CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investment advisor compensation	$ 19,863	$ 24,543	$ 19,246
Revenues
Gross premiums written	692,651	536,072	502,124
Gross premiums ceded	(56,587)	(10,015)	(9,001)
Net premiums written	636,064	526,057	493,123
Change in net unearned premium reserves	(10,060)	(12,939)	(84,736)
Net premiums earned	626,004	513,118	408,387
Net investment income (loss) [net of related party expenses of $19,863, $24,543 and $19,246]	20,231	76,183	(281,924)
Other income (expense), net	(560)	(935)	(3,413)
Total revenues	645,675	588,366	123,050
Expenses
Loss and loss adjustment expenses incurred, net	502,404	380,815	317,097
Acquisition costs, net	161,740	134,534	116,207
General and administrative expenses	26,356	25,808	23,434
Total expenses	690,500	541,157	456,738
Income (loss) before income tax	(44,825)	47,209	(333,688)
Income tax (expense) benefit	451	(509)	1,755
Net income (loss) including non-controlling interest	(44,374)	46,700	(331,933)
Loss (income) attributable to non-controlling interest in related party joint venture	(578)	(1,819)	5,508
Net income (loss)	$ (44,952)	$ 44,881	$ (326,425)
Earnings (loss) per share
Basic	$ (1.21)	$ 1.20	$ (8.90)
Diluted	$ (1.21)	$ 1.20	$ (8.90)
Weighted average number of ordinary shares used in the determination of earnings and loss per share
Basic	37,002,260	37,267,145	36,670,466
Diluted	37,002,260	37,340,018	36,670,466
Board of Directors Chairman [Member] | Investment Advisory Agreement [Member]
Performance compensation	$ (2,079)	$ (8,244)	$ 0
Management fees	17,785	16,299	19,246
Investment advisor compensation	$ 19,863	$ 24,543	$ 19,246