FAIR VALUE - Summary of Carrying Value and Fair Value of Company's Financial Instruments (Details) - USD ($) $ in Thousands		Sep. 30, 2015		Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity		$ 209,047		$ 207,904
Loans, net		2,080,119		1,804,814
Quoted Prices in Active Markets for Identical Assets Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity	[1]	0		0
Loans, net		0	[1]	0
Deposit liabilities		0		0
Borrowings		0		0
Subordinated debt		0		0
Significant Other Observable Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity	[1]	212,362		208,788
Loans, net		0	[1]	0
Deposit liabilities		0		0
Borrowings		52,387		53,584
Subordinated debt		59,169		53,861
Significant Unobservable Inputs Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity	[1]	0		0
Loans, net		2,085,632	[1]	1,814,746
Deposit liabilities		2,742,915		2,417,355
Borrowings		0		0
Subordinated debt		0		0
Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity	[1]	209,047		207,904
Loans, net		2,071,893	[1]	1,794,405
Deposit liabilities		2,742,296		2,416,534
Borrowings		50,000		50,000
Subordinated debt		$ 69,891		$ 64,583

[1] See Note D for further detail of fair value of individual investment categories.