LOANS AND ALLOWANCE FOR LOAN LOSSES - INFORMATION ON IMPAIRED LOANS (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 5,254,780	$ 3,077,656
Non-PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	12,317	15,553
Related Allowance	234	487
Unpaid Principal Balance	17,885	15,734
Non-PCI Loans | Recorded Investment With a Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	2,006	3,278
Non-PCI Loans | Recorded Investment With no Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	10,311	12,275
Non-PCI Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	7,461	8,449
Related Allowance	154	314
Unpaid Principal Balance	7,187	8,515
Non-PCI Loans | Commercial real estate | Recorded Investment With a Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	988	1,262
Non-PCI Loans | Commercial real estate | Recorded Investment With no Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	6,473	7,187
Non-PCI Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	3,015	2,623
Related Allowance	41	106
Unpaid Principal Balance	9,064	2,695
Non-PCI Loans | Commercial and industrial | Recorded Investment With a Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	130	531
Non-PCI Loans | Commercial and industrial | Recorded Investment With no Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	2,885	2,092
Non-PCI Loans | Construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	370	177
Related Allowance	5	0
Unpaid Principal Balance	175	180
Non-PCI Loans | Construction and development | Recorded Investment With a Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Non-PCI Loans | Construction and development | Recorded Investment With no Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	370	177
Non-PCI Loans | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	888	3,550
Related Allowance	34	0
Unpaid Principal Balance	888	3,568
Non-PCI Loans | Residential real estate | Recorded Investment With a Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	888	1,465
Non-PCI Loans | Residential real estate | Recorded Investment With no Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	2,085
Non-PCI Loans | Construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		417
Related Allowance		0
Unpaid Principal Balance		417
Non-PCI Loans | Construction and development | Recorded Investment With a Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		0
Non-PCI Loans | Construction and development | Recorded Investment With no Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		417
Non-PCI Loans | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	583	337
Related Allowance	0	67
Unpaid Principal Balance	571	359
Non-PCI Loans | Home equity | Recorded Investment With a Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	20
Non-PCI Loans | Home equity | Recorded Investment With no Recorded Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 583	$ 317