Segment Information - Summary of Operations by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
INCOME
Net premiums earned	$ 197,091	$ 231,051	$ 212,023	$ 198,906	$ 171,889	$ 195,987	$ 216,916	$ 61,658	$ 839,071	$ 646,450	$ 239,807
Fees and commission income	6,317	8,977	9,131	11,480	11,771	6,801	7,509	6,998	35,905	33,079	12,817
Net investment income	51,599	40,286	34,779	30,990	24,889	25,706	26,485	24,326	157,654	101,406	89,920
Net realized and unrealized gains (losses)	(57,893)	(15,130)	(11,249)	43,020	7,971	(18,336)	38,411	34,573	(41,252)	62,619	70,651
Other income	20,519	2,883	11,714	2,903	6,499	2,278	7,164	22	38,019	15,963	3,375
Total income	217,633	268,067	256,398	287,299	223,019	212,436	296,485	127,577	1,029,397	859,517	416,570
EXPENSES
Net incurred losses and LAE	(64,062)	32,359	65,900	70,136	(56,085)	17,533	59,749	(12,051)	104,333	9,146	(163,672)
Life and annuity policy benefits	23,000	22,989	28,090	22,847	4,309	26,549	50,379	26,809	96,926	108,046	78,354
Acquisition costs	55,980	49,806	37,094	34,550	55,419	36,261	27,732	13,161	177,430	132,573	23,199
Salaries and benefits	72,685	55,440	52,691	57,772	69,624	54,525	55,683	31,390	238,588	211,222	124,616
General and administrative expenses	36,020	44,895	41,272	38,826	40,804	41,039	37,177	22,250	161,013	141,270	86,612
Interest expense	5,368	5,156	4,876	4,003	2,352	3,307	3,529	3,734	19,403	12,922	12,389
Net foreign exchange losses (gains)	7,005	(841)	2,452	(5,071)	(1,476)	6,365	(525)	1,596	3,545	5,960	(4,369)
Total expenses	135,996	209,804	232,375	223,063	114,947	185,579	233,724	86,889	801,238	621,139	157,129
EARNINGS BEFORE INCOME TAXES	81,637	58,263	24,023	64,236	108,072	26,857	62,761	40,688	228,159	238,378	259,441
INCOME TAXES	11,004	(12,262)	(5,816)	(10,744)	10,246	(5,660)	(8,452)	(7,276)	(17,818)	(11,142)	(35,619)
NET EARNINGS	92,641	46,001	18,207	53,492	118,318	21,197	54,309	33,412	210,341	227,236	223,822
Less: Net loss (earnings) attributable to noncontrolling interest	19,216	3,041	(3,662)	(8,645)	(12,378)	5,232	(2,516)	(3,825)	9,950	(13,487)	(15,218)
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED	$ 111,857	$ 49,042	$ 14,545	$ 44,847	$ 105,940	$ 26,429	$ 51,793	$ 29,587	220,291	213,749	208,604
Operating Segments | Non-Life Run-Off
INCOME
Net premiums earned									44,369	31,168	112,611
Fees and commission income									21,366	19,342	12,785
Net investment income									84,185	57,899	61,925
Net realized and unrealized gains (losses)									(31,193)	48,030	79,368
Other income									29,293	13,310	2,123
Total income									148,020	169,749	268,812
EXPENSES
Net incurred losses and LAE									(270,830)	(264,711)	(182,975)
Life and annuity policy benefits									0	0	0
Acquisition costs									8,860	8,393	14,379
Salaries and benefits									148,592	127,776	117,141
General and administrative expenses									90,397	70,287	67,979
Interest expense									14,565	7,493	12,057
Net foreign exchange losses (gains)									4,372	8,015	(5,909)
Total expenses									(4,044)	(42,747)	22,672
EARNINGS BEFORE INCOME TAXES									152,064	212,496	246,140
INCOME TAXES									(12,570)	622	(34,191)
NET EARNINGS									139,494	213,118	211,949
Less: Net loss (earnings) attributable to noncontrolling interest									33,722	(9,836)	(12,076)
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED									173,216	203,282	199,873
Operating Segments | Atrium
INCOME
Net premiums earned									134,675	135,945	32,212
