Investment Securities - Analysis of the Contractual Maturities of Investment Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Amortized Cost
Due in One Year or Less	$ 126,856
Due After One Year Through Five Years	629,712
Due After Five Years Through Ten Years	208,634
Amortized Cost, Total	965,202
Available-for-Sale: Amortized Cost	3,313,974	$ 2,947,415
Fair Value
Due in One Year or Less	124,752
Due After One Year Through Five Years	615,325
Due After Five Years Through Ten Years	189,655
Fair Value, Total	929,732
Available-for-Sale: Fair Value	3,111,504	2,689,528
Amortized Cost
Due in One Year or Less	7,500
Due After One Year Through Five Years	74,843
Due After Five Year Through Ten Years	59,943
Amortized Cost, Total	142,286
Held-to-Maturity: Amortized Cost	4,441,353	4,618,543
Fair Value
Due in One Year or Less	7,411
Due After One Year Through Five Years	70,099
Due After Five Year Through Ten Years	52,195
Fair Value, Total	129,705
Held-to-Maturity: Fair Value	3,754,794	3,820,882
Debt Securities Issued by Government Agencies
Amortized Cost
Available-for-sale Securities: Amortized Cost	109,473
Fair Value
Available-for-sale Securities, Fair Value	109,770
Total Collateralized Mortgage Obligations
Amortized Cost
Available-for-sale Securities: Amortized Cost	1,582,011
Available-for-Sale: Amortized Cost	1,582,011	1,356,995
Fair Value
Available-for-sale Securities, Fair Value	1,465,837
Available-for-Sale: Fair Value	1,465,837	1,218,694
Amortized Cost
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	2,504,103
Held-to-Maturity: Amortized Cost	2,504,103	2,601,599
Fair Value
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	2,095,443
Held-to-Maturity: Fair Value	2,095,443	2,132,242
Residential - Government Agencies or Sponsored Agencies
Amortized Cost
Available-for-sale Securities: Amortized Cost	1,191,950
Available-for-Sale: Amortized Cost	1,191,950	1,050,299
Fair Value
Available-for-sale Securities, Fair Value	1,097,369
Available-for-Sale: Fair Value	1,097,369	935,220
Amortized Cost
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	2,092,255
Held-to-Maturity: Amortized Cost	2,092,255	2,185,210
Fair Value
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	1,766,608
Held-to-Maturity: Fair Value	1,766,608	1,808,064
Commercial - Government Agencies or Sponsored Agencies
Amortized Cost
Available-for-sale Securities: Amortized Cost	354,093
Available-for-Sale: Amortized Cost	354,093	306,696
Fair Value
Available-for-sale Securities, Fair Value	332,461
Available-for-Sale: Fair Value	332,461	283,474
Amortized Cost
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	411,848
Held-to-Maturity: Amortized Cost	411,848	416,389
Fair Value
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	328,835
Held-to-Maturity: Fair Value	328,835	324,178
Commercial - Non-Agency
Amortized Cost
Available-for-sale Securities: Amortized Cost	35,968
Available-for-Sale: Amortized Cost	35,968
Fair Value
Available-for-sale Securities, Fair Value	36,007
Available-for-Sale: Fair Value	36,007
Total Mortgage-Backed Securities
Amortized Cost
Available-for-sale Securities: Amortized Cost	657,288
Available-for-Sale: Amortized Cost	657,288	555,092
Fair Value
Available-for-sale Securities, Fair Value	606,165
Available-for-Sale: Fair Value	606,165	484,764
Amortized Cost
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	1,794,964
Held-to-Maturity: Amortized Cost	1,794,964	1,874,586
Fair Value
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	1,529,646
Held-to-Maturity: Fair Value	1,529,646	1,563,365
Residential - Government Agencies or Sponsored Agencies
Amortized Cost
Available-for-sale Securities: Amortized Cost	657,288
Available-for-Sale: Amortized Cost	657,288	555,092
Fair Value
Available-for-sale Securities, Fair Value	606,165
Available-for-Sale: Fair Value	606,165	484,764
Amortized Cost
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	1,784,975
Held-to-Maturity: Amortized Cost	1,784,975	1,864,591
Fair Value
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	1,521,492
Held-to-Maturity: Fair Value	1,521,492	1,555,535
Commercial - Government Agencies or Sponsored Enterprises
Amortized Cost
Held-to-Maturity: Mortgage-Backed Securities: Amortized Cost	9,989
Held-to-Maturity: Amortized Cost	9,989	9,995
Fair Value
Held-to-Maturity: Mortgage-Backed Securities: Fair Value	8,154
Held-to-Maturity: Fair Value	$ 8,154	$ 7,830