SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance Beginning of Period	$ 16,173	$ 15,046	$ 15,194
Additions Charged to Operating Expense	15,817	7,901	6,907
Deductions from Reserves	5,622	6,774	7,055
Balance End of Period	26,368	16,173	15,046
Revenue Allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance Beginning of Period	11,626	14,203	16,232
Additions Charged to Operating Expense	41,338	24,862	24,252
Deductions from Reserves	35,017	27,439	26,281
Balance End of Period	17,947	11,626	14,203
Valuation Allowance on Deferred Tax Assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance Beginning of Period	68,355	55,189	30,916
Additions Charged to Operating Expense	10,466	9,052	22,564
Deductions from Reserves	474	4,114	1,709
Balance End of Period	$ 79,295	$ 68,355	$ 55,189