MORTGAGE SERVICING RIGHTS - Balance of loans serviced for others and fair value of mortgage servicing rights (Details) - Balance of loans serviced for others and fair value of mortgage servicing rights - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2014	Dec. 31, 2015
Residential mortgage loans serviced for others	$ 128,141	$ 135,831
Fair value of mortgage servicing rights	$ 961		$ 1,383