Segment Information - Summary of Operations by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
INCOME
Net premiums earned	$ 226,928	$ 212,023	$ 436,337	$ 410,929
Fees and commission income	7,243	9,131	12,590	20,611
Net investment income	54,223	34,655	114,286	65,072
Net realized and unrealized gains (losses)	37,987	(11,249)	75,951	31,771
Other income	4,048	11,838	6,461	15,314
Total income	330,429	256,398	645,625	543,697
EXPENSES
Net incurred losses and LAE	96,462	65,900	179,680	136,036
Life and annuity policy benefits	19,778	28,090	40,758	50,937
Acquisition costs	46,489	37,094	93,754	71,644
General and administrative expenses	105,878	93,963	200,324	190,561
Interest expense	5,424	4,876	10,825	8,879
Net foreign exchange losses (gains)	(1,856)	2,452	(84)	(2,619)
Total expenses	272,175	232,375	525,257	455,438
EARNINGS BEFORE INCOME TAXES	58,254	24,023	120,368	88,259
INCOME TAXES	(8,473)	(5,816)	(15,982)	(16,560)
NET EARNINGS	49,781	18,207	104,386	71,699
Less: Net losses (earnings) attributable to noncontrolling interest	(9,187)	(3,662)	(18,272)	(12,307)
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED	40,594	14,545	86,114	59,392
Atrium
INCOME
Net premiums earned	31,758	33,957	63,669	67,829
EXPENSES
Net incurred losses and LAE	17,133	13,757	32,722	20,777
StarStone
INCOME
Net premiums earned	171,035	137,696	325,117	261,318
EXPENSES
Net incurred losses and LAE	104,019	81,013	195,202	157,229
Operating Segments | Non-life Run-off
INCOME
Net premiums earned	4,476	17,298	9,911	35,790
Fees and commission income	865	4,892	7,431	9,729
Net investment income	37,581	18,569	73,811	37,433
Net realized and unrealized gains (losses)	26,161	(4,308)	49,551	30,352
Other income	2,036	9,875	3,836	12,915
Total income	71,119	46,326	144,540	126,219
EXPENSES
Net incurred losses and LAE	(24,690)	(28,870)	(48,244)	(41,970)
Life and annuity policy benefits	0	0	0	0
Acquisition costs	(56)	(5,871)	1,926	(7,576)
General and administrative expenses	61,449	53,168	119,562	108,159
Interest expense	6,016	2,826	11,496	5,346
Net foreign exchange losses (gains)	(3,096)	(4,543)	(2,216)	595
Total expenses	39,623	16,710	82,524	64,554
EARNINGS BEFORE INCOME TAXES	31,496	29,616	62,016	61,665
INCOME TAXES	(3,486)	(6,104)	(8,159)	(11,211)
NET EARNINGS	28,010	23,512	53,857	50,454
Less: Net losses (earnings) attributable to noncontrolling interest	(2,370)	(3,761)	(3,085)	(3,357)
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED	25,640	19,751	50,772	47,097
Operating Segments | Atrium
INCOME
Net premiums earned	31,758	33,957	63,669	67,829
Fees and commission income	6,378	7,457	10,210	16,985
Net investment income	635	523	1,189	1,030
Net realized and unrealized gains (losses)	68	38	108	129
Other income	65	76	99	154
Total income	38,904	42,051	75,275	86,127
EXPENSES
Net incurred losses and LAE	17,133	13,757	32,722	20,777
Life and annuity policy benefits	0	0	0	0
Acquisition costs	11,240	12,301	22,327	21,707
General and administrative expenses	6,629	6,670	13,037	18,293
Interest expense	0	1,482	0	2,965
Net foreign exchange losses (gains)	256	2,213	2,071	(302)
Total expenses	35,258	36,423	70,157	63,440
EARNINGS BEFORE INCOME TAXES	3,646	5,628	5,118	22,687
INCOME TAXES	(580)	(2,252)	(1,258)	(4,136)
NET EARNINGS	3,066	3,376	3,860	18,551
Less: Net losses (earnings) attributable to noncontrolling interest	(1,258)	(1,982)	(1,584)	(8,710)
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED	1,808	1,394	2,276	9,841
Operating Segments | StarStone
INCOME
Net premiums earned	171,035	137,696	325,117	261,318
Fees and commission income	0	0	0	14
Net investment income	5,753	4,058	11,033	6,189
Net realized and unrealized gains (losses)	8,021	(3,355)	22,370	1,347
Other income	1,584	1,303	1,595	1,366
Total income	186,393	139,702	360,115	270,234
EXPENSES
Net incurred losses and LAE	104,019	81,013	195,202	157,229
Life and annuity policy benefits	0	0	0	0
Acquisition costs	32,518	27,365	64,578	51,508
General and administrative expenses	31,311	32,891	61,466	63,104
Interest expense	0	0	0	0
Net foreign exchange losses (gains)	1,027	4,200	(272)	(2,180)
Total expenses	168,875	145,469	320,974	269,661
EARNINGS BEFORE INCOME TAXES	17,518	(5,767)	39,141	573
INCOME TAXES	(3,970)	694	(5,988)	12
NET EARNINGS	13,548	(5,073)	33,153	585
Less: Net losses (earnings) attributable to noncontrolling interest	(5,559)	2,081	(13,603)	(240)
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED	7,989	(2,992)	19,550	345
Operating Segments | Life and Annuities
INCOME
Net premiums earned	19,659	23,072	37,640	45,992
Fees and commission income	0	0	0	0
Net investment income	11,113	11,577	29,534	20,652
Net realized and unrealized gains (losses)	3,737	(3,624)	3,922	(57)
Other income	363	584	931	879
Total income	34,872	31,609	72,027	67,466
EXPENSES
Net incurred losses and LAE	0	0	0	0
Life and annuity policy benefits	19,778	28,090	40,758	50,937
Acquisition costs	2,804	3,299	5,206	6,005
General and administrative expenses	6,467	4,452	11,027	7,122
Interest expense	272	640	610	800
Net foreign exchange losses (gains)	(43)	582	333	(732)
Total expenses	29,278	37,063	57,934	64,132
EARNINGS BEFORE INCOME TAXES	5,594	(5,454)	14,093	3,334
INCOME TAXES	(437)	1,846	(577)	(1,225)
NET EARNINGS	5,157	(3,608)	13,516	2,109
Less: Net losses (earnings) attributable to noncontrolling interest	0	0	0	0
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED	5,157	(3,608)	13,516	2,109
Eliminations
INCOME
Net premiums earned	0	0	0	0
Fees and commission income	0	(3,218)	(5,051)	(6,117)
Net investment income	(859)	(72)	(1,281)	(232)
Net realized and unrealized gains (losses)	0	0	0	0
Other income	0	0	0	0
Total income	(859)	(3,290)	(6,332)	(6,349)
EXPENSES
Net incurred losses and LAE	0	0	0	0
Life and annuity policy benefits	0	0	0	0
Acquisition costs	(17)	0	(283)	0
General and administrative expenses	22	(3,218)	(4,768)	(6,117)
Interest expense	(864)	(72)	(1,281)	(232)
Net foreign exchange losses (gains)	0	0	0	0
Total expenses	(859)	(3,290)	(6,332)	(6,349)
EARNINGS BEFORE INCOME TAXES	0	0	0	0
INCOME TAXES	0	0	0	0
NET EARNINGS	0	0	0	0
Less: Net losses (earnings) attributable to noncontrolling interest	0	0	0	0
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED	$ 0	$ 0	$ 0	$ 0