SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND PRACTICES - New Accounting Standards - Condensed Consolidated Financial Statements - Without Adoption of ASU 2014-09 (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
ASSETS
Prepaid expenses and other current assets	$ 30,418		$ 30,418		$ 17,950
LIABILITIES AND EQUITY
Retained earnings	73,901		73,901		$ 115,780
Statement of Operations [Abstract]
Revenues	343,889	$ 312,256	646,274	$ 598,810
Operating expenses	246,707	227,613	473,558	439,363
Provision for income taxes	(2,977)	4	(2,354)	(6,075)
Net loss	(32,470)	$ (11,086)	(50,315)	$ (20,594)
Without adoption of ASC 606 | ASU 2014-09
ASSETS
Prepaid expenses and other current assets	18,009		18,009
LIABILITIES AND EQUITY
Retained earnings	61,492		61,492
Statement of Operations [Abstract]
Revenues	344,356		641,213
Operating expenses	246,310		472,112
Provision for income taxes	(2,439)		(1,995)
Net loss	$ (32,144)		$ (54,289)