Loans - Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	$ 62,173	$ 85,136	$ 64,586	$ 86,670
Charge-offs	2,192	3,010	4,594	6,037
Recoveries	639	202	1,287	335
Provision	2,503	(5,224)	1,844	(3,864)
Ending Balance	63,123	77,104	63,123	77,104
Average Balance	$ 5,242,567	$ 5,509,593	$ 5,150,007	$ 5,580,580
Net charge-offs to loan average balance	0.12%	0.20%	0.13%	0.21%
Provision (benefit) for credit losses	$ 3,500	$ (5,600)	$ 3,100	$ (4,200)
Provision (release) for off-balance sheet commitments	408	(390)	556	(338)
Credit loss expense (benefit)	540	5	725	5
Real estate \| Commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	14,606	18,397	13,425	15,430
Charge-offs	0	102	166	130
Recoveries	0	3	2	6
Provision	1,506	(2,016)	2,851	976
Ending Balance	16,112	16,282	16,112	16,282
Average Balance	$ 1,773,784	$ 1,465,799	$ 1,828,700	$ 1,443,931
Net charge-offs to loan average balance	0.00%	0.03%	0.02%	0.02%
Real estate \| Construction/land/land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	$ 4,580	$ 7,389	$ 4,011	$ 8,191
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	127	(1,787)	696	(2,589)
Ending Balance	4,707	5,602	4,707	5,602
Average Balance	$ 576,672	$ 516,794	$ 587,872	$ 529,219
Net charge-offs to loan average balance	0.00%	0.00%	0.00%	0.00%
Real estate \| Residential real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	$ 5,821	$ 8,294	$ 6,116	$ 9,418
Charge-offs	0	58	75	58
Recoveries	86	8	92	17
Provision	(56)	815	(282)	(318)
Ending Balance	5,851	9,059	5,851	9,059
Average Balance	$ 937,005	$ 929,332	$ 966,363	$ 908,884
Net charge-offs to loan average balance	(0.04%)	0.02%	0.00%	0.01%
Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	$ 36,315	$ 49,342	$ 40,146	$ 51,857
Charge-offs	2,179	2,845	4,325	5,800
Recoveries	545	186	1,180	294
Provision	796	(1,634)	(1,524)	(1,302)
Ending Balance	35,477	45,049	35,477	45,049
Average Balance	$ 1,411,946	$ 1,761,803	$ 1,398,802	$ 1,791,281
Net charge-offs to loan average balance	0.47%	0.61%	0.45%	0.62%
Mortgage warehouse lines of credit
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	$ 329	$ 923	$ 340	$ 856
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	130	(363)	119	(296)
Ending Balance	459	560	459	560
Average Balance	$ 434,381	$ 819,233	$ 444,851	$ 890,127
Net charge-offs to loan average balance	0.00%	0.00%	0.00%	0.00%
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	$ 522	$ 791	$ 548	$ 918
Charge-offs	13	5	28	49
Recoveries	8	5	13	18
Provision	0	(239)	(16)	(335)
Ending Balance	517	552	517	552
Average Balance	$ 16,219	$ 16,632	$ 15,979	$ 17,138
Net charge-offs to loan average balance	0.13%	0.00%	0.19%	0.36%

Credit Loss, Expense (Reversal)

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- Definition

Percentage of writeoff after recovery to average financing receivables outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (4)

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

+ References

No definition available.

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- Definition

Amount of expense (reversal of expense) for expected credit loss on investment in debt security measured at amortized cost (held-to-maturity).

+ References

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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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

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- Definition

Amount of increase in allowance for credit loss on financing receivable from recovery.

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- Definition

Amount of writeoff of financing receivable, charged against allowance for credit loss.

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-Publisher FASB
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- Definition

Average amount outstanding, before allowance for credit loss, of financing receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
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-Number 229
-Section 1402
-Paragraph (a)

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Amount of expense (reversal of expense) for expected credit loss for off-balance sheet credit exposure. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging.

+ References

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Amount of credit loss expense (reversal of expense) for financing receivable.

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