Securities (Amortized Cost and Fair Value of Debt Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Investments Debt And Equity Securities [Abstract]
Debt Securities Available for Sale, Due in one year or less, Amortized Cost	$ 112
Debt Securities Available for Sale, Due after one year through five years, Amortized Cost	919,639
Debt Securities Available for Sale, Due after five years through ten years, Amortized Cost	2,982,549
Debt Securities Available for Sale, Due after ten years, Amortized Cost	2,407,914
Securities Available for Sale, Gross Amortized Cost	6,310,214	$ 6,984,530
Debt Securities Available for Sale, Due in one year or less, Fair Value	111
Debt Securities Available for Sale, Due after one year through five years, Fair Value	871,760
Debt Securities Available for Sale, Due after five years through ten years, Fair Value	2,665,232
Debt Securities Available for Sale, Due after ten years, Fair Value	2,018,938
Total available for sale debt securities, Fair Value	5,556,041	6,986,698
Debt Securities Held to Maturity, Due in one year or less, Amortized Cost	10,000
Debt Securities Held to Maturity, Due after one year through five years, Amortized Cost	544,146
Debt Securities Held to Maturity, Due after five years through ten years, Amortized Cost	893,562
Debt Securities Held to Maturity, Due after ten years, Amortized Cost	1,404,787
Total held to maturity debt securities, Amortized Cost	2,852,495	1,565,751
Debt Securities Held to Maturity, Due in one year or less, Fair Value	9,924
Debt Securities Held to Maturity, Due after one year through five years, Fair Value	522,347
Debt Securities Held to Maturity, Due after five years through ten years, Fair Value	813,726
Debt Securities Held to Maturity, Due after ten years, Fair Value	1,269,401
Total held to maturity debt securities, Fair Value	$ 2,615,398	$ 1,631,482