securities Issued by States and Political Subdivisions
Assets:
Available-for-Sale: Fair Value	0	0
Fair Value, Measurements, Recurring | Significant Other Unobservable Inputs (Level 3) | Debt Securities Issued by Government-Sponsored Enterprises
Assets:
Available-for-Sale: Fair Value	0	0
Fair Value, Measurements, Recurring | Significant Other Unobservable Inputs (Level 3) | Debt Securities Issued by Corporations
Assets:
Available-for-Sale: Fair Value	0	0
Fair Value, Measurements, Recurring | Significant Other Unobservable Inputs (Level 3) | Residential - Government Agencies
Assets:
Available-for-Sale: Fair Value	0	0
Fair Value, Measurements, Recurring | Significant Other Unobservable Inputs (Level 3) | Residential - U.S. Government-Sponsored Enterprises
Assets:
Available-for-Sale: Fair Value	0	0
Fair Value, Measurements, Recurring | Significant Other Unobservable Inputs (Level 3) | Commercial - Government Agencies
Assets:
Available-for-Sale: Fair Value	0
Fair Value, Measurements, Recurring | Significant Other Unobservable Inputs (Level 3) | Mortgage-Backed Securities
Assets:
Available-for-Sale: Fair Value	$ 0	0
Fair Value, Measurements, Recurring | Significant Other Unobservable Inputs (Level 3) | Commercial - Government Agencies or Sponsored Agencies
Assets:
Available-for-Sale: Fair Value		$ 0