Investment Securities - Analysis of the Contractual Maturities of Investment Securities (Details) - USD ($) $ in Thousands	Mar. 31, 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	$ 8,904
Due After One Year Through Five Years	58,719
Due After Five Years Through Ten Years	728,368
Due After Ten Years	6,380
Amortized Cost, Total	1,163,059
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-Sale: Amortized Cost	3,109,778	$ 3,172,436
Due in One Year or Less	8,864
Due After One Year Through Five Years	52,706
Due After Five Years Through Ten Years	675,121
Due After Ten Years	5,207
Fair Value, Total	1,089,872
Available-for-Sale: Fair Value	2,815,083	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	419,407
Due After Five Year Through Ten Years	74,373
Due After Ten Years	10,954
Amortized Cost, Total	144,046
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Due After One Year Through Five Years	400,680
Due After Five Year Through Ten Years	64,940
Due After Ten Years	8,983
Fair Value, Total	126,629
Held-to-Maturity: Amortized Cost	5,312,815
Held-to-Maturity: Fair Value	4,601,876	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	83,468
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	83,930
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	83,930
Residential - Government Agencies
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-sale Securities: Amortized Cost	799,732
Available-for-Sale: Amortized Cost	799,732	828,798
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	713,582
Available-for-Sale: Fair Value	713,582	732,828
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	1,807,744
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	1,807,744
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	713,582
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	1,554,547
Held-to-Maturity: Fair Value	1,554,547	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	896,586
Available-for-Sale: Amortized Cost	896,586	919,980
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	782,599
Available-for-Sale: Fair Value	782,599	793,871
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	2,916,693
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	2,916,693
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	782,599
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	2,560,572
Held-to-Maturity: Fair Value	2,560,572	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	166,933
Available-for-Sale: Amortized Cost	166,933	168,242
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	145,100
Available-for-Sale: Fair Value	145,100	145,667
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	444,332
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	444,332
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	145,100
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	360,128
Held-to-Maturity: Fair Value	360,128	361,994
Mortgage-Backed Securities
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-sale Securities: Amortized Cost	1,863,251
Available-for-Sale: Amortized Cost	1,863,251	1,917,020
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	1,641,281
Available-for-Sale: Fair Value	1,641,281	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	5,168,769
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	5,168,769
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	1,641,281
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	4,475,247
Held-to-Maturity: Fair Value	$ 4,475,247	$ 4,487,496