Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Allowance for Loan and Lease Losses and Corresponding Loan and Lease Balances (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Allowance for loan and lease losses
Beginning balance	$ 51,300	$ 31,132	$ 31,936	$ 25,201
Provisions	15,740	5,931	45,713	16,321
Charge-offs	(6,145)	(5,686)	(17,615)	(11,314)
Recoveries	363	208	1,224	1,377
Ending balance	61,258	31,585	61,258	31,585
Ending balance:
Individually evaluated for impairment					$ 14,782		$ 9,562
Collectively evaluated for impairment					41,445		19,221
Allowance for loan and lease losses	51,300	31,585	31,936	25,201	61,258	$ 31,936	31,585
Loans and leases ending balance:
Individually evaluated for impairment					77,890		53,176
Collectively evaluated for impairment					4,079,809		3,502,892
Total loans and leases					4,374,517	3,785,661	3,831,090
Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					5,031		2,802
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					216,818		275,022
Commercial Real Estate
Allowance for loan and lease losses
Beginning balance	14,110	8,934	7,965	7,540
Provisions	6,421	1,075	14,149	4,212
Charge-offs	(1,566)	(1,459)	(3,206)	(3,628)
Recoveries	19	3	76	429
Ending balance	18,984	8,553	18,984	8,553
Ending balance:
Individually evaluated for impairment					4,516		2,728
Collectively evaluated for impairment					11,825		4,458
Allowance for loan and lease losses	18,984	8,553	7,965	7,540	18,984	7,965	8,553
Loans and leases ending balance:
Individually evaluated for impairment					39,001		24,071
Collectively evaluated for impairment					1,191,740		1,139,782
Total loans and leases					1,347,855	1,276,542	1,306,288
Commercial Real Estate | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					2,643		1,367
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					117,114		142,435
Residential Real Estate
Allowance for loan and lease losses
Beginning balance	3,741	2,171	1,990	1,751
Provisions	291	74	2,031	230
Charge-offs	(250)		(259)	(9)
Recoveries	8	6	28	279
Ending balance	3,790	2,251	3,790	2,251
Ending balance:
Individually evaluated for impairment					77		39
Collectively evaluated for impairment					3,413		1,612
Allowance for loan and lease losses	3,790	2,251	1,990	1,751	3,790	1,990	2,251
Loans and leases ending balance:
Individually evaluated for impairment					1,636		2,374
Collectively evaluated for impairment					547,563		637,320
Total loans and leases					633,396	711,822	749,103
Residential Real Estate | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					300		600
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					84,197		109,409
Construction, Land Development, and Other Land
Allowance for loan and lease losses
Beginning balance	1,491	691	610	466
Provisions	1,029	125	1,910	350
Charge-offs	(701)		(701)
Recoveries	53		53
Ending balance	1,872	816	1,872	816
Ending balance:
Collectively evaluated for impairment					1,685		802
Allowance for loan and lease losses	1,872	816	610	466	1,872	610	816
Loans and leases ending balance:
Collectively evaluated for impairment					234,230		276,437
Total loans and leases					239,034	278,657	280,999
Construction, Land Development, and Other Land | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					187		14
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					4,804		4,562
Commercial and Industrial
Allowance for loan and lease losses
Beginning balance	30,108	17,126	19,377	12,932
Provisions	7,603	4,198	26,844	10,550
Charge-offs	(3,254)	(3,561)	(12,057)	(5,740)
Recoveries	83	20	376	41
Ending balance	34,540	17,783	34,540	17,783
Ending balance:
Individually evaluated for impairment					10,189		6,795
Collectively evaluated for impairment					22,450		10,169
Allowance for loan and lease losses	34,540	17,783	19,377	12,932	34,540	19,377	17,783
Loans and leases ending balance:
Individually evaluated for impairment					37,253		26,731
Collectively evaluated for impairment					1,281,067		1,257,082
Total loans and leases					1,328,809	1,331,565	1,302,162
Commercial and Industrial | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					1,901		819
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					10,489		18,349
Paycheck Protection Program ("PPP")
Loans and leases ending balance:
Collectively evaluated for impairment					622,191
Total loans and leases					622,191
Installment and Other
Allowance for loan and lease losses
Beginning balance	36	67	50	49
Provisions	1	(12)	(13)	10
Charge-offs		(1)		(5)
Recoveries		1		1
Ending balance	37	55	37	55
Ending balance:
Collectively evaluated for impairment					37		53
Allowance for loan and lease losses	37	55	50	49	37	50	55
Loans and leases ending balance:
Collectively evaluated for impairment					2,929		9,087
Total loans and leases					3,143	6,565	9,354
Installment and Other | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality							2
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					214		267
Lease Financing Receivables
Allowance for loan and lease losses
Beginning balance	1,814	2,143	1,944	2,463
Provisions	395	471	792	969
Charge-offs	(374)	(665)	(1,392)	(1,932)
Recoveries	200	178	691	627
Ending balance	2,035	2,127	2,035	2,127
Ending balance:
Collectively evaluated for impairment					2,035		2,127
Allowance for loan and lease losses	$ 2,035	$ 2,127	$ 1,944	$ 2,463	2,035	1,944	2,127
Loans and leases ending balance:
Collectively evaluated for impairment					200,089		183,184
Total loans and leases					$ 200,089	$ 180,510	$ 183,184