Reinsurance - Essent Guaranty's Excess of Loss Reinsurance Coverages and Retentions (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Radnor Re, Total
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	$ 145,201,796
Remaining Risk in Force	39,764,622
Remaining Reinsurance in Force	1,343,737
Remaining First Layer Retention	1,394,042
Radnor Re 2021-1 Ltd. | Reinsurance Policy, Type [Axis]: Vintage Year Aug 2020 - Mar 2021
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	25,750,186
Remaining Risk in Force	6,963,249
Remaining Reinsurance in Force	220,532
Remaining First Layer Retention	277,985
Radnor Re 2021-2 Ltd. | Reinsurance Policy, Type [Axis]: Vintage Year Apr 2021 - Sep 2021
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	31,287,234
Remaining Risk in Force	8,616,211
Remaining Reinsurance in Force	286,439
Remaining First Layer Retention	277,195
Radnor Re 2022-1 Ltd. | Reinsurance Policy, Type [Axis]: Vintage Year Oct 2021 - Jul 2022
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	28,815,017
Remaining Risk in Force	7,856,567
Remaining Reinsurance in Force	191,938
Remaining First Layer Retention	301,278
Radnor Re 2023-1 | Reinsurance Policy, Type [Axis]: Vintage August 2022- June 2023
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	28,989,426
Remaining Risk in Force	7,941,539
Remaining Reinsurance in Force	281,462
Remaining First Layer Retention	281,089
Radnor Re 2024-1 | Reinsurance Policy, Type [Axis]: Vintage July 2023- July 2024
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	30,359,933
Remaining Risk in Force	8,387,056
Remaining Reinsurance in Force	363,366
Remaining First Layer Retention	256,495
OXL, Total
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	146,567,347
Remaining Risk in Force	40,087,087
Remaining Reinsurance in Force	331,892
Remaining First Layer Retention	1,589,460
XOL 2019-1 | Reinsurance Policy, Type [Axis]: Vintage Year Jan 2018 - Dec 2018
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	4,811,623
Remaining Risk in Force	1,266,631
Remaining Reinsurance in Force	76,144
Remaining First Layer Retention	244,294
XOL 2020-1 | Reinsurance Policy, Type [Axis]: Vintage Year Jan 2019 - Aug 2019
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	6,026,073
Remaining Risk in Force	1,591,126
Remaining Reinsurance in Force	30,592
Remaining First Layer Retention	212,208
XOL 2022-1 | Reinsurance Policy, Type [Axis]: Vintage Year Oct 2021 - Dec 2022
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	65,149,106
Remaining Risk in Force	17,727,315
Remaining Reinsurance in Force	141,992
Remaining First Layer Retention	500,886
XOL 2023-1 | Reinsurance Policy, Type [Axis]: Vintage Year Jan 2023 - Dec 2023
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	38,402,550
Remaining Risk in Force	10,637,649
Remaining Reinsurance in Force	36,627
Remaining First Layer Retention	366,141
XOL 2024-1 | Reinsurance Policy, Type [Axis]: Vintage Year Jan 2024 - Dec 2024
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	32,177,995
Remaining Risk in Force	8,864,366
Remaining Reinsurance in Force	46,537
Remaining First Layer Retention	$ 265,931