Schedule II. Condensed Financial Statements of Parent Company (Condensed Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Available-for-sale, at fair value (amortized cost $1,720,291 in 2020 and $1,659,760 in 2019; allowance for credit losses $5 in 2020 and $— in 2019)	$ 1,825,438	$ 1,719,607
Cash and cash equivalents	87,948	120,722
Other assets	37,196	29,905
Total assets	3,069,678	3,013,472
Liabilities and stockholders' equity
Liabilities	2,244,529	2,103,000
Stockholders' equity
Common Stock, Value, Issued	25	25
Additional paid-in capital	202,359	200,179
Retained earnings	555,854	697,116
Accumulated other comprehensive income, net of tax	66,911	13,152
Total stockholders' equity	825,149	910,472	$ 888,375	$ 973,373
Total liabilities and stockholders' equity	3,069,678	3,013,472
United Fire Group, Inc.
Assets
Available-for-sale, at fair value (amortized cost $1,720,291 in 2020 and $1,659,760 in 2019; allowance for credit losses $5 in 2020 and $— in 2019)	150	150
Investment in subsidiary	818,581	880,485
Cash and cash equivalents	6,504	29,878
Other assets	15	3
Total assets	825,250	910,516
Liabilities and stockholders' equity
Liabilities	101	44
Stockholders' equity
Common Stock, Value, Issued	25	25
Additional paid-in capital	202,359	200,179
Retained earnings	555,854	697,116
Accumulated other comprehensive income, net of tax	66,911	13,152
Total stockholders' equity	825,149	910,472
Total liabilities and stockholders' equity	$ 825,250	$ 910,516