DEBT AND CREDIT FACILITIES - Schedule of Debt Obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2025	May 01, 2025	Apr. 01, 2025	Mar. 05, 2025	Feb. 25, 2025	Dec. 31, 2024	May 04, 2015	Mar. 24, 2015
Debt Instrument [Line Items]
Long-term debt	$ 2,300,000					$ 1,900,000
Fair Value
Debt Instrument [Line Items]
Long-term debt	2,309,308					1,871,492
Carrying Value
Debt Instrument [Line Items]
Long-term debt	2,229,135					1,886,689
Senior Notes \| Fair Value
Debt Instrument [Line Items]
Long-term debt	2,309,308					1,871,492
Senior Notes \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	2,229,135					1,886,689
Line of Credit \| Medici Revolving Credit Facility \| Fair Value \| Revolving Credit Facility
Debt Instrument [Line Items]
Long-term debt	0					0
Line of Credit \| Medici Revolving Credit Facility \| Carrying Value \| Revolving Credit Facility
Debt Instrument [Line Items]
Long-term debt	$ 0					0
5.950% Senior Notes due 2035 (DaVinci) \| Senior Notes \| DaVinciRe Holdings Ltd.
Debt Instrument [Line Items]
Stated interest rate	5.95%			5.95%
5.950% Senior Notes due 2035 (DaVinci) \| Senior Notes \| DaVinciRe Holdings Ltd. \| Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 308,643					0
5.950% Senior Notes due 2035 (DaVinci) \| Senior Notes \| DaVinciRe Holdings Ltd. \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 296,890					0
5.800% Senior Notes due 2035 \| Senior Notes
Debt Instrument [Line Items]
Stated interest rate	5.80%				5.80%
5.800% Senior Notes due 2035 \| Senior Notes \| Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 524,145					0
5.800% Senior Notes due 2035 \| Senior Notes \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 493,601					0
5.750% Senior Notes due 2033 \| Senior Notes
Debt Instrument [Line Items]
Stated interest rate	5.75%
5.750% Senior Notes due 2033 \| Senior Notes \| Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 788,295					755,693
5.750% Senior Notes due 2033 \| Senior Notes \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 742,772					742,068
3.600% Senior Notes due 2029 \| Senior Notes
Debt Instrument [Line Items]
Stated interest rate	3.60%
3.600% Senior Notes due 2029 \| Senior Notes \| Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 391,456					376,816
3.600% Senior Notes due 2029 \| Senior Notes \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 396,737					396,051
3.450% Senior Notes due 2027 \| Senior Notes \| RenaissanceRe Finance, Inc.
Debt Instrument [Line Items]
Stated interest rate	3.45%
3.450% Senior Notes due 2027 \| Senior Notes \| RenaissanceRe Finance, Inc. \| Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 296,769					290,070
3.450% Senior Notes due 2027 \| Senior Notes \| RenaissanceRe Finance, Inc. \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 299,135					298,765
3.700% Senior Notes due 2025 \| Senior Notes \| RenaissanceRe Finance, Inc.
Debt Instrument [Line Items]
Stated interest rate	3.70%		3.70%					3.70%
3.700% Senior Notes due 2025 \| Senior Notes \| RenaissanceRe Finance, Inc. \| Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 0					299,550
3.700% Senior Notes due 2025 \| Senior Notes \| RenaissanceRe Finance, Inc. \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 0					299,908
4.750% Senior Notes due 2025 (DaVinci) \| Senior Notes \| DaVinciRe Holdings Ltd.
Debt Instrument [Line Items]
Stated interest rate	4.75%	4.75%		4.75%			4.75%
4.750% Senior Notes due 2025 (DaVinci) \| Senior Notes \| DaVinciRe Holdings Ltd. \| Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 0					149,363
4.750% Senior Notes due 2025 (DaVinci) \| Senior Notes \| DaVinciRe Holdings Ltd. \| Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 0					$ 149,897