SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net Sales	$ 320,100	$ 348,400	$ 355,400	$ 290,700	$ 316,600	$ 341,900	$ 344,000	$ 295,600	$ 1,314,578	$ 1,298,129	$ 1,124,909
Gross Profit	101,300	117,600	119,700	89,500	104,300	113,000	116,100	99,000	428,103	432,366	376,982
Net income	20,000	34,100	32,800	9,100	24,300	30,000	30,000	21,200	95,999	105,517	78,593
Net Income Attributable to Franklin Electric Co., Inc.	$ 19,800	$ 33,900	$ 32,700	$ 9,100	$ 24,200	$ 30,000	$ 30,500	$ 21,200	$ 95,483	$ 105,877	$ 78,180
Basic Earnings Per Share (in dollars per share)	$ 0.42	$ 0.73	$ 0.70	$ 0.19	$ 0.51	$ 0.64	$ 0.65	$ 0.45	$ 2.04	$ 2.25	$ 1.67
Diluted Earnings Per Share (in dollars per share)	$ 0.42	$ 0.72	$ 0.70	$ 0.19	$ 0.51	$ 0.63	$ 0.64	$ 0.45	$ 2.03	$ 2.23	$ 1.65