SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration of Credit Risk - Revenues (Details)	6 Months Ended
Jun. 30, 2021
Revenue Benchmark \| Customer Concentration Risk \| Wells Fargo Bank, NA
Concentration Risk [Line Items]
Concentration risk (as a percent)	15.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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