EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net income attributable to Franklin Electric Co., Inc.	$ 24,200	$ 30,000	$ 30,500	$ 21,200	$ 8,100	$ 24,500	$ 29,900	$ 15,700	$ 105,877	$ 78,180	$ 78,745
Less: Earnings allocated to participating securities									800	600	700
Less: Earnings allocated to redeemable noncontrolling interest									0	0	1,000
Net income available to common shareholders									$ 105,100	$ 77,600	$ 77,000
Denominator:
Basic weighted average common shares outstanding (in shares)									46.6	46.5	46.2
Effect of dilutive securities:
Non-participating employee stock options and performance awards (in shares)									0.4	0.5	0.5
Diluted weighted average common shares outstanding (in shares)									47.0	47.0	46.7
Basic earnings per share (in dollars per share)	$ 0.51	$ 0.64	$ 0.65	$ 0.45	$ 0.17	$ 0.52	$ 0.64	$ 0.33	$ 2.25	$ 1.67	$ 1.67
Diluted earnings per share (in dollars per share)	$ 0.51	$ 0.63	$ 0.64	$ 0.45	$ 0.17	$ 0.52	$ 0.64	$ 0.33	$ 2.23	$ 1.65	$ 1.65
Anti-dilutive stock options (in shares)									0.1	0.3	0.4