Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
REVENUE:
Gross premiums written	$ 586,098	$ 436,407	$ 218,537
Increase in gross unearned premiums	(61,358)	(124,893)	(78,578)
Gross premiums earned	524,740	311,514	139,959
Ceded premiums	(148,472)	(87,902)	(44,800)
Net premiums earned	376,268	223,612	95,159
Retroactive reinsurance			26,046
Net investment income	7,421	3,849	1,049
Net realized gains (losses)	1,508	304	(323)
Other revenue	9,595	6,055	2,901
Total revenue	394,792	233,820	124,832
EXPENSES:
Losses and loss adjustment expenses	141,191	89,560	38,501
Policy acquisition costs	57,186	36,510	6,150
General and administrative expenses	46,125	33,498	24,720
Total expenses	244,502	159,568	69,371
Income before income taxes	150,290	74,252	55,461
Provision for income taxes	57,778	27,155	21,248
Net income	92,512	47,097	34,213
OTHER COMPREHENSIVE INCOME:
Change in net unrealized (losses) gains on investments	(4,606)	4,395	(1,610)
Reclassification adjustment for net realized investment (losses) gains	(1,508)	(304)	323
Income tax (expense) benefit related to items of other comprehensive income	2,358	(1,578)	497
Total comprehensive income	$ 88,756	$ 49,610	$ 33,423
Weighted average shares outstanding
Basic	30,056,491	24,568,876	14,313,150
Diluted	30,326,468	25,816,560	14,473,800
Earnings per share
Basic	$ 3.08	$ 1.92	$ 2.39
Diluted	$ 3.05	$ 1.82	$ 2.36