Investment Securities, HTM Credit Quality Indicators (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	$ 2,239,003	$ 1,879,005
Not Rated [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	896
U.S. Treasury securities
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	1,000	999
U.S. Treasury securities | Not Rated [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0
Obligations of state and political subdivisions (municipal securities)
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	1,628,759	1,441,900
Obligations of state and political subdivisions (municipal securities) | Not Rated [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	896
FNMA/FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	34,347	54,599
FNMA/FHLMC | Not Rated [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0
GNMA
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	48,053	114,553
GNMA | Not Rated [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0
Federal Home Loan Mortgage Corporation Certificates And Obligations (FHLMC) And Federal National Mortgage Association Certificates And Obligations (FNMA), Commercial [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	425,937	11,211
Federal Home Loan Mortgage Corporation Certificates And Obligations (FHLMC) And Federal National Mortgage Association Certificates And Obligations (FNMA), Commercial [Member] | Not Rated [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0
Government National Mortgage Association Certificates And Obligations (GNMA), Commercial [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	100,907	255,742
Government National Mortgage Association Certificates And Obligations (GNMA), Commercial [Member] | Not Rated [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0
AAA
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	1,312,642	1,004,357
AAA | U.S. Treasury securities
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	1,000	999
AAA | Obligations of state and political subdivisions (municipal securities)
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	702,399	567,252
AAA | FNMA/FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	34,347	54,599
AAA | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	48,053	114,553
AAA | Federal Home Loan Mortgage Corporation Certificates And Obligations (FHLMC) And Federal National Mortgage Association Certificates And Obligations (FNMA), Commercial [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	425,937	11,211
AAA | Government National Mortgage Association Certificates And Obligations (GNMA), Commercial [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	100,907	255,742
AA
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	914,591	860,607
AA | U.S. Treasury securities
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0	0
AA | Obligations of state and political subdivisions (municipal securities)
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	914,591	860,607
AA | FNMA/FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0	0
AA | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0	0
AA | Federal Home Loan Mortgage Corporation Certificates And Obligations (FHLMC) And Federal National Mortgage Association Certificates And Obligations (FNMA), Commercial [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0	0
AA | Government National Mortgage Association Certificates And Obligations (GNMA), Commercial [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0	0
A
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	10,873	14,041
A | U.S. Treasury securities
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0	0
A | Obligations of state and political subdivisions (municipal securities)
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	10,873	14,041
A | FNMA/FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0	0
A | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0	0
A | Federal Home Loan Mortgage Corporation Certificates And Obligations (FHLMC) And Federal National Mortgage Association Certificates And Obligations (FNMA), Commercial [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	0	0
A | Government National Mortgage Association Certificates And Obligations (GNMA), Commercial [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment securities held to maturity	$ 0	$ 0