CONTINGENCIES, COMMITMENTS, AND GUARANTEES - SO Litigation (Details) - Pending Litigation - lawsuit			12 Months Ended
	May 04, 2018	Apr. 25, 2018	Dec. 31, 2017	Aug. 31, 2017
Putative Securities Class Action
Loss Contingencies [Line Items]
Class action complaint, increase in purported class period			1 day
Shareholder Derivative Lawsuits
Loss Contingencies [Line Items]
Number of claims				2
Stay period	30 days	30 days