SEGMENTS INFORMATION - Revenues from External Customers and Operating Profit/(Loss) Before Unallocated Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Revenues	$ 324,651	$ 264,482
Operating profit	30,966	30,331
Russia
Segment Reporting Information [Line Items]
Revenues	13,209	8,965
Operating Segments
Segment Reporting Information [Line Items]
Revenues	324,703	264,814
Operating profit	60,452	48,647
Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	178,303	147,490
Operating profit	37,092	30,655
Operating Segments | Europe
Segment Reporting Information [Line Items]
Revenues	132,707	107,843
Operating profit	19,811	16,832
Operating Segments | Russia
Segment Reporting Information [Line Items]
Revenues	13,693	9,481
Operating profit	$ 3,549	$ 1,160