Loans - Schedule of Portfolio Loans, Purchased Credit Impaired Loans and Purchased Unimpaired Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	$ 3,974,016	$ 3,817,377
Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	618,870	606,014
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	190,836	189,436
Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	359,070	343,125
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	1,701,295	1,639,992
Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	1,103,945	1,038,810
Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	3,221,569	2,922,609
Portfolio Loans | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	548,758	512,430
Portfolio Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	183,718	178,826
Portfolio Loans | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	250,314	215,315
Portfolio Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	1,297,051	1,170,618
Portfolio Loans | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	941,728	845,420
PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	13,215	17,417
PCI Loans | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	794	894
PCI Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	0	0
PCI Loans | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	126	1,121
PCI Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	10,878	9,776
PCI Loans | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	1,417	5,626
PULs
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	739,232	877,351
PULs | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	69,318	92,690
PULs | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	7,118	10,610
PULs | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	108,630	126,689
PULs | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	393,366	459,598
PULs | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Totals	160,800	187,764
PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred costs	$ 15,000	$ 12,900