Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Gross written premiums	$ 275,538	$ 223,191	$ 188,478
Ceded written premiums	(39,924)	(33,719)	(21,214)
Net written premiums	235,614	189,472	167,264
Change in unearned premiums	(22,926)	(13,419)	(33,448)
Net earned premiums	212,688	176,053	133,816
Net investment income	15,688	10,569	7,487
Net unrealized losses on equity securities	(6,555)	0	0
Net realized investment gains, excluding other-than-temporary impairment losses	281	151	452
Other-than-temporary impairment losses	0	0	(276)
Other income	12	3	136
Total revenues	222,114	186,776	141,615
Expenses:
Losses and loss adjustment expenses	128,041	103,680	70,961
Underwriting, acquisition and insurance expenses	53,425	44,146	28,551
Other expenses	168	429	2,567
Total expenses	181,634	148,255	102,079
Income before income taxes	40,480	38,521	39,536
Income tax expense	6,693	13,620	13,369
Net income	33,787	24,901	26,167
Other comprehensive income (loss):
Change in unrealized gains (losses) on available-for-sale investments, net of taxes of $(1,453) in 2018, $3,047 in 2017, and $(344) in 2016	(5,469)	6,384	(640)
Total comprehensive income	$ 28,318	$ 31,285	$ 25,527
Common Stock [Member]
Earnings per share:
Basic	$ 1.60	$ 1.19	$ 0.57
Diluted	$ 1.56	$ 1.16	$ 0.56
Weighted-average common shares outstanding:
Basic	21,090	20,992	20,841
Diluted	21,685	21,498	21,073
Class A Common Stock [Member]
Earnings per share:
Basic	$ 0.00	$ 0.00	$ 0.98
Diluted	$ 0.00	$ 0.00	$ 0.98
Weighted-average common shares outstanding:
Basic	0	0	13,844
Diluted	0	0	13,844
Class B Common Stock [Member]
Earnings per share:
Basic	$ 0.00	$ 0.00	$ 0.48
Diluted	$ 0.00	$ 0.00	$ 0.46
Weighted-average common shares outstanding:
Basic	0	0	1,574
Diluted	0	0	1,644