Loans - Schedule of Portfolio Loans, Purchased Credit Impaired Loans and Purchased Unimpaired Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	$ 4,059,323	$ 3,817,377
PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred costs	15,900	12,900
Real Estate | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	376,257	343,125
Real Estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	1,726,699	1,639,992
Real Estate | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	1,152,640	1,038,810
Commercial and financial | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	610,955	606,014
Consumer | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	192,772	189,436
Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	3,383,571	2,922,609
Portfolio Loans | Real Estate | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	289,449	215,315
Portfolio Loans | Real Estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	1,357,721	1,170,618
Portfolio Loans | Real Estate | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	994,575	845,420
Portfolio Loans | Commercial and financial | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	554,627	512,430
Portfolio Loans | Consumer | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	187,199	178,826
PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	13,051	17,417
PCI Loans | Real Estate | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	129	1,121
PCI Loans | Real Estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	10,838	9,776
PCI Loans | Real Estate | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	1,356	5,626
PCI Loans | Commercial and financial | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	728	894
PCI Loans | Consumer | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	0	0
PULs
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	662,701	877,351
PULs | Real Estate | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	86,679	126,689
PULs | Real Estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	358,140	459,598
PULs | Real Estate | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	156,709	187,764
PULs | Commercial and financial | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	55,600	92,690
PULs | Consumer | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	$ 5,573	$ 10,610