SIGNIFICANT ACCOUNTING POLICIES AND RECENT ACCOUNTING STANDARDS - Concentrations of Risk (Details)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Concentration Risk [Line Items]
Financial institutions agreement, notice period	90 days
Minimum
Concentration Risk [Line Items]
Financial institutions agreement, term	3 years
Maximum
Concentration Risk [Line Items]
Financial institutions agreement, term	5 years
One Customer | Customer Concentration Risk | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk	10.00%	7.00%
United States | Largest FI Partner | Supplier Concentration Risk | Financial Institution Partner
Concentration Risk [Line Items]
Concentration risk	68.00%	63.00%
United Kingdom | Largest FI Partner | Supplier Concentration Risk | Financial Institution Partner
Concentration Risk [Line Items]
Concentration risk	9.00%	11.00%