Investment Securities - Schedule of AFS Debt Securities in an Unrealized Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Less Than 12 Months, Fair Value	$ 283,698	$ 1,206,152
Less Than 12 Months, Gross Unrealized Losses	(2,509)	(76,494)
12 Months or Longer, Fair Value	2,158,430	1,449,762
12 Months or Longer, Gross Unrealized Losses	(294,564)	(252,970)
Total Fair Value	2,442,128	2,655,914
Total Gross Unrealized Losses	(297,073)	(329,464)
Debt Securities Issued by the U.S. Treasury and Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Less Than 12 Months, Fair Value	11,940	28,574
Less Than 12 Months, Gross Unrealized Losses	(37)	(1,118)
12 Months or Longer, Fair Value	148,474	127,841
12 Months or Longer, Gross Unrealized Losses	(12,527)	(13,949)
Total Fair Value	160,414	156,415
Total Gross Unrealized Losses	(12,564)	(15,067)
Debt Securities Issued by States and Political Subdivisions
Schedule Of Available For Sale Securities [Line Items]
Less Than 12 Months, Fair Value	8,041	11,341
Less Than 12 Months, Gross Unrealized Losses	(16)	(1,240)
12 Months or Longer, Fair Value	62,948	49,985
12 Months or Longer, Gross Unrealized Losses	(10,359)	(11,342)
Total Fair Value	70,989	61,326
Total Gross Unrealized Losses	(10,375)	(12,582)
Debt Securities Issued by Government-Sponsored Enterprises
Schedule Of Available For Sale Securities [Line Items]
Less Than 12 Months, Fair Value	47,004	47,825
Less Than 12 Months, Gross Unrealized Losses	(46)	(108)
12 Months or Longer, Fair Value	1,652	803
12 Months or Longer, Gross Unrealized Losses	(105)	(71)
Total Fair Value	48,656	48,628
Total Gross Unrealized Losses	(151)	(179)
Debt Securities Issued by Corporations
Schedule Of Available For Sale Securities [Line Items]
Less Than 12 Months, Fair Value	149,430	438,225
Less Than 12 Months, Gross Unrealized Losses	(570)	(7,995)
12 Months or Longer, Fair Value	376,921	284,350
12 Months or Longer, Gross Unrealized Losses	(51,206)	(48,741)
Total Fair Value	526,351	722,575
Total Gross Unrealized Losses	(51,776)	(56,736)
Residential - Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Less Than 12 Months, Fair Value	56,131	386,809
Less Than 12 Months, Gross Unrealized Losses	(1,453)	(30,492)
12 Months or Longer, Fair Value	652,088	340,824
12 Months or Longer, Gross Unrealized Losses	(84,932)	(65,723)
Total Fair Value	708,219	727,633
Total Gross Unrealized Losses	(86,385)	(96,215)
Residential - U.S. Government-Sponsored Enterprises
Schedule Of Available For Sale Securities [Line Items]
Less Than 12 Months, Fair Value	10,399	194,684
Less Than 12 Months, Gross Unrealized Losses	(365)	(22,294)
12 Months or Longer, Fair Value	772,000	598,986
12 Months or Longer, Gross Unrealized Losses	(113,624)	(103,816)
Total Fair Value	782,399	793,670
Total Gross Unrealized Losses	(113,989)	(126,110)
Commercial - Government Agencies or Sponsored Agencies
Schedule Of Available For Sale Securities [Line Items]
Less Than 12 Months, Fair Value	753	98,694
Less Than 12 Months, Gross Unrealized Losses	(22)	(13,247)
12 Months or Longer, Fair Value	144,347	46,973
12 Months or Longer, Gross Unrealized Losses	(21,811)	(9,328)
Total Fair Value	145,100	145,667
Total Gross Unrealized Losses	(21,833)	(22,575)
Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Less Than 12 Months, Fair Value	67,283	680,187
Less Than 12 Months, Gross Unrealized Losses	(1,840)	(66,033)
12 Months or Longer, Fair Value	1,568,435	986,783
12 Months or Longer, Gross Unrealized Losses	(220,367)	(178,867)
Total Fair Value	1,635,718	1,666,970
Total Gross Unrealized Losses	$ (222,207)	$ (244,900)