Portfolio Loans - Summary of Allowance for Loan Losses by Portfolio Class and Category (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Nov. 12, 2020
Allowance for Loan Losses [Roll Forward]
Balance, beginning of year	$ 43,288	$ 43,288
Balance, end of year			$ 43,288
Non-Covered Loans
Allowance for Loan Losses [Roll Forward]
Balance, beginning of year	42,567	42,567	42,295	$ 38,166
CECL adoption	28,387
PCD loans immediately charged off	(1,680)	(63,400)	(6,700)
Provision for loan losses		63,379	6,682	9,813
Initial Allowance on Acquired PCD Loans					$ 3,524
Charge-offs		(6,739)	(8,594)	(7,976)
Recoveries		6,512	2,184	2,292
Balance, end of year	69,995	136,671	42,567	42,295
Financing Receivable, Allowance For Credit Losses, Organic			42,567
Financing Receivable, Allowance For Credit Losses, Purchased Credit Impaired			721
Non-Covered Loans | Commercial and industrial
Allowance for Loan Losses [Roll Forward]
Balance, beginning of year	27,296	27,296	29,039	26,406
CECL adoption	6,494
PCD loans immediately charged off	0
Provision for loan losses		28,373	4,801	8,394
Initial Allowance on Acquired PCD Loans					23
Charge-offs		(5,381)	(6,882)	(6,894)
Recoveries		1,848	338	1,133
Balance, end of year	33,949	58,812	27,296	29,039
Financing Receivable, Allowance For Credit Losses, Organic			27,296
Financing Receivable, Allowance For Credit Losses, Purchased Credit Impaired			159
Non-Covered Loans | Commercial - investor owned
Allowance for Loan Losses [Roll Forward]
Balance, beginning of year	5,935	5,935	4,683	3,890
CECL adoption	10,726
PCD loans immediately charged off	(5)
Provision for loan losses		11,037	1,708	709
Initial Allowance on Acquired PCD Loans					2,026
Charge-offs		(498)	(551)	0
Recoveries		2,841	95	84
Balance, end of year	16,656	32,062	5,935	4,683
Financing Receivable, Allowance For Credit Losses, Organic			5,935
Financing Receivable, Allowance For Credit Losses, Purchased Credit Impaired			0
Non-Covered Loans | CRE - owner occupied
Allowance for Loan Losses [Roll Forward]
Balance, beginning of year	4,873	4,873	4,239	3,308
CECL adoption	2,598
PCD loans immediately charged off	(57)
Provision for loan losses		7,845	673	1,216
Initial Allowance on Acquired PCD Loans					1,427
Charge-offs		(30)	(58)	(313)
Recoveries		356	19	28
Balance, end of year	7,414	17,012	4,873	4,239
Financing Receivable, Allowance For Credit Losses, Organic			4,873
Financing Receivable, Allowance For Credit Losses, Purchased Credit Impaired			0
Non-Covered Loans | Construction and land development
Allowance for Loan Losses [Roll Forward]
Balance, beginning of year	2,472	2,472	1,987	1,487
CECL adoption	5,183
PCD loans immediately charged off	(217)
Provision for loan losses		13,438	(237)	97
Initial Allowance on Acquired PCD Loans					45
Charge-offs		(31)	(54)	(56)
Recoveries		384	776	459
Balance, end of year	7,577	21,413	2,472	1,987
Financing Receivable, Allowance For Credit Losses, Organic			2,472
Financing Receivable, Allowance For Credit Losses, Purchased Credit Impaired			139
Non-Covered Loans | Residential real estate
Allowance for Loan Losses [Roll Forward]
Balance, beginning of year	1,280	1,280	1,616	2,237
CECL adoption	3,470
PCD loans immediately charged off	(1,401)
Provision for loan losses		674	(330)	(583)
Initial Allowance on Acquired PCD Loans					3
Charge-offs		(408)	(667)	(546)
Recoveries		967	661	508
Balance, end of year	3,349	4,585	1,280	1,616
Financing Receivable, Allowance For Credit Losses, Organic			1,280
Financing Receivable, Allowance For Credit Losses, Purchased Credit Impaired			0
Non-Covered Loans | Other
Allowance for Loan Losses [Roll Forward]
Balance, beginning of year	711	711	731	838
CECL adoption	(84)
PCD loans immediately charged off	0
Provision for loan losses		2,012	67	(20)
Initial Allowance on Acquired PCD Loans					$ 0
Charge-offs		(391)	(382)	(167)
Recoveries		116	295	80
Balance, end of year	$ 1,050	$ 2,787	711	$ 731
Financing Receivable, Allowance For Credit Losses, Organic			711
Financing Receivable, Allowance For Credit Losses, Purchased Credit Impaired			$ 423