Investment Securities Schedule of Amortized Cost and Fair Values of Debt Securities by Contractual Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Amortized Cost
Due in one year or less	$ 9,524
Due from one year to five years	287,824
Due from five years to ten years	506,946
Due after ten years	1,146,781
Amortized cost, before securities without debt maturities	1,951,075
Amortized Cost	3,008,323
Estimated Fair Value
Due in one year or less	9,516
Due from one year to five years	277,609
Due from five years to ten years	463,474
Due after ten years	906,391
Available for sale securities, debt maturities, before securities without single maturities	1,656,990
Estimated Fair Value	2,597,384	$ 3,187,390
Amortized Cost
Due in one year or less	0
Due from one year to five years	0
Due from five years to ten years	0
Due after ten years	0
Debt securities, held-to-maturity, maturity, allocated and single maturity date, amortized cost, total	0
Amortized Cost, Held to Maturity	1,339,310	980,384
Estimated Fair Value
Due in one year or less	0
Due from one year to five years	0
Due from five years to ten years	0
Due after ten years	0
Debt securities, held-to-maturity, maturity, Allocated and single maturity date, fair value	0
Estimated Fair Value, Held to Maturity	1,141,710	965,867
Mortgage-Backed Securities [Member]
Amortized Cost
Available-for-sale securities, amortized cost without single maturity date	246,854
Amortized Cost	246,854	231,607
Estimated Fair Value
Available-for-sale securities, debt maturities, without single maturity date, fair value	214,252
Estimated Fair Value	214,252	229,795
Amortized Cost
Debt securities, held-to-maturity, maturity, without single maturity date, amortized cost	470,879
Amortized Cost, Held to Maturity	470,879	404,958
Estimated Fair Value
Debt securities, held-to-maturity, maturity, without single maturity date, fair value	409,998
Estimated Fair Value, Held to Maturity	409,998	408,913
Commercial Mortgage Backed Securities [Member]
Amortized Cost
Available-for-sale securities, amortized cost without single maturity date	655,384
Amortized Cost	655,384	974,541
Estimated Fair Value
Available-for-sale securities, debt maturities, without single maturity date, fair value	583,741
Estimated Fair Value	583,741	971,148
Amortized Cost
Debt securities, held-to-maturity, maturity, without single maturity date, amortized cost	868,431
Amortized Cost, Held to Maturity	868,431	575,426
Estimated Fair Value
Debt securities, held-to-maturity, maturity, without single maturity date, fair value	731,712
Estimated Fair Value, Held to Maturity	731,712	556,954
Collateralized Mortgage Obligations [Member]
Amortized Cost
Available-for-sale securities, amortized cost without single maturity date	155,010
Amortized Cost	155,010	206,532
Estimated Fair Value
Available-for-sale securities, debt maturities, without single maturity date, fair value	142,401
Estimated Fair Value	142,401	$ 209,359
Amortized Cost
Debt securities, held-to-maturity, maturity, without single maturity date, amortized cost	0
Estimated Fair Value
Debt securities, held-to-maturity, maturity, without single maturity date, fair value	$ 0