Fair Value Measurements Details of Book Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
AFS, at estimated fair value	$ 2,572,721	$ 2,646,767
Debt Securities, Held-to-Maturity, Fair Value	1,086,692	1,125,049
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and due from banks	504,702	681,921
FRB and FHLB stock	124,218	130,186
Loans held for sale	14,673	7,264
AFS, at estimated fair value	2,572,721	2,646,767
Debt Securities, Held-to-Maturity, Fair Value	1,294,613	1,321,256
Net Loans	20,757,243	20,010,181
Accrued interest receivable	96,991	91,579
Other financial assets	675,328	642,049
Demand and savings deposits	18,055,623	18,851,912
Brokered deposits	949,259	208,416
Time deposits	2,201,658	1,589,210
Accrued interest payable	24,101	10,185
Federal funds purchased	555,000	191,000
Federal Home Loan Bank advances	1,165,000	1,250,000
Senior debt and subordinated debt	539,994	539,634
Other borrowings	459,120	890,573
Other financial liabilities	454,641	467,705
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and due from banks	504,702	681,921
FRB and FHLB stock	124,218	130,186
Loans held for sale	14,673	7,264
AFS, at estimated fair value	2,572,721	2,646,767
Debt Securities, Held-to-Maturity, Fair Value	1,086,692	1,125,049
Net Loans	19,233,430	18,862,701
Accrued interest receivable	96,991	91,579
Other financial assets	675,328	642,049
Demand and savings deposits	18,055,623	18,851,912
Brokered deposits	947,399	213,501
Time deposits	2,182,337	1,574,747
Accrued interest payable	24,101	10,185
Federal funds purchased	555,003	190,998
Federal Home Loan Bank advances	1,164,991	1,249,629
Senior debt and subordinated debt	461,365	456,867
Other borrowings	459,097	890,573
Other financial liabilities	454,641	467,705
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	504,702	681,921
FRB and FHLB stock	0	0
Loans held for sale	0	0
AFS, at estimated fair value	220,638	218,485
Debt Securities, Held-to-Maturity, Fair Value	0	0
Net Loans	0	0
Accrued interest receivable	96,991	91,579
Other financial assets	447,924	419,419
Demand and savings deposits	18,055,623	18,851,912
Brokered deposits	150,222	188,416
Time deposits	0	0
Accrued interest payable	24,101	10,185
Federal funds purchased	555,003	190,998
Federal Home Loan Bank advances	1,164,991	1,249,629
Senior debt and subordinated debt	0	0
Other borrowings	458,087	889,393
Other financial liabilities	146,849	154,912
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	124,218	130,186
Loans held for sale	14,673	7,264
AFS, at estimated fair value	2,352,083	2,428,282
Debt Securities, Held-to-Maturity, Fair Value	1,086,692	1,125,049
Net Loans	0	0
Accrued interest receivable	0	0
Other financial assets	174,079	166,796
Demand and savings deposits	0	0
Brokered deposits	797,177	25,085
Time deposits	2,182,337	1,574,747
Accrued interest payable	0	0
Federal funds purchased	0	0
Federal Home Loan Bank advances	0	0
Senior debt and subordinated debt	461,365	456,867
Other borrowings	1,010	1,180
Other financial liabilities	291,224	296,465
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	19,233,430	18,862,701
Accrued interest receivable	0	0
Other financial assets	53,325	55,834
Demand and savings deposits	0	0
Brokered deposits	0	0
Time deposits	0	0
Accrued interest payable	0	0
Federal funds purchased	0	0
Federal Home Loan Bank advances	0	0
Senior debt and subordinated debt	0	0
Other borrowings	0	0
Other financial liabilities	$ 16,568	$ 16,328