Securities (Amortized Cost and Fair Value of Debt Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Debt Securities Available for Sale, Due in one year or less, Amortized Cost	$ 66,226
Debt Securities Available for Sale, Due after one year through five years, Amortized Cost	946,854
Debt Securities Available for Sale, Due after five years through ten years, Amortized Cost	2,292,196
Debt Securities Available for Sale, Due after ten years, Amortized Cost	2,440,004
Securities Available for Sale, Amortized Cost	5,745,280	$ 5,496,718
Debt Securities Available for Sale, Due in one year or less, Fair Value	66,092
Debt Securities Available for Sale, Due after one year through five years, Fair Value	934,210
Debt Securities Available for Sale, Due after five years through ten years, Fair Value	2,121,901
Debt Securities Available for Sale, Due after ten years, Fair Value	2,173,944
Total available for sale debt securities, Fair Value	5,296,147	4,915,195
Debt Securities Held to Maturity, Due in one year or less, Amortized Cost	95,237
Debt Securities Held to Maturity, Due after one year through five years, Amortized Cost	791,983
Debt Securities Held to Maturity, Due after five years through ten years, Amortized Cost	581,877
Debt Securities Held to Maturity, Due after ten years, Amortized Cost	1,004,536
Securities Held to Maturity, Gross Amortized Cost	2,473,633	2,684,779
Debt Securities Held to Maturity, Due in one year or less, Fair Value	94,381
Debt Securities Held to Maturity, Due after one year through five years, Fair Value	763,985
Debt Securities Held to Maturity, Due after five years through ten years, Fair Value	554,189
Debt Securities Held to Maturity, Due after ten years, Fair Value	912,703
Total held to maturity debt securities, Fair Value	$ 2,325,258	$ 2,485,918