SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts receivable and revenue adjustments
Changes in valuation and qualifying accounts and reserves
Balance at Beginning of Period	$ 7,380	$ 7,657	$ 5,437
Additions, Charged to Costs and Expenses	1,223	2,336	4,081
Additions, Charged to Other Accounts	(245)	863	2,416
Deductions	2,910	3,476	4,277
Balance at End of Period	5,448	7,380	7,657
Allowance for other accounts receivable
Changes in valuation and qualifying accounts and reserves
Balance at Beginning of Period	806	921	849
Additions, Charged to Costs and Expenses	(330)	(115)	72
Balance at End of Period	476	806	921
Allowance for deferred tax assets
Changes in valuation and qualifying accounts and reserves
Balance at Beginning of Period	53	844	293
Deductions	(615)	791	(551)
Balance at End of Period	$ 668	$ 53	$ 844

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of valuation and qualifying accounts and reserves.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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Amount of increase in valuation and qualifying accounts and reserves from charge to cost and expense.

+ References

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Amount of increase in valuation and qualifying accounts and reserves from charge to accounts other than cost and expense.

+ References

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Amount of decrease in valuation and qualifying accounts and reserves.

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