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 and revenue reserves
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	$ 9,263	$ 9,177	$ 8,171
Charges to Earnings	47,242	27,514	17,425
Charges to Other Accounts	(506)	271	(56)
Deductions	(39,396)	(27,699)	(16,363)
Balance at End of Period	16,603	9,263	9,177
Deferred tax valuation allowance
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	61,563	14,180	12,696
Charges to Earnings	(599)	42,310	2,384
Charges to Other Accounts	(2,061)	5,073	(900)
Deductions	0	0	0
Balance at End of Period	58,903	61,563	$ 14,180
Other reserves
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	0
Balance at End of Period	$ 3,919	$ 0