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Securities Available for Sale and Held to Maturity - Securities with Gross Unrealized Losses, Segregated by Length of Impairment (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2025	Dec. 31, 2024
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	$ 311,459	$ 1,324,604
Gross Unrealized (Losses), Less than 12 Months	(936)	(18,989)
Estimated Fair Value, 12 Months or More	1,154,430	1,148,537
Gross Unrealized (Losses), 12 Months or More	(50,204)	(87,378)
Estimated Fair Value, Total	1,465,889	2,473,141
Gross Unrealized (Losses), Total	(51,140)	(106,367)
US Treasury Securities [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months		123,277
Gross Unrealized (Losses), Less than 12 Months		(1,925)
Estimated Fair Value, 12 Months or More		0
Gross Unrealized (Losses), 12 Months or More		0
Estimated Fair Value, Total		123,277
Gross Unrealized (Losses), Total		(1,925)
U.S. Government Agency Obligations [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	25,624	38,807
Gross Unrealized (Losses), Less than 12 Months	(313)	(2,387)
Estimated Fair Value, 12 Months or More	19,015	0
Gross Unrealized (Losses), 12 Months or More	(483)	0
Estimated Fair Value, Total	44,639	38,807
Gross Unrealized (Losses), Total	(796)	(2,387)
Residential Mortgage Pass-Through Securities Guaranteed by GNMA [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	1,212	15,802
Gross Unrealized (Losses), Less than 12 Months	(23)	(293)
Estimated Fair Value, 12 Months or More	29,230	27,803
Gross Unrealized (Losses), 12 Months or More	(2,523)	(3,508)
Estimated Fair Value, Total	30,442	43,605
Gross Unrealized (Losses), Total	(2,546)	(3,801)
Residential Mortgage Pass-Through Securities Issued by FNMA and FHLMC [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	284,623	981,747
Gross Unrealized (Losses), Less than 12 Months	(600)	(13,848)
Estimated Fair Value, 12 Months or More	228,922	237,487
Gross Unrealized (Losses), 12 Months or More	(21,155)	(32,199)
Estimated Fair Value, Total	513,545	1,219,234
Gross Unrealized (Losses), Total	(21,755)	(46,047)
Other Residential Mortgage-Backed Securities Issued or Guaranteed by FNMA, FHLMC or GNMA [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	0	0
Gross Unrealized (Losses), Less than 12 Months	0	0
Estimated Fair Value, 12 Months or More	98,247	115,681
Gross Unrealized (Losses), 12 Months or More	(4,794)	(8,004)
Estimated Fair Value, Total	98,247	115,681
Gross Unrealized (Losses), Total	(4,794)	(8,004)
Commercial Mortgage-Backed Securities Issued or Guaranteed by FNMA, FHLMC or GNMA [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	0	164,971
Gross Unrealized (Losses), Less than 12 Months	0	(536)
Estimated Fair Value, 12 Months or More	779,016	767,566
Gross Unrealized (Losses), 12 Months or More	(21,249)	(43,667)
Estimated Fair Value, Total	779,016	932,537
Gross Unrealized (Losses), Total	$ (21,249)	$ (44,203)

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- Definition

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