Securities (Amortized Cost and Fair Value of Debt Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Debt Securities Available for Sale, Due in one year or less, Amortized Cost	$ 30,778
Debt Securities Available for Sale, Due after one year through five years, Amortized Cost	1,612,998
Debt Securities Available for Sale, Due after five years through ten years, Amortized Cost	1,904,156
Debt Securities Available for Sale, Due after ten years, Amortized Cost	2,655,522
Securities Available for Sale, Amortized Cost	6,203,454	$ 5,774,133
Debt Securities Available for Sale, Due in one year or less, Fair Value	30,776
Debt Securities Available for Sale, Due after one year through five years, Fair Value	1,576,482
Debt Securities Available for Sale, Due after five years through ten years, Fair Value	1,787,534
Debt Securities Available for Sale, Due after ten years, Fair Value	2,398,878
Total debt securities available for sale, Fair Value	5,793,670	5,161,491
Debt Securities Held to Maturity, Due in one year or less, Amortized Cost	134,954
Debt Securities Held to Maturity, Due after one year through five years, Amortized Cost	680,676
Debt Securities Held to Maturity, Due after five years through ten years, Amortized Cost	507,188
Debt Securities Held to Maturity, Due after ten years, Amortized Cost	874,793
Securities Held to Maturity, Gross Amortized Cost	2,197,611	2,435,663
Debt Securities Held to Maturity, Due in one year or less, Fair Value	133,941
Debt Securities Held to Maturity, Due after one year through five years, Fair Value	660,373
Debt Securities Held to Maturity, Due after five years through ten years, Fair Value	482,174
Debt Securities Held to Maturity, Due after ten years, Fair Value	788,103
Total debt securities held to maturity, Fair Value	$ 2,064,591	$ 2,233,526