ACCOUNTING POLICIES - Fixed Assets, Depreciation Expense, Intangible Assets and Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment	$ 26,262	$ 26,411	$ 28,848
Intangible assets other than goodwill
Total intangible assets, gross	30,284	29,099
Accumulated amortization of intangible assets	(18,528)	(15,729)
Total intangible assets, net	11,756	13,370
Amortization of intangible assets	4,769	5,286	3,999
Amortization Of Intangible Assets Including Impact Of Purchase Price Allocation Adjustments	$ 3,332	5,286	3,999
Weighted average remaining useful life for intangible assets	5 years 6 months 17 days
Cost of goods sold — retail
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment	$ 687	354	307
Technology [Member]
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment	20,798	21,894	24,604
Intangible assets other than goodwill
Amortization of intangible assets	3,726	3,424	3,620
Sales and marketing
Intangible assets other than goodwill
Amortization of intangible assets	64	460	83
General and administrative
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment	4,777	4,163	3,937
Intangible assets other than goodwill
Amortization of intangible assets	$ (458)	$ 1,402	$ 296
Building
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years
Land improvements
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Building machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Building machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Furniture and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Furniture and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Computer hardware | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Computer hardware | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	4 years
Computer software | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	2 years
Computer software | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	4 years