Condensed Consolidated Statements of Income and Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues
Gross written premiums	$ 281,475	$ 170,671	$ 505,654	$ 303,742
Ceded written premiums	(73,651)	(37,613)	(139,920)	(63,783)
Net written premiums	207,824	133,058	365,734	239,959
Change in net unearned premiums	(23,747)	(14,503)	(26,970)	(4,274)
Net earned premiums	184,077	118,555	338,764	235,685
Net investment income	13,714	11,553	30,447	22,825
Net realized investment gains	307	1,619	1,354	2,166
Other income	4,296	2,784	8,231	5,164
Total revenues	202,394	134,511	378,796	265,840
Expenses
Losses and loss adjustment expenses	131,084	76,659	236,453	150,165
Other operating expenses	53,036	39,974	101,929	81,153
Other expenses	346	91	232	79
Interest expense	2,224	2,041	4,347	4,215
Amortization of intangible assets	149	149	298	298
Total expenses	186,839	118,914	343,259	235,910
Income before taxes	15,555	15,597	35,537	29,930
Income tax expense	1,014	1,001	2,546	2,497
Net income	14,541	14,596	32,991	27,433
Other comprehensive income:
Net unrealized gains, net of taxes of $1,157 and $2,671 in 2017 and $1,987 and $2,644 in 2016	6,708	12,792	10,742	28,412
Total comprehensive income	$ 21,249	$ 27,388	$ 43,733	$ 55,845
Per share data:
Basic earnings per share (in dollars per share)	$ 0.49	$ 0.50	$ 1.12	$ 0.95
Diluted earnings per share (in dollars per share)	0.48	0.49	1.09	0.92
Dividend declared per share (in dollars per share)	$ 0.30	$ 0.20	$ 0.60	$ 0.40
Weighted-average common shares outstanding:
Basic (in shares)	29,406,877	29,035,512	29,348,557	28,994,260
Diluted (in shares)	30,307,099	29,825,914	30,317,585	29,784,083