Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Gross written premiums	$ 389,694	$ 275,538	$ 223,191
Ceded written premiums	(47,633)	(39,924)	(33,719)
Net written premiums	342,061	235,614	189,472
Change in unearned premiums	(59,080)	(22,926)	(13,419)
Net earned premiums	282,981	212,688	176,053
Net investment income	20,133	15,688	10,569
Change in fair value of equity securities	12,389	(6,555)	0
Net realized investment gains	359	281	151
Other income	26	12	3
Total revenues	315,888	222,114	186,776
Expenses:
Losses and loss adjustment expenses	169,563	128,041	103,680
Underwriting, acquisition and insurance expenses	70,217	53,425	44,146
Other expenses	57	168	429
Total expenses	239,837	181,634	148,255
Income before income taxes	76,051	40,480	38,521
Income tax expense (benefit)	12,735	6,693	13,620
Net income	63,316	33,787	24,901
Other comprehensive income (loss):
Change in unrealized gains (losses) on available-for-sale investments, net of taxes of $3,927 in 2019, $(1,453) in 2018, and $3,047 in 2017	14,774	(5,469)	6,384
Total comprehensive income	$ 78,090	$ 28,318	$ 31,285
Earnings per share:
Basic	$ 2.94	$ 1.60	$ 1.19
Diluted	$ 2.86	$ 1.56	$ 1.16
Weighted-average common shares outstanding:
Basic	21,528	21,090	20,992
Diluted	22,136	21,685	21,498