Fair Value Measurements (Carrying Value and Fair Value of Financial Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Assets:
Investment securities	$ 8,946,420	$ 8,877,281
Non-marketable equity securities	223,159	310,084
Liabilities:
Time deposits	4,463,394	5,163,995
Fair Value, Inputs, Level 1
Assets:
Cash and cash equivalents	433,452	588,283
Fair Value, Inputs, Level 2
Assets:
Non-marketable equity securities	$ 223,159	$ 310,084
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Liabilities:
Demand, savings and money market deposits	$ 23,300,213	$ 21,374,483
Time deposits	4,425,169	5,133,119
FHLB advances	3,284,943	5,115,637
Notes and other borrowings	$ 670,782	$ 676,077
Derivative liabilities	Other liabilities	Other liabilities
Fair Value, Inputs, Level 3
Assets:
Loans, net	$ 22,991,951	$ 23,075,192
Carrying Value
Assets:
Cash and cash equivalents	433,452	588,283
Investment securities	8,946,449	8,877,354
Non-marketable equity securities	223,159	310,084
Loans, net	$ 24,402,786	$ 24,430,995
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Liabilities:
Demand, savings and money market deposits	$ 23,300,213	$ 21,374,483
Time deposits	4,463,394	5,163,995
FHLB advances	3,285,000	5,115,000
Notes and other borrowings	$ 708,835	$ 708,973
Derivative liabilities	Other liabilities	Other liabilities