Loans - Summary of Allowance for Loan Losses by Portfolio Class and Category (Details) - USD ($) $ in Thousands		3 Months Ended
	Jan. 01, 2020	Mar. 31, 2020	Mar. 31, 2019
Allowance for Loan Losses [Roll Forward]
Balance	$ 43,288
Portfolio loans, net
Allowance for Loan Losses [Roll Forward]
Balance at December 31, 2019	43,288	$ 43,288
Provision for credit losses	(1,680)	21,695	$ 1,500
Charge-offs		(304)
Recoveries		801
Balance	69,995	92,187
Portfolio loans, net | Commercial and industrial
Allowance for Loan Losses [Roll Forward]
Balance at December 31, 2019	27,455	27,455
Provision for credit losses	0	11,591
Charge-offs		(63)
Recoveries		504
Balance	33,949	45,981
Portfolio loans, net | CRE - investor owned
Allowance for Loan Losses [Roll Forward]
Balance at December 31, 2019	5,935	5,935
Provision for credit losses	(5)	3,224
Charge-offs		(2)
Recoveries		14
Balance	16,656	19,892
Portfolio loans, net | CRE - owner occupied
Allowance for Loan Losses [Roll Forward]
Balance at December 31, 2019	4,873	4,873
Provision for credit losses	(57)	1,994
Charge-offs		0
Recoveries		69
Balance	7,414	9,477
Portfolio loans, net | Construction and land development
Allowance for Loan Losses [Roll Forward]
Balance at December 31, 2019	2,611	2,611
Provision for credit losses	(217)	2,309
Charge-offs		(31)
Recoveries		40
Balance	7,577	9,895
Portfolio loans, net | Residential real estate
Allowance for Loan Losses [Roll Forward]
Balance at December 31, 2019	1,280	1,280
Provision for credit losses	(1,401)	2,011
Charge-offs		(122)
Recoveries		157
Balance	3,349	5,395
Portfolio loans, net | Consumer and other
Allowance for Loan Losses [Roll Forward]
Balance at December 31, 2019	1,134	1,134
Provision for credit losses	0	566
Charge-offs		(86)
Recoveries		17
Balance	$ 1,050	$ 1,547