Basis of Presentation and Update to Accounting Policy (Policies)	3 Months Ended
Mar. 31, 2020
Basis of Presentation and Update to Accounting Policy [Abstract]
Allowance for Credit Losses	Allowance for Credit LossesWe closely monitor accounts receivable and held to maturity investment balances and estimate the allowance for credit losses. Our estimate is based on historical collection experience, external market data and other factors, including those related to current market conditions and events. Our credit losses associated with accounts receivable and held to maturity investments have not historically been material.

Disclosure of accounting policy for determining the allowance for doubtful accounts for trade and other accounts receivable balances, and when impairments, charge-offs or recoveries are recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84158767&loc=d3e18780-107790

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(4))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5144-111524

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