BASIS OF PRESENTATION - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in other assets	$ (293,875)		$ (293,875)		$ (308,544)
Decrease in settlement expenses	(1,258,824)	$ (1,171,034)	(3,735,160)	$ (3,147,641)
Decrease in other policyholders' funds	(1,715,231)		(1,715,231)		(1,576,856)
Decrease in deferred policy acquisition costs	(54,855,476)		(54,855,476)		$ (54,738,794)
Increase in amortization of deferred policy acquisition costs	109,141	61,350	144,596	125,560
Decrease in ceded premiums	(52,457)	(59,692)	(170,994)	(168,566)
Decrease in other ceded operating expenses	(192,650)	(193,801)	(572,871)	(574,432)
Increase in income before income taxes	72,612	$ 239,841	369,926	$ 602,291
Revision of Prior Period, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in settlement expenses	18,100
Decrease in deferred policy acquisition costs	18,100		18,100
Increase in amortization of deferred policy acquisition costs	6,100
Decrease in ceded premiums	10,200
Decrease in other ceded operating expenses	3,200
Increase in income before income taxes	$ 19,000		$ 9,400