Investment Securities - Analysis of the Contractual Maturities of Investment Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis Rolling Maturity[Abstract]
Due in One Year or Less	$ 433
Due After One Year Through Five Years	277,971
Due After Five Years Through Ten Years	371,893
Due After Ten Years	13,130
Amortized Cost, Total	663,427
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-Sale: Amortized Cost	2,752,364	$ 4,320,884
Due in One Year or Less	429
Due After One Year Through Five Years	255,858
Due After Five Years Through Ten Years	307,504
Due After Ten Years	10,251
Fair Value, Total	574,042
Available-for-Sale: Fair Value	2,424,608	4,276,056
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis, Rolling Maturities (Abstract]
Due After One Year Through Five Years	14,260
Due After Five Year Through Ten Years	124,087
Due After Ten Years	11,085
Amortized Cost, Total	149,432
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Due After One Year Through Five Years	13,208
Due After Five Year Through Ten Years	105,737
Due After Ten Years	8,785
Fair Value, Total	127,730
Held-to-Maturity: Amortized Cost	5,461,160
Held-to-Maturity: Fair Value	4,668,074	4,646,619
Debt Securities Issued by Government Agencies
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-sale Securities: Amortized Cost	102,889
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	103,709
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	103,709
Residential - Government Agencies
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-sale Securities: Amortized Cost	864,919
Available-for-Sale: Amortized Cost	864,919	1,327,990
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	775,687
Available-for-Sale: Fair Value	775,687	1,319,042
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	1,900,988
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	1,900,988
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	775,687
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	1,624,139
Held-to-Maturity: Fair Value	1,624,139	1,755,912
Residential - U.S. Government-Sponsored Enterprises
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-sale Securities: Amortized Cost	949,497
Available-for-Sale: Amortized Cost	949,497	2,127,781
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	819,685
Available-for-Sale: Fair Value	819,685	2,090,326
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	2,958,051
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	2,958,051
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	819,685
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	2,546,621
Held-to-Maturity: Fair Value	2,546,621	2,269,761
Commercial - Government Agencies or Sponsored Agencies
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-sale Securities: Amortized Cost	171,632
Available-for-Sale: Amortized Cost	171,632	155,164
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	151,485
Available-for-Sale: Fair Value	151,485	155,890
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	452,689
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	452,689
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	151,485
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	369,584
Held-to-Maturity: Fair Value	369,584	469,664
Mortgage-Backed Securities
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturities [Abstract]
Available-for-sale Securities: Amortized Cost	1,986,048
Available-for-Sale: Amortized Cost	1,986,048	3,610,935
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	1,746,857
Available-for-Sale: Fair Value	1,746,857	3,565,258
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Fair Value, Rolling Maturities [Abstract]
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	5,311,728
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	5,311,728
Available-for-sale Securities, Debt Securities Issued by Government Agencies and Mortgage-Backed Securities: Fair Value	1,746,857
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	4,540,344
Held-to-Maturity: Fair Value	$ 4,540,344	$ 4,495,337