ACCOUNTING POLICIES ACCOUNTING POLICIES - Allowance for Sales Returns Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Allowance for returns, beginning of period	$ 15,261	$ 17,391	$ 18,176
Additions to the allowance	117,040	174,864	169,398
Deductions from the allowance	(121,194)	(176,994)	(170,183)
Allowance for returns, end of period	$ 11,107	$ 15,261	$ 17,391