COMMITMENTS AND CONTINGENCIES - Surety Bonds (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
COMMITMENTS AND CONTINGENCIES
Outstanding surety bonds	$ 4.8	$ 4.8
Percentage of annual fees on surety bonds	1.50%
Percentage of upfront deposit on surety bonds	10.00%
Surety bonds upfront deposit amount	$ 0.5