SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) primary_source	Dec. 31, 2020 USD ($) input_method	Dec. 31, 2019 USD ($)	Jan. 01, 2019 USD ($)
Valuation of investment securities
Number of primary sources of information used for determining fair value | primary_source	1
Total number of primary sources of information available for determining fair value	3	3
Cash
Negative balances due to outstanding checks and drafts	$ 184.7	$ 184.7	$ 183.7
Deferred Policy Acquisition Costs
Right-of-use asset				$ 18.2
Lease liability				$ 18.2
Operating Lease, Liability, Statement of Financial Position [Extensible List]				Other liabilities
Minimum
Deferred Policy Acquisition Costs
Interest rate assumptions to compute liabilities for future policy benefits	1.00%	1.00%
Maximum
Deferred Policy Acquisition Costs
Interest rate assumptions to compute liabilities for future policy benefits	6.85%	6.85%