CONVERTIBLE SENIOR NOTES AND CALL OPTIONS - Call options (Details) - 12 months ended Dec. 31, 2019 - Call Option [Member] $ in Millions	CNY (¥)	USD ($)
Debt Instrument [Line Items]
Derivative Asset, Fair Value, Gross Asset \| $		$ 30
Fair Value, Option, Changes in Fair Value, Gain (Loss)	¥ 84,891,634
Exchange Gain for Call Option	¥ 2,709,000

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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