TAXATION - Valuation allowance (Details)	12 Months Ended
Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)
TAXATION
Beginning Balance	$ 49,148,842	¥ 342,164,400		¥ 401,743,718
Decrease in valuation allowance	(3,005,481)	(20,923,558)	$ 3,000,000	(59,579,318)	¥ 59,600,000
Ending Balance	$ 46,143,361	¥ 321,240,842	$ 49,148,842	¥ 342,164,400	¥ 401,743,718

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319

Name:	us-gaap_DeferredTaxAssetsValuationAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant