LOANS AND ALLOWANCE FOR LOAN LOSSES (Loans Stated at Face Amount, Net of Deferred Fees and Costs) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Loans and Leases Receivable Disclosure [Line Items]
Total loans held for investment, net	$ 6,898,729	$ 6,307,060	$ 6,148,918
Loans receivable, deferred fees and costs	335	1,800
Construction and Land Development
Loans and Leases Receivable Disclosure [Line Items]
Total loans held for investment, net	841,738	751,131	776,430
Commercial Real Estate - Owner Occupied
Loans and Leases Receivable Disclosure [Line Items]
Total loans held for investment, net	903,523	857,805	857,142
Commercial Real Estate - Non-Owner Occupied
Loans and Leases Receivable Disclosure [Line Items]
Total loans held for investment, net	1,748,039	1,564,295	1,454,828
Multifamily Real Estate
Loans and Leases Receivable Disclosure [Line Items]
Total loans held for investment, net	368,686	334,276	339,313
Commercial & Industrial
Loans and Leases Receivable Disclosure [Line Items]
Total loans held for investment, net	554,522	551,526	509,857
Residential 1-4 Family
Loans and Leases Receivable Disclosure [Line Items]
Total loans held for investment, net	1,083,112	1,029,547	999,361
Auto
Loans and Leases Receivable Disclosure [Line Items]
Total loans held for investment, net	276,572	262,071	255,188
HELOC
Loans and Leases Receivable Disclosure [Line Items]
Total loans held for investment, net	535,446	526,884	524,097
Consumer and all other
Loans and Leases Receivable Disclosure [Line Items]
Total loans held for investment, net	$ 587,091	$ 429,525	$ 432,702