Marketable Investment Securities, Restricted Cash and Cash Equivalents, and Other Investment Securities - Changes in Level 3 Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair values transfers between Level 1 and Level 2
Fair value assets transfer from level 1 to level 2	$ 0
Fair value liabilities transfer from level 1 to level 2		$ 0
Fair value assets transfer from level 2 to level 1	$ 0
Fair value liabilities transfer from level 2 to level 1		$ 0

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bb)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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- Definition

Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

+ References

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- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

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- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

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- References

No definition available.

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