STATUTORY REPORTING, CAPITAL REQUIREMENTS AND DIVIDENDS AND RETAINED EARNINGS RESTRICTIONS (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Feb. 02, 2016	Jun. 04, 2013
Statutory Accounting Practices [Line Items]
Maximum borrowing capacity	$ 100,000,000
Payment of cash dividends	(24,591,000)	$ (21,658,000)	$ (19,680,000)
United Fire & Casualty Company
Statutory Accounting Practices [Line Items]
Intercompany dividend payments that are eliminated in Consolidated Financial Statements	24,000,000	22,500,000	29,000,000
Subsidiaries
Statutory Accounting Practices [Line Items]
Intercompany dividend payments that are eliminated in Consolidated Financial Statements	26,000,000	$ 16,500,000	$ 13,500,000
United Life
Statutory Accounting Practices [Line Items]
Statutory basis	1,524,559,000
Net assets on statutory basis, in excess of the legal reserve requirement	200,238,000
Revolving Credit Facility
Statutory Accounting Practices [Line Items]
Maximum borrowing capacity	50,000,000			$ 50,000,000	$ 125,000,000
State of Iowa Insurance Department
Statutory Accounting Practices [Line Items]
Maximum dividend distribution without prior approval	$ 53,091,000