SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Derivative Instruments (Details)	3 Months Ended	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) quarter	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Minimum
Derivative [Line Items]
Period between issuance of a loan commitment and closing and sale of the loan		30 days
Maximum
Derivative [Line Items]
Period between issuance of a loan commitment and closing and sale of the loan		120 days
Mortgage Banking
Derivative [Line Items]
One-time expense from revision in accounting estimate	$ 706,000
Level III
Derivative [Line Items]
Interest rate lock commitments	1,546,000	$ 1,546,000	$ 1,537,000	$ 1,020,000
Interest Rate Cap
Derivative [Line Items]
Notional amount	$ 100,000,000	$ 100,000,000
Rate protection transaction term		5 years
Number of quarterly caps | quarter		20
Fixed cost		$ 1,500,000
LIBOR | Interest Rate Cap
Derivative [Line Items]
Description of variable rate basis		3 month LIBOR
Strike price	3.00%	3.00%
Forward Sales Commitments
Derivative [Line Items]
Derivative liability	$ 0	$ 0	0
Carrying Value | Interest Rate Cap
Derivative [Line Items]
Derivative asset	268,000	268,000	437,000
Carrying Value | Interest Rate Swap
Derivative [Line Items]
Derivative liability	250,000	250,000	405,000
Derivative asset	$ 250,000	$ 250,000	$ 405,000