Reinsurance - Essent Guaranty's Excess of Loss Reinsurance Coverages and Retentions (Details) $ in Thousands	9 Months Ended
Sep. 30, 2026 USD ($)
Radnor Re, Total
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	$ 85,542,550
Remaining Risk in Force	23,962,286
Remaining Reinsurance in Force	602,979
Remaining First Layer Retention	1,054,396
OXL, Total
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	187,130,701
Remaining Risk in Force	51,144,331
Remaining Reinsurance in Force	391,086
Remaining First Layer Retention	1,959,947
Reinsurance Policy, Type [Axis]: Vintage Year Apr 2021 - Sep 2021 \| Radnor Re 2021-2 Ltd.
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	20,877,708
Remaining Risk in Force	5,977,329
Remaining Reinsurance in Force	148,357
Remaining First Layer Retention	266,363
Reinsurance Policy, Type [Axis]: Vintage Year August 2022- June 2023 \| Radnor Re 2023-1 Ltd.
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	22,010,726
Remaining Risk in Force	6,079,835
Remaining Reinsurance in Force	171,531
Remaining First Layer Retention	258,439
Reinsurance Policy, Type [Axis]: Vintage Year Jan 2019 - Aug 2019 \| XOL 2020-1
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	3,931,249
Remaining Risk in Force	1,049,217
Remaining Reinsurance in Force	29,152
Remaining First Layer Retention	209,436
Reinsurance Policy, Type [Axis]: Vintage Year Jan 2023 - Dec 2023 \| XOL 2023-1
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	27,740,342
Remaining Risk in Force	7,730,197
Remaining Reinsurance in Force	29,762
Remaining First Layer Retention	343,895
Reinsurance Policy, Type [Axis]: Vintage Year Jan 2024 - Dec 2024 \| XOL 2024-1
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	31,121,953
Remaining Risk in Force	8,588,331
Remaining Reinsurance in Force	58,005
Remaining First Layer Retention	324,933
Reinsurance Policy, Type [Axis]: Vintage Year Jan 2025 - Dec 2025 \| XOL 2025-1
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	39,061,433
Remaining Risk in Force	10,378,090
Remaining Reinsurance in Force	80,821
Remaining First Layer Retention	342,687
Reinsurance Policy, Type [Axis]: Vintage Year Jan 2026 - Dec 2026 \| XOL 2026-1
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	35,992,643
Remaining Risk in Force	9,683,655
Remaining Reinsurance in Force	67,786
Remaining First Layer Retention	292,776
Reinsurance Policy, Type [Axis]: Vintage Year July 2023- July 2024 \| Radnor Re 2024-1 Ltd.
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	21,023,421
Remaining Risk in Force	5,835,276
Remaining Reinsurance in Force	179,151
Remaining First Layer Retention	248,378
Reinsurance Policy, Type [Axis]: Vintage Year Oct 2021 - Dec 2022 \| XOL 2022-1
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	49,283,081
Remaining Risk in Force	13,714,841
Remaining Reinsurance in Force	125,560
Remaining First Layer Retention	446,220
Reinsurance Policy, Type [Axis]: Vintage Year Oct 2021 - Jul 2022 \| Radnor Re 2022-1 Ltd.
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Remaining Insurance in Force	21,630,695
Remaining Risk in Force	6,069,846
Remaining Reinsurance in Force	103,940
Remaining First Layer Retention	$ 281,216