SUMMARY OF SIGNIFICANT ACCOUNTING AND BUSINESS POLICIES - Receivables and Credit Risk (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 10,126	$ 9,015	$ 8,160
Charged to costs and expenses	139	2,368	3,367
Charged to other accounts	79	(86)	22
Deductions	(1,415)	(1,171)	(2,534)
Balance at end of year	$ 8,929	$ 10,126	$ 9,015