Equity (Details) - USD ($)					3 Months Ended			9 Months Ended		12 Months Ended	44 Months Ended
	Sep. 13, 2021	Jun. 17, 2021	Mar. 12, 2021	Mar. 09, 2021	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Sep. 30, 2021
Equity
Effect of CW Unit redemptions					$ 0		$ 0	$ 0	$ 0
TRA Liability Increase					7,500,000	$ 33,100,000
Tax expense (benefit)					$ 3,290,000		$ 23,000	$ 586,000	$ 8,833,000
Cash dividend declared (in dollars per share)					$ 0.10		$ 0.09	$ 0.28	$ 0.27
Cash dividends paid								$ 15,249,000	$ 12,847,000
Additional Paid-In Capital
Equity
Effect of CW Unit redemptions					$ (6,743,000)	(26,900,000)	$ (476,000)	(78,654,000)	(1,015,000)
Non-controlling Interest
Equity
Effect of CW Unit redemptions					6,752,000	26,900,000	$ 476,000	78,763,000	1,016,000
Restricted Stock
Equity
Dividends paid								$ 200,000	0
Cactus LLC
Equity
Ownership interest								77.90%		63.30%
Cactus Inc
Equity
Cash distributions to unit holders								$ 24,700,000	26,500,000
CW Unit Holders other than Cactus, Inc.
Equity
Pro rata distributions made to other members								$ 8,100,000	15,600,000
CW Unit Holders other than Cactus, Inc. | Cactus LLC
Equity
CW Unit redemptions (in shares)	715,215	3,300,000
Common Units transferred (in shares)	228,878	944,093
Proceeds from issuance of common stock		$ 0
Cactus Wellhead LLC Agreement | Additional Paid-In Capital
Equity
Effect of CW Unit redemptions					(6,800,000)
Cactus Wellhead LLC Agreement | Non-controlling Interest
Equity
Effect of CW Unit redemptions					$ 6,800,000
March 2021 Secondary Offering
Equity
TRA Liability Increase			$ 46,700,000
March 2021 Secondary Offering | Additional Paid-In Capital
Equity
Effect of CW Unit redemptions			(45,000,000)
March 2021 Secondary Offering | Non-controlling Interest
Equity
Effect of CW Unit redemptions			45,000,000
March 2021 Secondary Offering | Partial Valuation Allowance Release From Redemption Of Units
Equity
Tax expense (benefit)			(5,100,000)
March 2021 Secondary Offering | Other Nonoperating Income (Expense)
Equity
Proceeds from issuance of common stock			0
Offering expenses			$ 400,000
Class A Common Stock
Equity
Common stock, shares outstanding (in shares)					58,947,000			58,947,000		47,713,000	58,947,000
Shares outstanding, percentage of total voting power					77.90%			77.90%			77.90%
Dividends declared								$ 15,300,000	13,000,000
Cash dividends paid								$ 15,200,000	$ 12,800,000
Class A Common Stock | CW Unit Holders other than Cactus, Inc. | Cactus LLC
Equity
Shares issued (in shares)	715,215	3,300,000
Tax expense (benefit)					$ (700,000)	$ (3,000,000)
Class A Common Stock | Cactus Wellhead LLC Agreement
Equity
CW Unit redemptions (in shares)					192,459	425,433	67,702		142,115		43,800,000
Class A Common Stock | March 2021 Secondary Offering
Equity
CW Unit redemptions (in shares)			6,272,500
Shares issued (in shares)				6,325,000
Price of stock (in dollars per share)				$ 30.555
Other shares sold (in shares)			52,500
Class A Common Stock | Underwriter option
Equity
Shares granted in secondary offering (in shares)				825,000
Class B Common Stock
Equity
Common stock, shares outstanding (in shares)					16,757,000			16,757,000		27,655,000	16,757,000
Shares outstanding, percentage of total voting power					22.10%			22.10%			22.10%