Schedule of Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net cash provided by operating activities		$ 45,930	$ 45,871
Cash flows from investing activities:
Proceeds from sale of fixed maturities		642,049	229,362
Proceeds from sale of equity securities		206,212	28,141
Proceeds from maturity of fixed maturities		113,480	43,303
Proceeds from other invested assets		14,201	8,352
Amount received (paid) in connection with derivatives		(12,516)	7,599
Purchases of fixed maturities		(701,684)	(329,002)
Purchases of equity securities		(325,972)	(22,931)
Purchases of other invested assets		(3,500)	(15,800)
Acquisition of business		0	(3,515)
Net cash used for investing activities		(67,730)	(54,491)
Cash flows from financing activities:
Net borrowings (repayments) under margin borrowing facility		8,561	(12,825)
Proceeds / (issuance) of notes to affiliates			0
Debt restructuring			0
Dividends paid to shareholders		(7,130)	(10,510)
Dividends from subsidiaries			0
Purchase of A ordinary shares		(947)	(1,813)
Net cash provided by (used for) financing activities		484	(25,148)
Net change in cash and cash equivalents		(21,316)	(33,768)
Cash and cash equivalents at beginning of period		99,497	74,414
Cash and cash equivalents at end of period		78,181	40,646
Global Indemnity Limited (Parent co-obligor) | Reportable Legal Entities
Cash flows from operating activities:
Net cash provided by operating activities		1,718	(19,280)
Cash flows from investing activities:
Proceeds from sale of fixed maturities		48,393	28,118
Proceeds from sale of equity securities		7,300	0
Proceeds from maturity of fixed maturities		0	5,431
Proceeds from other invested assets		3,161	0
Amount received (paid) in connection with derivatives		0	0
Purchases of fixed maturities		(10,548)	(32,933)
Purchases of equity securities		(40,564)	0
Purchases of other invested assets		0	0
Acquisition of business			0
Net cash used for investing activities		7,742	616
Cash flows from financing activities:
Net borrowings (repayments) under margin borrowing facility		0	0
Proceeds / (issuance) of notes to affiliates			230,000
Debt restructuring			(230,000)
Dividends paid to shareholders		(7,130)	(10,510)
Dividends from subsidiaries			20,000
Purchase of A ordinary shares		(947)	(1,813)
Net cash provided by (used for) financing activities		(8,077)	7,677
Net change in cash and cash equivalents		1,383	(10,987)
Cash and cash equivalents at beginning of period		2,221	11,089
Cash and cash equivalents at end of period		3,604	102
Global Indemnity Group, Inc.(Subsidiary co-obligor) | Reportable Legal Entities
Cash flows from operating activities:
Net cash provided by operating activities		2,593	(618)
Cash flows from investing activities:
Proceeds from sale of fixed maturities		101,525	44,760
Proceeds from sale of equity securities		198,912	28,141
Proceeds from maturity of fixed maturities		0	7,600
Proceeds from other invested assets		11,040	1,058
Amount received (paid) in connection with derivatives		(12,516)	7,599
Purchases of fixed maturities		(24,280)	(39,314)
Purchases of equity securities		(285,408)	(22,931)
Purchases of other invested assets		(3,500)	(15,800)
Acquisition of business			(3,515)
Net cash used for investing activities		(14,227)	7,598
Cash flows from financing activities:
Net borrowings (repayments) under margin borrowing facility		8,561	(12,825)
Proceeds / (issuance) of notes to affiliates			(230,000)
Debt restructuring			230,000
Dividends paid to shareholders		0	0
Dividends from subsidiaries			0
Purchase of A ordinary shares		0	0
Net cash provided by (used for) financing activities		8,561	(12,825)
Net change in cash and cash equivalents		(3,073)	(5,845)
Cash and cash equivalents at beginning of period		26,039	7,749
Cash and cash equivalents at end of period		22,966	1,904
Other Global Indemnity Limited Subsidiaries and Eliminations (non-co-obligor subsidiaries)
Cash flows from operating activities:
Net cash provided by operating activities	[1]	41,619	65,769
Cash flows from investing activities:
Proceeds from sale of fixed maturities	[1]	492,131	156,484
Proceeds from sale of equity securities	[1]	0	0
Proceeds from maturity of fixed maturities	[1]	113,480	30,272
Proceeds from other invested assets	[1]	0	7,294
Amount received (paid) in connection with derivatives	[1]	0	0
Purchases of fixed maturities	[1]	(666,856)	(256,755)
Purchases of equity securities	[1]	0	0
Purchases of other invested assets	[1]	0	0
Acquisition of business	[1]		0
Net cash used for investing activities	[1]	(61,245)	(62,705)
Cash flows from financing activities:
Net borrowings (repayments) under margin borrowing facility	[1]	0	0
Proceeds / (issuance) of notes to affiliates	[1]		0
Debt restructuring	[1]		0
Dividends paid to shareholders	[1]	0	0
Dividends from subsidiaries	[1]		(20,000)
Purchase of A ordinary shares	[1]	0	0
Net cash provided by (used for) financing activities	[1]	0	(20,000)
Net change in cash and cash equivalents	[1]	(19,626)	(16,936)
Cash and cash equivalents at beginning of period	[1]	71,237	55,576
Cash and cash equivalents at end of period	[1]	$ 51,611	$ 38,640

[1] Includes all other subsidiaries of Global Indemnity Limited and eliminations