RELATED PARTY TRANSACTIONS - Loans to related parties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Summary of loans to related parties
Balance at beginning of year	$ 142,516	$ 136,514
New loans	108,698	81,302
Repayments	(45,446)	(75,300)
Balance at end of year	$ 205,768	$ 142,516