Loans - Schedule of Portfolio Loans, Purchased Credit Impaired Loans and Purchased Unimpaired Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	$ 4,828,441	$ 4,825,214
Deferred costs	17,800	16,900
Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	417,565	443,568
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	2,162,417	2,132,066
Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	1,329,166	1,324,377
Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	712,879	722,322
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	206,414	202,881
Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	3,667,222	3,588,251
Portfolio Loans | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	308,846	301,473
Portfolio Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	1,478,955	1,437,989
Portfolio Loans | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	1,077,523	1,055,525
Portfolio Loans | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	606,179	603,057
Portfolio Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	195,719	190,207
PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	13,788	14,434
PCI Loans | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	153	151
PCI Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	10,393	10,828
PCI Loans | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	2,575	2,718
PCI Loans | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	667	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	1,147,431	1,222,529
PULs | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	108,566	141,944
PULs | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	673,069	683,249
PULs | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	249,068	266,134
PULs | Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	106,033	118,528
PULs | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	$ 10,695	$ 12,674