Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Gross written premiums	$ 1,470,735	$ 1,166,773	$ 1,081,905
Ceded written premiums	(574,585)	(404,101)	(315,279)
Net written premiums	896,150	762,672	766,626
Change in net unearned premiums	(72,404)	52,726	(25,517)
Net earned premiums	823,746	815,398	741,109
Net investment income	75,652	61,256	61,119
Net realized and unrealized losses on investments	(2,919)	(5,479)	(1,989)
Other income	10,646	14,424	17,386
Total revenues	907,125	885,599	817,625
Expenses:
Losses and loss adjustment expenses	672,102	600,276	555,377
Other operating expenses	170,908	201,035	196,993
Other expenses	1,055	1,300	539
Interest expense	10,596	11,553	8,974
Amortization of intangible assets	597	597	597
Total expenses	855,258	814,761	762,480
Income before income taxes	51,867	70,838	55,145
Income tax expense (benefit):
Current	18,453	12,867	11,943
Deferred	(4,925)	(5,859)	(364)
Total income tax expense	13,528	7,008	11,579
Net income	38,339	63,830	43,566
Other comprehensive income (losses):
Net unrealized gains (losses), net of taxes of $3,358 in 2019, $(444) in 2018, and $2,707 in 2017	46,942	(22,203)	9,219
Total comprehensive income	$ 85,281	$ 41,627	$ 52,785
Per share data:
Basic earnings per share (in dollars per share)	$ 1.27	$ 2.14	$ 1.48
Diluted earnings per share (in dollars per share)	1.25	2.11	1.44
Dividend declared per share (in dollars per share)	$ 1.20	$ 1.20	$ 1.70
Weighted-average common shares outstanding:
Basic (in shares)	30,275,184	29,887,990	29,461,717
Diluted (in shares)	30,673,924	30,307,101	30,273,149