Schedule II - Condensed Financial Information of Registrant, Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue [Abstract]
Net investment income	$ 6,321	$ 5,486	$ 6,379	$ 7,236	$ 6,815	$ 6,703	$ 6,500	$ 6,231	$ 25,422	$ 26,249	$ 22,048
Net realized losses on investments	7,761	144	10,615	(27,756)	3,848	125	2,889	6,027	(9,236)	12,889	(25,691)
Total revenues									468,749	495,597	439,169
Expenses [Abstract]
Other									143,428	138,456	137,177
Total expenses									462,386	486,924	483,041
Federal income tax benefit									1,900	1,326	(9,797)
Net income (loss)	$ 11,971	$ 3,281	$ 11,367	$ (22,156)	$ 3,771	$ (707)	$ 1,535	$ 2,748	4,463	7,347	(34,075)
Protective Insurance Corporation [Member]
Revenue [Abstract]
Commissions and service fees									15,011	14,149	17,456
Cash dividends from subsidiaries									0	0	5,000
Net investment income									453	692	569
Net realized losses on investments									(10)	(46)	(192)
Other									138	17	51
Total revenues									15,592	14,812	22,884
Expenses [Abstract]
Salary and related items									10,663	11,804	20,158
Other									11,048	10,386	11,724
Total expenses									21,711	22,190	31,882
Loss before federal income tax benefit and equity in undistributed income of subsidiaries									(6,119)	(7,378)	(8,998)
Federal income tax benefit									(1,333)	(1,452)	(2,862)
Loss after federal income tax benefit and equity in undistributed income of subsidiaries									(4,786)	(5,926)	(6,136)
Equity in undistributed income of subsidiaries									9,249	13,273	(27,939)
Net income (loss)									$ 4,463	$ 7,347	$ (34,075)