SIGNIFICANT ACCOUNTING POLICIES - Revenue recognition - Deferred Customer Acquisition Costs (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
SIGNIFICANT ACCOUNTING POLICIES
Capitalized Contract Cost, Amortization Period	1 year 9 months 18 days
Capitalized Contract Cost, Impairment Loss	$ 0	$ 0
Opening balance	11,366	8,976
Additions to deferred customer acquisition costs	6,378	2,628
Amortization of deferred customer acquisition costs	(5,933)	(2,089)
Ending balance	$ 11,811	$ 9,515