Segment Information - Summary of Operations by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
INCOME
Net premiums earned	$ 209,409	$ 198,906
Fees and commission income	5,347	11,480
Net investment income	60,063	30,415
Net realized and unrealized gains (losses)	37,964	43,020
Other income	2,413	3,478
Total income	315,196	287,299
EXPENSES
Net incurred losses and LAE	83,218	70,136
Life and annuity policy benefits	20,980	22,847
Acquisition costs	47,265	34,550
Salaries and benefits	57,560	57,772
General and administrative expenses	36,886	38,826
Interest expense	5,401	4,003
Net foreign exchange losses (gains)	1,772	(5,071)
Total expenses	253,082	223,063
EARNINGS BEFORE INCOME TAXES	62,114	64,236
INCOME TAXES	(7,509)	(10,744)
NET EARNINGS	54,605	53,492
Less: Net losses (earnings) attributable to noncontrolling interest	(9,085)	(8,645)
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED	45,520	44,847
Operating Segments | Non-Life Run-Off
INCOME
Net premiums earned	5,435	18,492
Fees and commission income	6,566	4,837
Net investment income	36,230	18,864
Net realized and unrealized gains (losses)	23,390	34,660
Other income	1,800	3,040
Total income	73,421	79,893
EXPENSES
Net incurred losses and LAE	(23,554)	(13,100)
Life and annuity policy benefits	0	0
Acquisition costs	1,982	(1,705)
Salaries and benefits	35,697	32,044
General and administrative expenses	22,416	22,947
Interest expense	5,480	2,520
Net foreign exchange losses (gains)	880	5,138
Total expenses	42,901	47,844
EARNINGS BEFORE INCOME TAXES	30,520	32,049
INCOME TAXES	(4,673)	(5,107)
NET EARNINGS	25,847	26,942
Less: Net losses (earnings) attributable to noncontrolling interest	(715)	404
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED	25,132	27,346
Operating Segments | Atrium
INCOME
Net premiums earned	31,911	33,872
Fees and commission income	3,832	9,528
Net investment income	554	506
Net realized and unrealized gains (losses)	40	91
Other income	34	79
Total income	36,371	44,076
EXPENSES
Net incurred losses and LAE	15,589	7,020
Life and annuity policy benefits	0	0
Acquisition costs	11,087	9,406
Salaries and benefits	2,858	8,169
General and administrative expenses	3,550	3,454
Interest expense	0	1,483
Net foreign exchange losses (gains)	1,815	(2,515)
Total expenses	34,899	27,017
EARNINGS BEFORE INCOME TAXES	1,472	17,059
INCOME TAXES	(678)	(1,884)
NET EARNINGS	794	15,175
Less: Net losses (earnings) attributable to noncontrolling interest	(326)	(6,728)
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED	468	8,447
Operating Segments | StarStone Segment
INCOME
Net premiums earned	154,082	123,622
Fees and commission income	0	14
Net investment income	5,280	2,130
Net realized and unrealized gains (losses)	14,349	4,702
Other income	11	64
Total income	173,722	130,532
EXPENSES
Net incurred losses and LAE	91,183	76,216
Life and annuity policy benefits	0	0
Acquisition costs	32,060	24,143
Salaries and benefits	17,849	15,420
General and administrative expenses	12,306	14,793
Interest expense	0	0
Net foreign exchange losses (gains)	(1,299)	(6,380)
Total expenses	152,099	124,192
EARNINGS BEFORE INCOME TAXES	21,623	6,340
INCOME TAXES	(2,018)	(682)
NET EARNINGS	19,605	5,658
Less: Net losses (earnings) attributable to noncontrolling interest	(8,044)	(2,321)
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED	11,561	3,337
Operating Segments | Life and Annuities
INCOME
Net premiums earned	17,981	22,920
Fees and commission income	0	0
Net investment income	18,421	9,075
Net realized and unrealized gains (losses)	185	3,567
Other income	568	295
Total income	37,155	35,857
EXPENSES
Net incurred losses and LAE	0	0
Life and annuity policy benefits	20,980	22,847
Acquisition costs	2,402	2,706
Salaries and benefits	1,156	2,139
General and administrative expenses	3,404	531
Interest expense	338	160
Net foreign exchange losses (gains)	376	(1,314)
Total expenses	28,656	27,069
EARNINGS BEFORE INCOME TAXES	8,499	8,788
INCOME TAXES	(140)	(3,071)
NET EARNINGS	8,359	5,717
Less: Net losses (earnings) attributable to noncontrolling interest	0	0
NET EARNINGS ATTRIBUTABLE TO ENSTAR GROUP LIMITED	8,359	5,717
Eliminations
INCOME
Fees and commission income	(5,051)	(2,899)
Net investment income	(422)	(160)
Total income	(5,473)	(3,059)
EXPENSES
Acquisition costs	(266)
General and administrative expenses	(4,790)	(2,899)
Interest expense	(417)	(160)
Total expenses	$ (5,473)	$ (3,059)