Loans - Summary of Loans by Rating Category (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Fair value of acquired performing loans at acquisition		$ 147,300
Loans	$ 3,580,966	3,302,264
Acquired Performing Impaired Loans
Financing Receivable, Recorded Investment [Line Items]
Fair value of acquired performing loans at acquisition		145,843
Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	811,199	784,737
SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	141,208	149,779
Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	248,317	238,910
Indirect automobile
Financing Receivable, Recorded Investment [Line Items]
Loans	1,716,156	1,575,865
Installment
Financing Receivable, Recorded Investment [Line Items]
Loans	25,995	33,225
Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	489,721	386,582
Home equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Loans	148,370	133,166
Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,755,848	1,613,018
Pass | Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	758,271	721,133
Pass | SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	129,629	131,047
Pass | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	235,987	229,978
Pass | Indirect automobile
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Pass | Installment
Financing Receivable, Recorded Investment [Line Items]
Loans	25,229	32,521
Pass | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	461,650	368,492
Pass | Home equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Loans	145,082	129,847
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	36,041	46,006
Special Mention | Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	21,264	31,040
Special Mention | SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	6,847	10,997
Special Mention | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	7,699	615
Special Mention | Indirect automobile
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Special Mention | Installment
Financing Receivable, Recorded Investment [Line Items]
Loans	231	45
Special Mention | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	0	2,759
Special Mention | Home equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Loans	0	550
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	77,893	71,378
Substandard | Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	31,664	32,564
Substandard | SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	4,732	7,735
Substandard | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	4,631	8,317
Substandard | Indirect automobile
Financing Receivable, Recorded Investment [Line Items]
Loans	4,972	4,003
Substandard | Installment
Financing Receivable, Recorded Investment [Line Items]
Loans	535	659
Substandard | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	28,071	15,331
Substandard | Home equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Loans	3,288	2,769
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Doubtful | Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Doubtful | SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Doubtful | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Doubtful | Indirect automobile
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Doubtful | Installment
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Doubtful | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Doubtful | Home equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Loss
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Loss | Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Loss | SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Loss | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Loss | Indirect automobile
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Loss | Installment
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Loss | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Loss | Home equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Graded Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	1,869,782	1,730,402
Graded Loans | Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	811,199	784,737
Graded Loans | SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	141,208	149,779
Graded Loans | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	248,317	238,910
Graded Loans | Indirect automobile
Financing Receivable, Recorded Investment [Line Items]
Loans	4,972	4,003
Graded Loans | Installment
Financing Receivable, Recorded Investment [Line Items]
Loans	25,995	33,225
Graded Loans | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	489,721	386,582
Graded Loans | Home equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Loans	148,370	133,166
Ungraded Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	1,711,184	1,571,862
Ungraded Performing | Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Ungraded Performing | SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Ungraded Performing | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Ungraded Performing | Indirect automobile
Financing Receivable, Recorded Investment [Line Items]
Loans	1,711,184	1,571,862
Ungraded Performing | Installment
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Ungraded Performing | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Ungraded Performing | Home equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 0	$ 0