Schedule II. Condensed Financial Statements of Parent Company (Condensed Statement of Income and Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues
Investment income	$ 44,932	$ 55,778	$ 39,670
Total revenues	980,286	1,066,191	1,068,627
Expenses
Net income (loss)	15,031	80,594	(112,706)
Other comprehensive income (loss)
Change in unrealized appreciation on investments held by subsidiary	(176,181)	(39,901)	47,054
Change in liability for underfunded employee benefit plans of subsidiary	(8,278)	19,633	18,456
Other comprehensive income (loss), before tax and reclassification adjustments	(184,459)	(20,268)	65,510
Income tax effect	38,736	4,260	(13,757)
Reclassification adjustment for net (gains) losses included in income	1,323	(2,256)	(1,750)
Reclassification adjustment for employee benefit costs included in expense	3,601	6,603	4,289
Total reclassification adjustments, before tax	4,924	4,347	2,539
Income tax effect	(1,034)	(913)	(534)
Comprehensive income (loss)	(126,802)	68,020	(58,948)
United Fire Group, Inc.
Revenues
Investment income	85	23	141
Total revenues	85	23	141
Expenses
Other operating expenses	0	3	10
Total expenses	0	3	10
Income before income taxes and equity in net income of subsidiary	85	20	131
Federal income tax expense (benefit)	18	5	68
Net income before equity in net income (loss) of subsidiary	67	15	63
Equity in net income (loss) of subsidiary	14,964	80,579	(112,769)
Net income (loss)	15,031	80,594	(112,706)
Other comprehensive income (loss)
Change in unrealized appreciation on investments held by subsidiary	(176,183)	(39,901)	47,054
Change in liability for underfunded employee benefit plans of subsidiary	(8,277)	19,633	18,456
Other comprehensive income (loss), before tax and reclassification adjustments	(184,460)	(20,268)	65,510
Income tax effect	38,736	4,260	(13,757)
Other comprehensive income (loss), after tax, before reclassification adjustments	(145,724)	(16,008)	51,753
Reclassification adjustment for net (gains) losses included in income	1,323	(2,256)	(1,750)
Reclassification adjustment for employee benefit costs included in expense	3,601	6,603	4,289
Total reclassification adjustments, before tax	4,924	4,347	2,539
Income tax effect	(1,034)	(913)	(534)
Total reclassification adjustments, after tax	3,890	3,434	2,005
Comprehensive income (loss)	$ (126,803)	$ 68,020	$ (58,948)