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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Allowance for loan and lease losses
Beginning balance	$ 31,132	$ 19,687	$ 25,201	$ 16,706
Provisions	5,931	5,842	16,321	14,913
Charge-offs	(5,686)	(2,421)	(11,314)	(9,228)
Recoveries	208	316	1,377	1,033
Ending balance	31,585	23,424	31,585	23,424
Ending balance:
Individually evaluated for impairment					$ 9,562		$ 6,422
Collectively evaluated for impairment					19,221		14,007
Allowance for loan and lease losses	31,585	19,687	31,585	23,424	31,585	$ 25,201	23,424
Loans and leases ending balance:
Individually evaluated for impairment					53,176		35,529
Collectively evaluated for impairment					3,502,892		3,126,105
Total loans and leases					3,831,090	3,501,626	3,455,802
Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					2,802		2,995
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					275,022		294,168
Commercial Real Estate
Allowance for loan and lease losses
Beginning balance	8,934	6,453	7,540	4,794
Provisions	1,075	1,705	4,212	3,975
Charge-offs	(1,459)	(736)	(3,628)	(1,347)
Recoveries	3		429
Ending balance	8,553	7,422	8,553	7,422
Ending balance:
Individually evaluated for impairment					2,728		2,294
Collectively evaluated for impairment					4,458		3,413
Allowance for loan and lease losses	8,934	6,453	8,553	7,422	8,553	7,540	7,422
Loans and leases ending balance:
Individually evaluated for impairment					24,071		13,612
Collectively evaluated for impairment					1,139,782		1,104,484
Total loans and leases					1,306,288	1,261,607	1,272,204
Commercial Real Estate | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					1,367		1,715
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					142,435		154,108
Residential Real Estate
Allowance for loan and lease losses
Beginning balance	2,171	1,648	1,751	1,638
Provisions	74	29	230	39
Charge-offs			(9)
Recoveries	6		279
Ending balance	2,251	1,677	2,251	1,677
Ending balance:
Individually evaluated for impairment					39		70
Collectively evaluated for impairment					1,612		1,150
Allowance for loan and lease losses	2,171	1,648	2,251	1,677	2,251	1,751	1,677
Loans and leases ending balance:
Individually evaluated for impairment					2,374		1,941
Collectively evaluated for impairment					637,320		582,292
Total loans and leases					749,103	704,902	705,196
Residential Real Estate | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					600		457
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					109,409		120,963
Construction, Land Development, and Other Land
Allowance for loan and lease losses
Beginning balance	691	332	466	222
Provisions	125	58	350	586
Charge-offs				(418)
Ending balance	816	390	816	390
Ending balance:
Collectively evaluated for impairment					802		390
Allowance for loan and lease losses	691	332	816	390	816	466	390
Loans and leases ending balance:
Collectively evaluated for impairment					276,437		177,502
Total loans and leases					280,999	185,349	181,705
Construction, Land Development, and Other Land | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					14
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					4,562		4,203
Commercial and Industrial
Allowance for loan and lease losses
Beginning balance	17,126	8,369	12,932	7,418
Provisions	4,198	3,579	10,550	8,959
Charge-offs	(3,561)	(858)	(5,740)	(5,539)
Recoveries	20	75	41	327
Ending balance	17,783	11,165	17,783	11,165
Ending balance:
Individually evaluated for impairment					6,795		4,044
Collectively evaluated for impairment					10,169		6,301
Allowance for loan and lease losses	17,126	8,369	17,783	11,165	17,783	12,932	11,165
Loans and leases ending balance:
Individually evaluated for impairment					26,731		19,962
Collectively evaluated for impairment					1,257,082		1,061,048
Total loans and leases					1,302,162	1,144,797	1,095,446
Commercial and Industrial | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					819		820
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					18,349		14,436
Installment and Other
Allowance for loan and lease losses
Beginning balance	67	30	49	41
Provisions	(12)	12	10	33
Charge-offs	(1)	(4)	(5)	(36)
Recoveries	1		1
Ending balance	55	38	55	38
Ending balance:
Individually evaluated for impairment							14
Collectively evaluated for impairment					53		21
Allowance for loan and lease losses	67	30	55	38	55	49	38
Loans and leases ending balance:
Individually evaluated for impairment							14
Collectively evaluated for impairment					9,087		11,722
Total loans and leases					9,354	13,718	12,194
Installment and Other | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					2		3
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					267		458
Lease Financing Receivables
Allowance for loan and lease losses
Beginning balance	2,143	2,855	2,463	2,593
Provisions	471	459	969	1,321
Charge-offs	(665)	(823)	(1,932)	(1,888)
Recoveries	178	241	627	706
Ending balance	2,127	2,732	2,127	2,732
Ending balance:
Collectively evaluated for impairment					2,127		2,732
Allowance for loan and lease losses	$ 2,143	$ 2,855	$ 2,127	$ 2,732	2,127	2,463	2,732
Loans and leases ending balance:
Collectively evaluated for impairment					183,184		189,057
Total loans and leases					$ 183,184	$ 191,253	$ 189,057