Loans - Summary of Portfolio Loans by Category (Details) - Portfolio loans, net - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	$ 6,147,551	$ 5,316,953
Unearned loan fees, net	(21,244)	(2,616)
Loans, including unearned loan fees	6,126,307	5,314,337
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	3,171,916	2,361,157
Loans, including unearned loan fees	3,152,394
Commercial - investor owned
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	1,292,182	1,299,884
Loans, including unearned loan fees	1,292,182
Commercial - owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	735,704	697,437
Loans, including unearned loan fees	735,704
Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	474,727	457,273
Loans, including unearned loan fees	474,727
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	321,792	366,261
Loans, including unearned loan fees	321,792
Total real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	2,824,405	2,820,855
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, before unearned loan fees	151,230	$ 134,941
Loans, including unearned loan fees	$ 149,508

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Amount, after fee received for commitment to originate or purchase, of financing receivable. Excludes financing receivable covered under loss sharing agreement.

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Amount, before allowance for credit loss, of financing receivable.

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Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

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