SEGMENTS INFORMATION - Major Customers (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)
Revenue, Major Customer [Line Items]
Revenues	$ 298,293	$ 236,049	$ 846,607	$ 653,875
Operating Segments
Revenue, Major Customer [Line Items]
Revenues	298,354	236,174	847,145	654,437
Operating Segments | Europe
Revenue, Major Customer [Line Items]
Revenues	$ 126,265	$ 103,514	$ 349,834	$ 292,826
Sales Revenue, Net | Customer Concentration Risk | Operating Segments | Europe | UBS AG
Revenue, Major Customer [Line Items]
Number of customers	1	1	1	1
Revenues	$ 35,142	$ 32,960	$ 107,381	$ 95,826
Accounts Receivable | Customer Concentration Risk | Unbilled Revenues
Revenue, Major Customer [Line Items]
Number of customers			1
Accounts Receivable | Customer Concentration Risk | UBS AG | Billed Revenues
Revenue, Major Customer [Line Items]
Concentration percentage			10.30%
Accounts Receivable | Customer Concentration Risk | UBS AG | Unbilled Revenues
Revenue, Major Customer [Line Items]
Concentration percentage			10.70%