Loans - Schedule of Portfolio Loans, Purchased Credit Impaired Loans and Purchased Unimpaired Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	$ 4,986,289	$ 4,825,214
Deferred costs	18,700	16,900
Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	326,324	443,568
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	2,310,367	2,132,066
Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	1,409,946	1,324,377
Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	722,286	722,322
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	217,366	202,881
Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	4,010,299	3,588,251
Portfolio Loans | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	272,915	301,473
Portfolio Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	1,709,227	1,437,989
Portfolio Loans | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	1,184,579	1,055,525
Portfolio Loans | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	635,153	603,057
Portfolio Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	208,425	190,207
PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	13,381	14,434
PCI Loans | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	158	151
PCI Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	10,259	10,828
PCI Loans | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	2,364	2,718
PCI Loans | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	600	737
PCI Loans | 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	962,609	1,222,529
PULs | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	53,251	141,944
PULs | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	590,881	683,249
PULs | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	223,003	266,134
PULs | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	86,533	118,528
PULs | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	$ 8,941	$ 12,674