Summarized Information on Location and Gross Amount of Derivatives on Consolidated Balance Sheets (Detail) - Not Designated as Hedging Instrument - Other Assets Liabilities - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Notional Amount	[1]	$ 213,022	$ 242,018
Fair Value	[1]	(8,395)	(16,430)
Interest Rate Swap
Derivatives, Fair Value [Line Items]
Notional Amount		213,022	213,022
Fair Value		(8,395)	(16,430)
Futures Contracts on Bonds
Derivatives, Fair Value [Line Items]
Notional Amount	[2]	0	28,996
Fair Value	[2]	$ 0	$ 0

[1] The derivatives are held by GBLI Holdings, LLC and are guaranteed by Global Indemnity Group, LLC

[2] Futures are settled daily such that their fair value is not reflected in the consolidated statements of financial position