DEFERRED POLICY ACQUISITION COSTS AND VALUE OF BUSINESS ACQUIRED (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Balances and changes in DAC
Balance, beginning of period	$ 837,785	$ 572,328
Capitalization of commissions, sales, and issue expenses	446,468	333,250
Amortization	(133,337)	(52,559)
Change due to unrealized investment gains and losses	56,153	(15,234)
Implementation of ASU 2014-09	138,434	0
Balance, end of period	1,345,503	837,785
Balances and changes in VOBA
Balance, beginning of period	1,361,792	1,447,501
Acquisitions	336,862	0
Amortization	(92,471)	(25,662)
Change due to unrealized investment gains and losses	71,468	(60,047)
Balance, end of period	1,677,651	$ 1,361,792
Expected amortization of VOBA for the next five years
2019	139,662
2020	128,465
2021	114,081
2022	104,147
2023	$ 94,740