Fees and commission income									28,352	26,176	2,708
Net investment income									2,225	1,748	486
Net realized and unrealized gains (losses)									252	41	542
Other income									359	223	35
Total income									165,863	164,133	35,983
EXPENSES
Net incurred losses and LAE									47,479	55,428	19,303
Life and annuity policy benefits									0	0	0
Acquisition costs									45,509	43,417	0
Salaries and benefits									16,739	20,142	2,676
General and administrative expenses									14,871	14,779	2,716
Interest expense									4,264	5,429	332
Net foreign exchange losses (gains)									213	(1,559)	1,364
Total expenses									129,075	137,636	26,391
EARNINGS BEFORE INCOME TAXES									36,788	26,497	9,592
INCOME TAXES									(5,968)	(5,092)	(185)
NET EARNINGS									30,820	21,405	9,407
Less: Net loss (earnings) attributable to noncontrolling interest									(14,262)	(10,974)	(4,170)
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED									16,558	10,431	5,237
Operating Segments | StarStone Segment
INCOME
Net premiums earned									573,146	373,633	0
Fees and commission income									0	0	0
Net investment income									15,937	5,321	0
Net realized and unrealized gains (losses)									(9,784)	2,136	0
Other income									676	616	0
Total income									579,975	381,706	0
EXPENSES
Net incurred losses and LAE									327,684	218,429	0
Life and annuity policy benefits									0	0	0
Acquisition costs									109,347	65,734	0
Salaries and benefits									68,439	55,846	0
General and administrative expenses									57,693	57,498	2,554
Interest expense									6	0	0
Net foreign exchange losses (gains)									(480)	945	18
Total expenses									562,689	398,452	2,572
EARNINGS BEFORE INCOME TAXES									17,286	(16,746)	(2,572)
INCOME TAXES									5,888	(1,130)	0
NET EARNINGS									23,174	(17,876)	(2,572)
Less: Net loss (earnings) attributable to noncontrolling interest									(9,510)	7,323	1,028
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED									13,664	(10,553)	(1,544)
Operating Segments | Life and Annuities
INCOME
Net premiums earned									86,881	105,704	94,984
Fees and commission income									0	32	0
Net investment income									56,541	37,656	28,965
Net realized and unrealized gains (losses)									(527)	12,412	(9,259)
Other income									7,691	1,814	1,217
Total income									150,586	157,618	115,907
EXPENSES
Net incurred losses and LAE									0	0	0
Life and annuity policy benefits									96,926	108,046	78,354
Acquisition costs									13,714	15,029	8,820
Salaries and benefits									4,818	7,458	4,799
General and administrative expenses									11,865	11,177	16,039
Interest expense									1,802	1,218	1,456
Net foreign exchange losses (gains)									(560)	(1,441)	158
Total expenses									128,565	141,487	109,626
EARNINGS BEFORE INCOME TAXES									22,021	16,131	6,281
INCOME TAXES									(5,168)	(5,542)	(1,243)
NET EARNINGS									16,853	10,589	5,038
Less: Net loss (earnings) attributable to noncontrolling interest									0	0	0
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED									16,853	10,589	5,038
Eliminations
INCOME
Fees and commission income									(13,813)	(12,471)	(2,676)
Net investment income									(1,234)	(1,218)	(1,456)
Total income									(15,047)	(13,689)	(4,132)
EXPENSES
General and administrative expenses									(13,813)	(12,471)	(2,676)
Interest expense									(1,234)	(1,218)	(1,456)
Total expenses									$ (15,047)	$ (13,689)	$ (4,132)