SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recently Issued Accounting Pronouncements (Details) - USD ($) $ in Thousands |
9 Months Ended | |
---|---|---|
Sep. 30, 2018 |
Sep. 30, 2017 |
|
New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||
Net cash provided (used) by operating activities | $ (5,240,047) | $ (2,584,214) |
Net cash provided (used) by investing activities | $ (43,324) | (71,890) |
ASU 2016-18 | ||
New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||
Net cash provided (used) by operating activities | (365,500) | |
Net cash provided (used) by investing activities | $ (168,000) |