Loans - Summary of Recorded Investment in Portfolio Loans by Class and Category Based on Impairment Method (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020 USD ($) loan	Sep. 30, 2020 USD ($) loan	Sep. 30, 2019 USD ($) loan	Jun. 30, 2020 USD ($)	Jan. 01, 2020 USD ($)	Dec. 31, 2019 USD ($)
Summary of Recorded Investment in Non-covered Loans by Portfolio Class and Category Based on Impairment Method [Line Items]
Financing Receivable, Modifications, Number of Contracts | loan	3
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 3,933
Financing Receivable, Troubled Debt Restructuring, Premodification	3,933
Total					$ 43,288
Portfolio loans, net
Summary of Recorded Investment in Non-covered Loans by Portfolio Class and Category Based on Impairment Method [Line Items]
Financing Receivable, Modifications, Number of Contracts | loan		6	3
Financing Receivable, Troubled Debt Restructuring, Postmodification		$ 7,819	$ 520
Financing Receivable, Troubled Debt Restructuring, Premodification		7,819	$ 520
Total	123,270	123,270		$ 110,270	69,995	$ 43,288
Loans - Ending balance:
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	(21,244)	(21,244)				(2,616)
Total	6,147,551	$ 6,147,551				5,316,953
Portfolio loans, net | Commercial and industrial
Summary of Recorded Investment in Non-covered Loans by Portfolio Class and Category Based on Impairment Method [Line Items]
Financing Receivable, Modifications, Number of Contracts | loan		3	0
Financing Receivable, Troubled Debt Restructuring, Postmodification		$ 7,447	$ 0
Financing Receivable, Troubled Debt Restructuring, Premodification		7,447	$ 0
Total	57,870	57,870		50,139	33,949	27,455
Loans - Ending balance:
Total	3,171,916	3,171,916				2,361,157
Portfolio loans, net | CRE - investor owned
Summary of Recorded Investment in Non-covered Loans by Portfolio Class and Category Based on Impairment Method [Line Items]
Total	29,671	29,671		25,019	16,656	5,935
Loans - Ending balance:
Total	1,292,182	$ 1,292,182				1,299,884
Portfolio loans, net | CRE - owner occupied
Summary of Recorded Investment in Non-covered Loans by Portfolio Class and Category Based on Impairment Method [Line Items]
Financing Receivable, Modifications, Number of Contracts | loan		0	1
Financing Receivable, Troubled Debt Restructuring, Postmodification		$ 0	$ 188
Financing Receivable, Troubled Debt Restructuring, Premodification		0	$ 188
Total	9,472	9,472		11,088	7,414	4,873
Loans - Ending balance:
Total	735,704	735,704				697,437
Portfolio loans, net | Construction and land development
Summary of Recorded Investment in Non-covered Loans by Portfolio Class and Category Based on Impairment Method [Line Items]
Total	18,918	18,918		15,962	7,577	2,611
Loans - Ending balance:
Total	474,727	$ 474,727				457,273
Portfolio loans, net | Residential real estate
Summary of Recorded Investment in Non-covered Loans by Portfolio Class and Category Based on Impairment Method [Line Items]
Financing Receivable, Modifications, Number of Contracts | loan		3	2
Financing Receivable, Troubled Debt Restructuring, Postmodification		$ 372	$ 332
Financing Receivable, Troubled Debt Restructuring, Premodification		372	$ 332
Total	5,331	5,331		6,333	3,349	1,280
Loans - Ending balance:
Total	321,792	321,792				366,261
Portfolio loans, net | Other
Summary of Recorded Investment in Non-covered Loans by Portfolio Class and Category Based on Impairment Method [Line Items]
Total	2,008	2,008		$ 1,729	$ 1,050	1,134
Loans - Ending balance:
Total	$ 151,230	$ 151,230				$ 134,941