LOANS AND ALLOWANCE FOR LOAN LOSSES (Loans Receivables Related Risk Rating Including Purchased Impaired Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	$ 6,148,918	$ 5,671,462	$ 5,543,621
Construction and Land Development
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	776,430	749,720	694,645
Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	857,142	860,086	863,578
Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	1,454,828	1,270,480	1,223,607
Multifamily Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	339,313	322,528	329,959
Commercial & Industrial
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	509,857	435,365	409,657
Residential 1-4 Family
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	999,361	978,469	987,788
HELOC
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	524,097	516,726	514,362
Consumer and all other
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	432,702	304,027	294,031
Purchased Impaired
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	62,346	73,737	78,606
Purchased Impaired | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	21,053	22,339
Purchased Impaired | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	29,968	33,862
Purchased Impaired | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	10,384	15,760
Purchased Impaired | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	941	1,776
Purchased Impaired | Construction and Land Development
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	3,205	5,986	7,628
Purchased Impaired | Construction and Land Development | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	1,102	2,059
Purchased Impaired | Construction and Land Development | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	1,677	1,778
Purchased Impaired | Construction and Land Development | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	426	1,908
Purchased Impaired | Construction and Land Development | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	0	241
Purchased Impaired | Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	19,064	27,388	28,694
Purchased Impaired | Commercial Real Estate - Owner Occupied | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	5,313	5,260
Purchased Impaired | Commercial Real Estate - Owner Occupied | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	9,036	15,530
Purchased Impaired | Commercial Real Estate - Owner Occupied | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	4,715	6,598
Purchased Impaired | Commercial Real Estate - Owner Occupied | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	0	0
Purchased Impaired | Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	18,141	13,519	13,326
Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	4,855	4,442
Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	11,562	7,827
Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	1,724	1,250
Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	0	0
Purchased Impaired | Multifamily Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	2,079	1,555	1,943
Purchased Impaired | Multifamily Real Estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	347	356
Purchased Impaired | Multifamily Real Estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	1,732	1,199
Purchased Impaired | Multifamily Real Estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	0	0
Purchased Impaired | Multifamily Real Estate | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	0	0
Purchased Impaired | Commercial & Industrial
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	1,145	1,813	2,245
Purchased Impaired | Commercial & Industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	93	144
Purchased Impaired | Commercial & Industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	496	359
Purchased Impaired | Commercial & Industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	556	1,289
Purchased Impaired | Commercial & Industrial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	0	21
Purchased Impaired | Residential 1-4 Family
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	16,828	21,159	22,379
Purchased Impaired | Residential 1-4 Family | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	8,085	9,098
Purchased Impaired | Residential 1-4 Family | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	5,297	6,380
Purchased Impaired | Residential 1-4 Family | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	2,941	4,605
Purchased Impaired | Residential 1-4 Family | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	505	1,076
Purchased Impaired | HELOC
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	1,498	1,791	1,812
Purchased Impaired | HELOC | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	932	923
Purchased Impaired | HELOC | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	130	410
Purchased Impaired | HELOC | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	0	20
Purchased Impaired | HELOC | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	436	438
Purchased Impaired | Consumer and all other
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	386	526	$ 579
Purchased Impaired | Consumer and all other | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	326	57
Purchased Impaired | Consumer and all other | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	38	379
Purchased Impaired | Consumer and all other | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	22	90
Purchased Impaired | Consumer and all other | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment, net of deferred fees and costs	$ 0	$ 0