STOCK-BASED COMPENSATION (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 Plan	Dec. 31, 2013	Dec. 31, 2012	Apr. 26, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock option plans	2
Recognized compensation expense	$ 357	$ 289	$ 240
Recognized compensation expense, net of tax	233	190	174
Excess tax benefit associated with affiliate’s stock plans	103	96	(3)
Stock Appreciation Rights plan recognized expense	15
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years	4 years
Unrecognized compensation cost associated with restricted stock awards, not currently vested	690
Weighted-average period over which the compensation expense is expected to be recognized	2 years 9 months 3 days
Total fair value of restricted stock awards that vested	110	0
Non-vested restricted stock awards activity in shares
Non-vested, beginning of year (in shares)	56,668	0
Granted (in shares)	62,764	57,720
Vested (in shares)	14,117	0
Forfeited (in shares)	(1,375)	(1,052)
Non-vested, end of year (in shares)	103,940	56,668
Non-vested restricted stock awards activity in dollars per share weighted-average grant-date fair value
Non-vested, beginning of year (in dollars per share)	$ 25.90	$ 0.00
Granted (in dollars per share)	$ 30.74	$ 25.90
Vested (in dollars per share)	$ 25.90	$ 0.00
Forfeited (in dollars per share)	$ 26.61	$ 25.90
Non-vested, end of year (in dollars per share)	$ 28.81	$ 25.90
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	5 years	5 years	5 years
Unrecognized compensation cost associated with option awards, not currently vested	194
Weighted-average period over which the compensation expense is expected to be recognized	1 year 6 months 21 days
Total intrinsic value of options exercised under Employers Mutual's stock option plans	606	844	54
Portion of the current tax deduction realized from exercises of stock options	152	165	2
Excess tax benefit associated with affiliate’s stock plans	103	96	(3)
Number of options [Roll Forward]
Outstanding, beginning of year (in shares)	1,135,207	1,588,958	1,437,095
Granted (in shares)	0	0	263,162
Exercised (in shares)	(200,304)	(406,532)	(42,619)
Expired (in shares)	(22,945)	(47,219)	(68,680)
Forfeited (in shares)	10,825	0	0
Outstanding, end of year (in shares)	901,133	1,135,207	1,588,958
Options Exercisable, end of year (in shares)	642,464	686,863	894,706
Weighted-average exercise price [Roll Forward]
Outstanding, beginning of year (in dollars per share)	$ 22.17	$ 21.89	$ 21.92
Granted (in dollars per share)	$ 0.00	$ 0.00	$ 20.98
Exercised (in dollars per share)	$ 21.36	$ 21.26	$ 17.97
Expired (in dollars per share)	$ 22.52	$ 20.35	$ 21.51
Forfeited (in dollars per share)	$ 22.94	$ 0.00	$ 0.00
Outstanding, end of year (in dollars per share)	$ 22.34	$ 22.17	$ 21.89
Exercisable, end of year (in dollars per share)	$ 22.41	$ 22.37	$ 21.96
Share-based payment award, fair value assumptions and methodology [Abstract]
Estimated dividend yield (in hundredths)			3.81%
Minimum, Expected volatility (in hundredths)			25.20%
Maximum, Expected volatility (in hundredths)			44.70%
Weighted-average volatility (in hundredths)			35.61%
Minimum, Risk-free interest rate (in hundredths)			0.06%
Maximum, Risk-free interest rate (in hundredths)			1.51%
Abbreviated period granted to option holders to exercise options retirement	90 days	90 days	90 days
Additional information relating to options outstanding and options vested (exercisable) [Abstract]
Options outstanding, Number of options (in shares)	901,133
Options outstanding, Weighted-average exercise price (in dollars per share)	$ 22.34
Options outstanding, Aggregate intrinsic value	11,164
Options outstanding, Weighted-average remaining term	4 years 3 months 18 days
Options exercisable, Number of options (in shares)	642,464
Options exercisable, Weighted-average exercise price (in dollars per share)	$ 22.41
Options exercisable, Aggregate intrinsic value	7,912
Options exercisable, Weighted-average remaining term	3 years 7 months 9 days
Employee Stock Option [Member] | Minimum [Member]
Share-based payment award, fair value assumptions and methodology [Abstract]
Expected term (years)			3 months
Employee Stock Option [Member] | Maximum [Member]
Share-based payment award, fair value assumptions and methodology [Abstract]
Expected term (years)			6 years 4 months 24 days
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Registered shares (in shares)	500,000	500,000	500,000
Fair market value of the stock on the date of purchase (in hundredths)	85.00%	85.00%	85.00%
Employee stock purchase plan administrative expense	35	45	39
Other Stock Purchase Plan Shares Activity [Roll Forward]
Shares available for purchase, beginning of year (in shares)	339,166	370,400	407,102
Shares purchased under the plan (in shares)	(24,860)	(31,234)	(36,702)
Shares available for purchase, end of year (in shares)	314,306	339,166	370,400
Other stock purchase plan stock option exercise price range lower range limit (in dollars per share)	$ 24.93
Other stock purchase plan stock option exercise price range upper range limit (in dollars per share)	$ 30.32
Non-Employee Director Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair market value to purchase stock under Non-employee director stock option plan (in hundredths)	75.00%	75.00%	75.00%
Minimum cash retainer used to purchase common stock (in hundredths)	25.00%	25.00%	25.00%
Maximum cash retainer used to purchase common stock (in hundredths)	100.00%	100.00%	100.00%
Non employee director stock option plan administrative expense	$ 49	$ 36	$ 22
Other Stock Purchase Plan Shares Activity [Roll Forward]
Shares available for purchase, beginning of year (in shares)	196,165	149,404	155,467
Shares registered during period (in shares)	0	200,000	0
Shares deregistered during period (in shares)	0	(148,204)	0
Shares purchased under the plan (in shares)	(9,626)	(5,035)	(6,063)
Shares available for purchase, end of year (in shares)	186,539	196,165	149,404
Other stock purchase plan stock option exercise price range lower range limit (in dollars per share)	$ 21.56
Other stock purchase plan stock option exercise price range upper range limit (in dollars per share)	$ 24.31
Dividend Reinvestment Plan [Member]
Other Stock Purchase Plan Shares Activity [Roll Forward]
Shares available for purchase, beginning of year (in shares)	658,957	0	161,236
Shares registered during period (in shares)	0	661,185	0
Shares deregistered during period (in shares)	0	0	(161,185)
Shares purchased under the plan (in shares)	(4,139)	(2,228)	(51)
Shares available for purchase, end of year (in shares)	654,818	658,957	0
Other stock purchase plan stock option exercise price range lower range limit (in dollars per share)	$ 28.03	$ 28.11	$ 21.38
Other stock purchase plan stock option exercise price range upper range limit (in dollars per share)	$ 35.39	$ 31.47	$ 23.22
Employers Mutual Casualty Company Incentive Stock Option 1993 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deregistered shares (in shares)				105,120
Employers Mutual Casualty Company Incentive Stock Option 2003 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Registered shares (in shares)	1,500,000	1,500,000	1,500,000
Time limit for granting awards	10 years	10 years	10 years
Employers Mutual Casualty Company Stock Incentive 2007 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Registered shares (in shares)	2,000,000	2,000,000	2,000,000
Time limit for granting awards	10 years	10 years	10 years