Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Contractual Delinquency Information (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	$ 3,831,090	$ 3,501,626	$ 3,455,802
Commercial Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	1,306,288	1,261,607	1,272,204
Residential Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	749,103	704,902	705,196
Construction, Land Development, and Other Land
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	280,999	185,349	181,705
Commercial and Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	1,302,162	1,144,797	1,095,446
Installment and Other
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	9,354	13,718	12,194
Lease Financing Receivables
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	183,184	191,253	$ 189,057
Acquired Non-Impaired and Originated Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	63,730	50,297
Non-accrual	39,528	25,834
Current	3,492,338	3,173,787
Total loans and leases	3,556,068	3,224,084
Acquired Non-Impaired and Originated Loans | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	16,571	19,697
Acquired Non-Impaired and Originated Loans | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	7,631	4,766
Acquired Non-Impaired and Originated Loans | Commercial Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	20,775	18,288
Non-accrual	12,186	9,484
Current	1,143,078	1,096,511
Total loans and leases	1,163,853	1,114,799
Acquired Non-Impaired and Originated Loans | Commercial Real Estate | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	6,140	6,659
Acquired Non-Impaired and Originated Loans | Commercial Real Estate | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	2,449	2,145
Acquired Non-Impaired and Originated Loans | Residential Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	3,225	7,014
Non-accrual	2,092	1,815
Current	636,469	583,954
Total loans and leases	639,694	590,968
Acquired Non-Impaired and Originated Loans | Residential Real Estate | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	632	4,488
Acquired Non-Impaired and Originated Loans | Residential Real Estate | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	501	711
Acquired Non-Impaired and Originated Loans | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	3,203
Current	273,234	181,570
Total loans and leases	276,437	181,570
Acquired Non-Impaired and Originated Loans | Construction, Land Development, and Other Land | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	3,203
Acquired Non-Impaired and Originated Loans | Commercial and Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	34,746	21,137
Non-accrual	24,592	13,932
Current	1,249,067	1,111,043
Total loans and leases	1,283,813	1,132,180
Acquired Non-Impaired and Originated Loans | Commercial and Industrial | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	9,136	5,829
Acquired Non-Impaired and Originated Loans | Commercial and Industrial | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,018	1,376
Acquired Non-Impaired and Originated Loans | Installment and Other
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	13	1,948
Non-accrual	1	12
Current	9,074	11,366
Total loans and leases	9,087	13,314
Acquired Non-Impaired and Originated Loans | Installment and Other | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	12	1,932
Acquired Non-Impaired and Originated Loans | Installment and Other | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		4
Acquired Non-Impaired and Originated Loans | Lease Financing Receivables
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,768	1,910
Non-accrual	657	591
Current	181,416	189,343
Total loans and leases	183,184	191,253
Acquired Non-Impaired and Originated Loans | Lease Financing Receivables | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	651	789
Acquired Non-Impaired and Originated Loans | Lease Financing Receivables | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	$ 460	$ 530