Investment Securities, AFS and HTM Securities Amortized Costs and Fair Values (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	$ 4,789,259	$ 4,605,954
Debt Securities, Available-for-Sale, Unrealized Gain	23,197	5,693
Debt Securities, Available-for-Sale, Unrealized Loss	(15,885)	(30,213)
Debt Securities, Available-for-Sale	4,796,570	4,581,434
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	3,705,857	3,738,747
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	40,432	42,653
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(572,119)	(595,906)
Debt Securities, Held-to-Maturity, Fair Value	3,174,170	3,185,494
US Treasury Securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	994	1,000
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	15	0
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	0	(1)
Debt Securities, Held-to-Maturity, Fair Value	1,009	999
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	3,063	3,063
Debt Securities, Available-for-Sale, Unrealized Gain	0	0
Debt Securities, Available-for-Sale, Unrealized Loss	(68)	(58)
Debt Securities, Available-for-Sale	2,995	3,005
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	1,649,045	1,659,722
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	662	1,122
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(194,901)	(174,202)
Debt Securities, Held-to-Maturity, Fair Value	1,454,805	1,486,642
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	0
Debt Securities, Available-for-Sale	0
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	320,057	324,182
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	7,786	8,135
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(59,642)	(65,963)
Debt Securities, Held-to-Maturity, Fair Value	268,201	266,353
Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	105,633	108,319
Debt Securities, Available-for-Sale, Unrealized Gain	52	123
Debt Securities, Available-for-Sale, Unrealized Loss	(911)	(604)
Debt Securities, Available-for-Sale	104,774	107,839
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Debt Securities, Held-to-Maturity, Fair Value	0
US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	427	495
Debt Securities, Available-for-Sale, Unrealized Gain	0	0
Debt Securities, Available-for-Sale, Unrealized Loss	(17)	(24)
Debt Securities, Available-for-Sale	410	471
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Debt Securities, Held-to-Maturity, Fair Value	0
Other Debt securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	3,000	3,000
Debt Securities, Available-for-Sale, Unrealized Gain	0	0
Debt Securities, Available-for-Sale, Unrealized Loss	(1)	(11)
Debt Securities, Available-for-Sale	2,999	2,989
US Government Sponsored-Enterprise Insured Loans | Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	125,024	120,272
Debt Securities, Available-for-Sale, Unrealized Gain	486	190
Debt Securities, Available-for-Sale, Unrealized Loss	(7,474)	(9,534)
Debt Securities, Available-for-Sale	118,036	110,928
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	871,331	885,476
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	21,973	22,934
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(169,482)	(186,464)
Debt Securities, Held-to-Maturity, Fair Value	723,822	721,946
US Government Sponsored-Enterprise Insured Loans | Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	18,240	18,332
Debt Securities, Available-for-Sale, Unrealized Gain	0	0
Debt Securities, Available-for-Sale, Unrealized Loss	(1,281)	(1,332)
Debt Securities, Available-for-Sale	16,959	17,000
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	770,177	772,456
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	9,765	10,217
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(139,208)	(159,078)
Debt Securities, Held-to-Maturity, Fair Value	640,734	623,595
Government National Mortgage Association (GNMA) [Member] | Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	4,418,218	4,236,199
Debt Securities, Available-for-Sale, Unrealized Gain	22,659	5,379
Debt Securities, Available-for-Sale, Unrealized Loss	(1,913)	(13,851)
Debt Securities, Available-for-Sale	4,438,964	4,227,727
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	42,972	43,693
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	14	9
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(3,009)	(3,774)
Debt Securities, Held-to-Maturity, Fair Value	39,977	39,927
Government National Mortgage Association (GNMA) [Member] | Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	115,654	116,275
Debt Securities, Available-for-Sale, Unrealized Gain	0	0
Debt Securities, Available-for-Sale, Unrealized Loss	(4,221)	(4,800)
Debt Securities, Available-for-Sale	111,433	111,475
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	51,281	52,219
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	218	236
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(5,877)	(6,424)
Debt Securities, Held-to-Maturity, Fair Value	$ 45,621	$ 46,032