Schedule II. Condensed Financial Statements of Parent Company (Condensed Statement of Income and Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues
Investment income									$ 104,609	$ 112,799	$ 111,905
Total revenues	250,452	235,865	232,673	222,904	228,994	223,024	219,719	205,305	941,894	877,042	813,243
Expenses
Income before income taxes	50,355	(2,845)	13,056	15,897	37,339	14,395	20,318	29,850	76,463	101,902	46,074
Federal income tax benefit									17,326	25,762	5,862
Net income	34,796	325	10,685	13,331	26,526	11,725	15,496	22,393	59,137	76,140	40,212
Other comprehensive income (loss)
Change in unrealized appreciation on investments held by subsidiary									55,888	(35,489)	34,436
Change in liability for underfunded employee benefit plans									(47,685)	24,066	(15,922)
Other comprehensive income (loss), before tax and reclassification adjustments									8,203	(11,423)	18,514
Income tax effect									(2,871)	3,998	(6,477)
Other comprehensive income (loss), after tax, before reclassification adjustments									5,332	(7,425)	12,037
Reclassifications for unrealized net gains on available-for-sale securities									(5,085)	(6,812)	(4,102)
Reclassification adjustment for employee benefit costs included in expense									3,072	5,868	4,971
Total reclassification adjustments, before tax									(2,013)	(944)	869
Income tax effect									704	331	(304)
Total reclassification adjustments, after tax									(1,309)	(613)	565
Comprehensive income									63,160	68,102	52,814
United Fire Group, Inc. [Member]
Revenues
Investment income									22	23	13	[1]
Total revenues									22	23	13	[1]
Expenses
Other operating expenses									297	172	158	[1]
Total expenses									297	172	158	[1]
Income before income taxes									(275)	(149)	(145)	[1]
Federal income tax benefit									(107)	(49)	(51)	[1]
Net loss before equity in net income of subsidiary									(168)	(100)	(94)	[1]
Equity in net income of subsidiary									59,305	76,240	40,306	[1],[2]
Net income									59,137	76,140	40,212	[1],[2]
Other comprehensive income (loss)
Change in unrealized appreciation on investments held by subsidiary									55,888	(35,489)	34,436	[1]
Change in liability for underfunded employee benefit plans									(47,685)	24,066	(15,922)	[1]
Other comprehensive income (loss), before tax and reclassification adjustments									8,203	(11,423)	18,514	[1]
Income tax effect									(2,871)	3,998	(6,477)	[1]
Other comprehensive income (loss), after tax, before reclassification adjustments									5,332	(7,425)	12,037	[1]
Reclassifications for unrealized net gains on available-for-sale securities									(5,085)	(6,812)	(4,102)	[1]
Reclassification adjustment for employee benefit costs included in expense									3,072	5,868	4,971	[1]
Total reclassification adjustments, before tax									(2,013)	(944)	869	[1]
Income tax effect									704	331	(304)	[1]
Total reclassification adjustments, after tax									(1,309)	(613)	565	[1]
Comprehensive income									$ 63,160	$ 68,102	$ 52,814	[1]

[1] The Condensed Statement of Income and Comprehensive Income includes the full year 2012 results. The results of January 2012 are immaterial to the full year 2012 results.

[2] The Condensed Statement of Cash Flows includes the full year 2012 results. The results of January 2012 are immaterial to the full year 2012 results.