SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Other Income, Net Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Income, Net [Line Items]
Other Income, Net	$ 21,184	$ 13,641	$ 56,304	$ 23,689
Equity Method Investments
Other Income, Net [Line Items]
Other Income, Net	$ 5,100	$ 900	$ 23,000	$ (2,000)