REINSURANCE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Premiums written
Gross	$ 7,685,984	$ 6,826,938	$ 6,898,858
Ceded	(2,759,360)	(2,490,529)	(2,409,243)
Net	4,926,624	4,336,409	4,489,615
Premiums earned
Gross	7,281,709	6,768,733	6,910,677
Ceded	(2,571,859)	(2,397,424)	(2,323,499)
Net	4,709,850	4,371,309	4,587,178
Reinsurance receivables:
Ceded losses and loss expenses	1,782,000	1,914,000	1,602,000
Allowance for credit losses on reinsurance recoverable for unpaid losses and loss expenses	$ 29,554	$ 23,711	$ 18,000