Loans - Summary of Portfolio Loans Individually Evaluated for Impairment by Category (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Jan. 01, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Impaired [Line Items]
Financing receivable, allowance for credit loss	$ 43,288
Portfolio loans, net
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance		$ 16,605		$ 16,605
Total Recorded Investment		39,623		39,623			$ 26,425
Financing Receivable, Allowance for Credit Loss, Writeoff		(2,584)		(6,552)
Financing Receivable, Allowance for Credit Loss, Recovery		1,557		5,714
Financing receivable, allowance for credit loss	69,995	123,270		123,270		$ 110,270	43,288
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	28,387
Provision for credit losses	1,680	(14,000)	$ (1,800)	(54,100)	$ (5,000)
Portfolio loans, net | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance		10,208		10,208
Total Recorded Investment		23,586		23,586			22,578
Financing Receivable, Allowance for Credit Loss, Writeoff		(2,006)		(5,372)
Financing Receivable, Allowance for Credit Loss, Recovery		808		1,605
Financing receivable, allowance for credit loss	33,949	57,870		57,870		50,139	27,455
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	6,494
Provision for credit losses	0
Portfolio loans, net | Commercial - investor owned
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance		1,440		1,440
Total Recorded Investment		9,850		9,850			2,303
Financing Receivable, Allowance for Credit Loss, Writeoff		(272)		(498)
Financing Receivable, Allowance for Credit Loss, Recovery		55		2,821
Financing receivable, allowance for credit loss	16,656	29,671		29,671		25,019	5,935
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	10,726
Provision for credit losses	5
Portfolio loans, net | Commercial - owner occupied
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance		1,511		1,511
Total Recorded Investment		1,511		1,511			213
Financing Receivable, Allowance for Credit Loss, Writeoff		(30)		(30)
Financing Receivable, Allowance for Credit Loss, Recovery		268		348
Financing receivable, allowance for credit loss	7,414	9,472		9,472		11,088	4,873
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	2,598
Provision for credit losses	57
Portfolio loans, net | Construction and land development
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance		200		200
Total Recorded Investment		200		200
Financing Receivable, Allowance for Credit Loss, Writeoff		0		(31)
Financing Receivable, Allowance for Credit Loss, Recovery		83		152
Financing receivable, allowance for credit loss	7,577	18,918		18,918		15,962	2,611
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	5,183
Provision for credit losses	217
Portfolio loans, net | Residential real estate
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance		3,246		3,246
Total Recorded Investment		4,394		4,394			1,330
Financing Receivable, Allowance for Credit Loss, Writeoff		(173)		(327)
Financing Receivable, Allowance for Credit Loss, Recovery		303		686
Financing receivable, allowance for credit loss	3,349	5,331		5,331		6,333	1,280
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	3,470
Provision for credit losses	1,401
Portfolio loans, net | Other
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance		0		0
Total Recorded Investment		82		82			1
Financing Receivable, Allowance for Credit Loss, Writeoff		(103)		(294)
Financing Receivable, Allowance for Credit Loss, Recovery		40		102
Financing receivable, allowance for credit loss	1,050	$ 2,008		$ 2,008		$ 1,729	$ 1,134
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	(84)
Provision for credit losses	$ 0