Purchased Credit Impaired ("PCI") Loans - Summary of PCI Loans by Category (Details) - Covered Loans $ in Thousands	Jun. 30, 2019 USD ($) rating	Dec. 31, 2018 USD ($) rating
Covered Loans [Line Items]
Recorded Investment PCI Loans	$ 103,315	$ 46,401
Construction and land development
Covered Loans [Line Items]
Weighted- Average Risk Rating1 | rating	5.74	6.03
Recorded Investment PCI Loans	$ 8,187	$ 4,548
CRE - investor owned
Covered Loans [Line Items]
Weighted- Average Risk Rating1 | rating	6.94	7.19
Recorded Investment PCI Loans	$ 41,988	$ 23,939
CRE - owner occupied
Covered Loans [Line Items]
Weighted- Average Risk Rating1 | rating	6.68	7.39
Recorded Investment PCI Loans	$ 22,616	$ 9,669
Residential real estate
Covered Loans [Line Items]
Weighted- Average Risk Rating1 | rating	6.29	6.40
Recorded Investment PCI Loans	$ 13,372	$ 6,082
real estate financing receivable [Domain]
Covered Loans [Line Items]
Recorded Investment PCI Loans	$ 86,163	$ 44,238
Commercial and industrial
Covered Loans [Line Items]
Weighted- Average Risk Rating1 | rating	5.80	6.09
Recorded Investment PCI Loans	$ 16,909	$ 2,159
Consumer and other
Covered Loans [Line Items]
Weighted- Average Risk Rating1 | rating	5.11	2.18
Recorded Investment PCI Loans	$ 243	$ 4