Equity (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2020	Feb. 28, 2018	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Mar. 31, 2019
Equity
Cash dividend declared (in dollars per share)			$ 0.09		$ 0.18
Dividend paid					$ 8.6
Tax benefit							$ 16.7
Subsequent event
Equity
TRA payment	$ 14.2
Cactus Inc
Equity
Cash distributions to unit holders					8.0	$ 5.8
Cactus Inc | Subsequent event
Equity
Cash distributions to unit holders	14.2
CW Unit Holders other than Cactus, Inc.
Equity
Pro rata distributions to unit holders					$ 4.7	$ 3.8
CW Unit Holders other than Cactus, Inc. | Subsequent event
Equity
Pro rata distributions to unit holders	$ 8.3
Cactus LLC
Equity
Ownership interest					63.00%		62.80%
March 2019 Secondary Offering
Equity
Offering expenses								$ 1.0
Class A Common Stock
Equity
Common stock, shares outstanding (in shares)			47,478		47,478		47,159
Shares outstanding, percentage of total voting power					63.00%
Class A Common Stock | Cactus Inc
Equity
Common stock, shares outstanding (in shares)			47,500,000		47,500,000
Class A Common Stock | Cactus Wellhead LLC Agreement
Equity
CW Unit redemptions (in shares)		32,700,000	74,000	9,200,000	74,000	9,200,000
Class B Common Stock
Equity
Common stock, shares outstanding (in shares)			27,884		27,884		27,958
Shares outstanding, percentage of total voting power					37.00%
Class B Common Stock | Cactus Inc
Equity
Common stock, shares outstanding (in shares)			27,900,000		27,900,000