Loans and Allowance for Credit Losses on Loans - Allowance Activity (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 253,469	$ 211,866
Provision for credit losses on loans	27,369	(1,227)
Charge-offs	20,732	460
Recoveries	822	972
Net charge-offs (recoveries)	19,910	(512)
Ending balance	260,928	211,151
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	136,841	102,202
Provision for credit losses on loans	32,475	5,437
Charge-offs	20,732	110
Recoveries	816	217
Net charge-offs (recoveries)	19,916	(107)
Ending balance	149,400	107,746
Energy
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	49,000	52,568
Provision for credit losses on loans	1,930	(24,522)
Charge-offs	0	0
Recoveries	6	755
Net charge-offs (recoveries)	(6)	(755)
Ending balance	50,936	28,801
Mortgage Finance
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	10,745	6,083
Provision for credit losses on loans	(3,345)	4,159
Charge-offs	0	0
Recoveries	0	0
Net charge-offs (recoveries)	0	0
Ending balance	7,400	10,242
Real Estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	56,883	51,013
Provision for credit losses on loans	(3,691)	13,699
Charge-offs	0	350
Recoveries	0	0
Net charge-offs (recoveries)	0	350
Ending balance	$ 53,192	$ 64,362

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
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-Name Accounting Standards Codification
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- Definition

Amount, excluding accrued interest, of increase (decrease) in allowance for credit loss on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
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-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

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Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

+ References

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Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of expense related to estimated loss from loan and lease transactions.

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