Allowance for Credit Losses - Activity in Allowance for Loan Losses (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jan. 01, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	$ 35,154	$ 85,411	$ 32,822	$ 35,154	$ 32,423
Initial Allowance on PCD Loans Acquired During the Period				516
Provision for Credit Losses		7,611	2,551	37,124	3,948
Charge- Offs		(2,495)	(2,644)	(4,141)	(4,123)
Recoveries		744	803	1,417	1,319
TDR Allowance Adjustments		(21)	(27)	(46)	(62)
Ending Balance		91,250	33,505	$ 91,250	33,505
Accounting Standards Update [Extensible List]				us-gaap:AccountingStandardsUpdate201613Member
Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	1,842	4,646	2,320	$ 1,842	2,233
Initial Allowance on PCD Loans Acquired During the Period				48
Provision for Credit Losses		2,478	(79)	3,727	4
Charge- Offs		0	(1)	0	0
Recoveries		37	3	66	7
TDR Allowance Adjustments		0	0	(1)	(1)
Ending Balance		7,161	2,243	7,161	2,243
Commercial real estate - owner-occupied
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	5,361	5,327		5,361
Initial Allowance on PCD Loans Acquired During the Period				207
Provision for Credit Losses		229		(34)
Charge- Offs		0		(45)
Recoveries		18		18
TDR Allowance Adjustments		(12)		(25)
Ending Balance		5,562		5,562
Commercial real estate - non owner-occupied
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	7,863	35,643		7,863
Initial Allowance on PCD Loans Acquired During the Period				140
Provision for Credit Losses		3,345		21,628
Charge- Offs		0		(12)
Recoveries		4		32
TDR Allowance Adjustments		0		0
Ending Balance		38,992		38,992
Commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	13,224		11,753	13,224	11,112
Provision for Credit Losses			(433)		192
Charge- Offs			0		(16)
Recoveries			565		612
TDR Allowance Adjustments			(15)		(30)
Ending Balance			11,870		11,870
Residential real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	7,667	19,899	7,445	7,667	7,775
Initial Allowance on PCD Loans Acquired During the Period				97
Provision for Credit Losses		574	51	6,834	(363)
Charge- Offs		(113)	(28)	(131)	(65)
Recoveries		101	51	218	190
TDR Allowance Adjustments		(8)	(11)	(19)	(29)
Ending Balance		20,453	7,508	20,453	7,508
Commercial and financial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	9,716	15,470	8,573	9,716	8,585
Initial Allowance on PCD Loans Acquired During the Period				11
Provision for Credit Losses		1,319	2,114	4,063	2,967
Charge- Offs		(1,768)	(1,881)	(2,866)	(2,825)
Recoveries		493	106	913	185
TDR Allowance Adjustments		0	0	0	0
Ending Balance		15,514	8,912	15,514	8,912
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	2,705	4,426	2,731	2,705	2,718
Initial Allowance on PCD Loans Acquired During the Period				13
Provision for Credit Losses		(334)	898	906	1,148
Charge- Offs		(614)	(734)	(1,087)	(1,217)
Recoveries		91	78	170	325
TDR Allowance Adjustments		(1)	(1)	(1)	(2)
Ending Balance		3,568	$ 2,972	3,568	$ 2,972
Paycheck Protection Program
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	0	0		0
Initial Allowance on PCD Loans Acquired During the Period				0
Provision for Credit Losses		0		0
Charge- Offs		0		0
Recoveries		0		0
TDR Allowance Adjustments		0		0
Ending Balance		$ 0		0
Cumulative Effect Adjustment
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	21,226			21,226
Initial Allowance on PCD Loans Acquired During the Period	700
Ending Balance	21,226
Cumulative Effect Adjustment | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	1,479			1,479
Cumulative Effect Adjustment | Commercial real estate - owner-occupied
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	80			80
Cumulative Effect Adjustment | Commercial real estate - non owner-occupied
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	9,341			9,341
Cumulative Effect Adjustment | Residential real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	5,787			5,787
Cumulative Effect Adjustment | Commercial and financial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	3,677			3,677
Cumulative Effect Adjustment | Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	862			862
Cumulative Effect Adjustment | Paycheck Protection Program
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	$ 0			$ 0