Earnings (Loss) per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Numerator:
Net (loss) income	$ (13,752)	$ (8,796)	$ 5,918	$ 2,326	$ (5,256)	$ 3,902	$ 5,398	$ (3,957)	$ (14,302)	$ 87	$ 7,817
Net (loss) income attributable to non-controlling interest									(2,849)	869	11,310
Net (loss) income attributable to PetIQ, Inc.									$ (11,453)	$ (782)	$ (3,493)
Denominator:
Basic weighted average shares (in shares)	23,436	22,974	22,365	21,800	21,283	16,944	15,980	14,575	22,652	17,216	13,223
Weighted-average shares of Class A common stock outstanding - diluted (in shares)	23,436	22,974	22,597	21,978	21,283	17,239	16,008	14,575	22,652	17,216	13,223
Basic net income (loss) per common share	$ (0.47)	$ (0.26)	$ 0.17	$ 0.07	$ (0.16)	$ 0.13	$ 0.16	$ (0.14)	$ (0.51)	$ (0.05)	$ (0.26)
Diluted net (loss) income per common share	$ (0.47)	$ (0.26)	$ 0.17	$ 0.07	$ (0.16)	$ 0.13	$ 0.16	$ (0.14)	$ (0.51)	$ (0.05)	$ (0.26)