Fair Value Measurements Details of Book Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
AFS, at estimated fair value	$ 3,313,296	$ 2,398,352
Debt Securities, Held-to-Maturity, Fair Value	1,064,304	1,072,207
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and due from banks	1,440,680	549,710
FRB and FHLB stock	143,212	124,405
Loans held for sale	17,678	15,158
AFS, at estimated fair value	3,313,296	2,398,352
Debt Securities, Held-to-Maturity, Fair Value	1,231,982	1,267,922
Net Loans	23,800,114	21,057,690
Accrued interest receivable	115,903	107,972
Other financial assets	705,318	661,067
Demand and savings deposits	21,021,766	17,653,690
Brokered deposits	843,473	1,144,692
Time deposits	4,286,905	2,739,241
Accrued interest payable	36,723	35,083
Federal funds purchased		240,000
Federal Home Loan Bank advances	950,000	1,100,000
Senior debt and subordinated debt	535,917	535,384
Other borrowings	566,310	612,142
Other financial liabilities	394,068	429,046
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and due from banks	1,440,680	549,710
FRB and FHLB stock	143,212	124,405
Loans held for sale	17,678	15,158
AFS, at estimated fair value	3,313,296	2,398,352
Debt Securities, Held-to-Maturity, Fair Value	1,064,304	1,072,207
Net Loans	22,681,492	19,930,560
Accrued interest receivable	115,903	107,972
Other financial assets	726,160	661,067
Demand and savings deposits	21,021,766	17,653,690
Brokered deposits	843,750	1,145,379
Time deposits	4,298,383	2,714,709
Accrued interest payable	36,723	35,083
Federal funds purchased		240,000
Federal Home Loan Bank advances	941,539	1,094,013
Senior debt and subordinated debt	435,761	463,270
Other borrowings	566,296	612,106
Other financial liabilities	394,213	429,046
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and due from banks	1,440,680	549,710
FRB and FHLB stock	0	0
Loans held for sale	0	0
AFS, at estimated fair value	0	42,161
Debt Securities, Held-to-Maturity, Fair Value	0	0
Net Loans	0	0
Accrued interest receivable	115,903	107,972
Other financial assets	537,530	452,935
Demand and savings deposits	21,021,766	17,653,690
Brokered deposits	137,879	145,987
Time deposits	0	0
Accrued interest payable	36,723	35,083
Federal funds purchased		240,000
Federal Home Loan Bank advances	941,539	1,094,013
Senior debt and subordinated debt	0	0
Other borrowings	565,285	611,269
Other financial liabilities	177,160	165,635
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and due from banks	0	0
FRB and FHLB stock	143,212	124,405
Loans held for sale	17,678	15,158
AFS, at estimated fair value	3,313,296	2,356,191
Debt Securities, Held-to-Maturity, Fair Value	1,064,304	1,072,207
Net Loans	0	0
Accrued interest receivable	0	0
Other financial assets	136,815	157,540
Demand and savings deposits	0	0
Brokered deposits	705,871	999,392
Time deposits	4,298,383	2,714,709
Accrued interest payable	0	0
Federal funds purchased		0
Federal Home Loan Bank advances	0	0
Senior debt and subordinated debt	435,761	463,270
Other borrowings	1,011	837
Other financial liabilities	202,865	246,157
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and due from banks	0	0
FRB and FHLB stock	0	0
Loans held for sale	0	0
AFS, at estimated fair value	0	0
Debt Securities, Held-to-Maturity, Fair Value	0	0
Net Loans	22,681,492	19,930,560
Accrued interest receivable	0	0
Other financial assets	51,815	50,592
Demand and savings deposits	0	0
Brokered deposits	0	0
Time deposits	0	0
Accrued interest payable	0	0
Federal funds purchased		0
Federal Home Loan Bank advances	0	0
Senior debt and subordinated debt	0	0
Other borrowings	0	0
Other financial liabilities	$ 14,188	$ 17,254