SECURITIES - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) security	Dec. 31, 2016 USD ($) security	Dec. 31, 2015 USD ($)
Securities Pledged
Sale of available for sale securities	$ 349,374,000	$ 0	$ 109,444,000
Net gain (loss) on sale of available-for-sale securities	(38,000)	$ 0	772,000
Gross realized gains	910,000
Gross realized losses	$ 948,000
Average loss on securities, percent	1.69%	1.04%
Number of securities in an unrealized loss position | security	18	9
Amortized cost of securities	$ 55,700,000	$ 73,000,000
Fair value of pledged securities	55,500,000	72,600,000
Repurchase Agreements
Securities Pledged
Amortized cost of securities pledged	6,300,000	12,200,000
Securities pledged and available to be sold under repurchase agreements, fair value	6,300,000	12,200,000
Deposits
Securities Pledged
Amortized cost of securities pledged		1,300,000
Securities pledged and available to be sold under repurchase agreements, fair value		1,300,000
Derivative
Securities Pledged
Amortized cost of securities pledged	3,400,000	5,200,000
Securities pledged and available to be sold under repurchase agreements, fair value	$ 3,300,000	$ 5,200,000
Patriot Bancshares Inc
Securities Pledged
Sale of available for sale securities			76,500,000
Net gain (loss) on sale of available-for-sale securities			195,000
Gross realized gains			225,000
Gross realized losses			$ 30,000