COMMITMENTS AND CONTINGENCIES - Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
COMMITMENTS AND CONTINGENCIES
Net revenues generated from these kindergartens	$ 156,498	$ 140,803	$ 108,513
VIE's Kindergartens
COMMITMENTS AND CONTINGENCIES
Net revenues generated from these kindergartens	$ 11,685	$ 7,241	$ 4,489

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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