Fair Value Measurements Details of Book Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
AFS, at estimated fair value	$ 3,187,390	$ 3,062,143
Estimated Fair Value	965,867
Carrying Amount
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and cash equivalents	1,638,614	1,847,832
FRB and FHLB stock	57,635	92,129
Loans held for sale	35,768	83,886
AFS, at estimated fair value	980,384	278,281
Estimated Fair Value	3,187,390	3,062,143
Net Loans	18,076,349	18,623,253
Accrued interest receivable	57,451	72,942
Other assets	565,491	650,425
Demand and savings deposits	19,594,497	18,279,358
Brokered deposits	251,526	335,185
Time deposits	1,727,476	2,224,664
Accrued interest payable	7,000	10,365
Short-term borrowings	416,764	630,066
Long-term borrowings	621,345	1,296,263
Other liabilities	288,862	338,747
Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and cash equivalents	1,638,614	1,847,832
FRB and FHLB stock	57,635	92,129
Loans held for sale	35,768	83,886
AFS, at estimated fair value	965,867	296,857
Estimated Fair Value	3,187,390	3,062,143
Net Loans	17,519,497	18,354,532
Accrued interest receivable	57,451	72,942
Other assets	565,491	650,425
Demand and savings deposits	19,594,497	18,279,358
Brokered deposits	252,129	336,391
Time deposits	1,730,673	2,246,457
Accrued interest payable	7,000	10,365
Short-term borrowings	416,764	630,066
Long-term borrowings	605,719	1,332,041
Other liabilities	288,862	338,747
Level 1 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and cash equivalents	1,638,614	1,847,832
FRB and FHLB stock	0	0
Loans held for sale	0	0
AFS, at estimated fair value	0	0
Estimated Fair Value	127,618	0
Net Loans	0	0
Accrued interest receivable	57,451	72,942
Other assets	367,336	279,015
Demand and savings deposits	19,594,497	18,279,358
Brokered deposits	231,526	295,185
Time deposits	0	0
Accrued interest payable	7,000	10,365
Short-term borrowings	416,764	630,066
Long-term borrowings	0	0
Other liabilities	188,219	156,869
Level 2 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and cash equivalents	0	0
FRB and FHLB stock	57,635	92,129
Loans held for sale	35,768	83,886
AFS, at estimated fair value	965,867	296,857
Estimated Fair Value	2,985,105	2,963,937
Net Loans	0	0
Accrued interest receivable	0	0
Other assets	160,945	338,987
Demand and savings deposits	0	0
Brokered deposits	20,603	41,206
Time deposits	1,730,673	2,246,457
Accrued interest payable	0	0
Short-term borrowings	0	0
Long-term borrowings	605,719	1,332,041
Other liabilities	86,110	167,505
Level 3 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, FinancialStatement Captions[Line Items]
Cash and cash equivalents	0	0
FRB and FHLB stock	0	0
Loans held for sale	0	0
AFS, at estimated fair value	0	0
Estimated Fair Value	74,667	98,206
Net Loans	17,519,497	18,354,532
Accrued interest receivable	0	0
Other assets	37,210	32,423
Demand and savings deposits	0	0
Brokered deposits	0	0
Time deposits	0	0
Accrued interest payable	0	0
Short-term borrowings	0	0
Long-term borrowings	0	0
Other liabilities	$ 14,533	$ 14,373