SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts
Movement in valuation and qualifying accounts
Balance at Beginning of Period	$ 6,563	$ 3,914	$ 4,611
Charged to Costs and Expenses	2,670	3,009	3,109
Deductions	(618)	(360)	(3,806)
Balance at End of Period	8,615	6,563	3,914
Reserve for sales returns
Movement in valuation and qualifying accounts
Balance at Beginning of Period	2,802	3,099	3,370
Charged to Costs and Expenses	48,160	53,202	57,356
Deductions	(48,609)	(53,499)	(57,627)
Balance at End of Period	2,353	2,802	3,099
Tax valuation allowances
Movement in valuation and qualifying accounts
Balance at Beginning of Period	20,025	17,479	21,324
Charged to Costs and Expenses	27,117	2,546	0
Deductions	(4,794)	0	(3,845)
Balance at End of Period	$ 42,348	$ 20,025	$ 17,479