Purchase Credit Impaired ("PCI") Loans - Summary of PCI Loans by Category (Details) - Covered Loans $ in Thousands	Sep. 30, 2015 USD ($) rating	Dec. 31, 2014 USD ($) rating
Covered Loans [Line Items]
Recorded Investment PCI Loans	$ 83,736	$ 99,103
Construction and land development
Covered Loans [Line Items]
Weighted- Average Risk Rating | rating	6.31	6.16
Recorded Investment PCI Loans	$ 7,068	$ 7,740
Commercial Real Estate Investor Owned
Covered Loans [Line Items]
Weighted- Average Risk Rating | rating	7.11	7.07
Recorded Investment PCI Loans	$ 32,534	$ 39,066
CRE - owner occupied
Covered Loans [Line Items]
Weighted- Average Risk Rating | rating	6.35	6.35
Recorded Investment PCI Loans	$ 20,008	$ 22,695
Residential real estate
Covered Loans [Line Items]
Weighted- Average Risk Rating | rating	5.44	5.54
Recorded Investment PCI Loans	$ 20,404	$ 25,121
Total real estate loans
Covered Loans [Line Items]
Recorded Investment PCI Loans	$ 80,014	$ 94,622
Commercial and industrial
Covered Loans [Line Items]
Weighted- Average Risk Rating | rating	6.72	6.57
Recorded Investment PCI Loans	$ 3,467	$ 4,012
Consumer and other
Covered Loans [Line Items]
Weighted- Average Risk Rating | rating	6.13	5.39
Recorded Investment PCI Loans	$ 255	$ 469