ACCOUNTING POLICIES ACCOUNTING POLICIES - Allowance for Sales Returns Rollforward (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Allowance for returns	$ 7,897	$ 15,261	$ 17,391
Revenue Recognition, Sales Returns, Reserve for Sales Returns	87,620	174,864
Deductions From Sales Returns, Current	$ (94,984)	$ (176,994)

Amount of estimated sales returns.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84158767&loc=d3e18780-107790

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