Investment Securities - Analysis of the Contractual Maturities of Investment Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis Rolling Maturity[Abstract]
Due in One Year or Less	$ 9,012
Due After One Year Through Five Years	443,955
Due After Five Years Through Ten Years	651,597
Due After Ten Years	6,380
Amortized Cost, Total	1,110,944
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-Sale: Amortized Cost	2,993,004	$ 3,172,436
Due in One Year or Less	8,980
Due After One Year Through Five Years	419,503
Due After Five Years Through Ten Years	595,753
Due After Ten Years	5,172
Fair Value, Total	1,029,408
Available-for-Sale: Fair Value	2,666,723	2,844,823
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis, Rolling Maturities (Abstract]
Due After One Year Through Five Years	83,436
Due After Five Year Through Ten Years	49,448
Due After Ten Years	10,888
Amortized Cost, Total	143,772
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Due After One Year Through Five Years	73,401
Due After Five Year Through Ten Years	41,783
Due After Ten Years	8,748
Fair Value, Total	123,932
Held-to-Maturity: Amortized Cost	5,202,698
Held-to-Maturity: Fair Value	4,411,003	4,615,393
Debt Securities Issued by Government Agencies
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-sale Securities: Amortized Cost	78,199
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	78,604
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	78,604
Residential - Government Agencies
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-sale Securities: Amortized Cost	771,006
Available-for-Sale: Amortized Cost	771,006	828,798
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	675,204
Available-for-Sale: Fair Value	675,204	732,828
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	1,761,490
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	1,761,490
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	675,204
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	1,470,627
Held-to-Maturity: Fair Value	1,470,627	1,554,227
Residential - U.S. Government-Sponsored Enterprises
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-sale Securities: Amortized Cost	869,381
Available-for-Sale: Amortized Cost	869,381	919,980
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	744,714
Available-for-Sale: Fair Value	744,714	793,871
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	2,856,709
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	2,856,709
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	744,714
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	2,469,057
Held-to-Maturity: Fair Value	2,469,057	2,571,275
Commercial - Government Agencies or Sponsored Agencies
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-sale Securities: Amortized Cost	163,474
Available-for-Sale: Amortized Cost	163,474	168,242
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	138,793
Available-for-Sale: Fair Value	138,793	145,667
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	440,727
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	440,727
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	138,793
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	347,387
Held-to-Maturity: Fair Value	347,387	361,994
Mortgage-Backed Securities
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-sale Securities: Amortized Cost	1,803,861
Available-for-Sale: Amortized Cost	1,803,861	1,917,020
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	1,558,711
Available-for-Sale: Fair Value	1,558,711	1,672,366
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	5,058,926
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	5,058,926
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	1,558,711
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	4,287,071
Held-to-Maturity: Fair Value	$ 4,287,071	$ 4,487,496