Schedule II. Condensed Financial Statements of Parent Company (Condensed Statement of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities
Net income	$ 11,995	$ 12,368	$ 3,114	$ 22,427	$ 30,895	$ 19,534	$ 15,018	$ 23,679	$ 49,904	$ 89,126	$ 59,137
Adjustments to reconcile net income to net cash provided by operating activities
Other, net									(10,743)	(3,160)	(2,813)
Total adjustments									164,480	100,872	92,154
Net cash provided by operating activities									214,384	189,998	151,291
Cash flows from investing activities
Purchase of held-to-maturity investments									(42)	(450)	0
Net cash used in investing activities									(112,403)	(36,286)	(58,878)
Cash flows from financing activities
Repurchase of common stock									(3,746)	(2,423)	(12,942)
Issuance of common stock									9,922	5,496	2,260
Tax impact from issuance of common stock									(816)	(833)	(160)
Net cash used in financing activities									(97,577)	(137,837)	(94,032)
Net Change in Cash and Cash Equivalents									4,404	15,875	(1,619)
Cash and Cash Equivalents at Beginning of Year				106,449				90,574	106,449	90,574	92,193
Cash and Cash Equivalents at End of Year	110,853				106,449				110,853	106,449	90,574
United Fire Group, Inc.
Cash flows from operating activities
Net income									49,904	89,126	59,137
Adjustments to reconcile net income to net cash provided by operating activities
Equity in net income of subsidiary									(49,908)	(89,175)	(59,305)
Dividends received from subsidiary									24,000	22,500	29,000
Other, net									2,995	1,269	700
Total adjustments									(22,913)	(65,406)	(29,605)
Net cash provided by operating activities									26,991	23,720	29,532
Cash flows from investing activities
Purchase of held-to-maturity investments									0	0	0
Net cash used in investing activities									0	0	0
Cash flows from financing activities
Repurchase of common stock									(3,746)	(2,423)	(12,942)
Issuance of common stock									9,922	5,496	2,260
Tax impact from issuance of common stock									(816)	(833)	(160)
Payment of cash dividends									(24,591)	(21,658)	(19,680)
Net cash used in financing activities									(19,231)	(19,418)	(30,522)
Net Change in Cash and Cash Equivalents									7,760	4,302	(990)
Cash and Cash Equivalents at Beginning of Year				$ 6,565				$ 2,263	6,565	2,263	3,253
Cash and Cash Equivalents at End of Year	$ 14,325				$ 6,565				$ 14,325	$ 6,565	$ 2,263