FAIR VALUE MEASUREMENTS - Changes in Level 3 fair value of available-for-sale securities (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
FAIR VALUE MEASUREMENTS
Balance at January 1,	¥ 150,922	¥ 104,134
Addition	48,659	57,000	¥ 85,000
Change in fair value	38,883	(10,212)	19,134
Balance at December 31,	¥ 238,464	¥ 150,922	¥ 104,134

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

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