Income Taxes - Effective income tax reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective income tax rate reconciliation
Income taxes at 21% (35% for 2017) statutory tax rate	$ 39,548	$ 35,658	$ 23,834
Statutory federal tax rate (as a percent)	21.00%	21.00%	35.00%
Profit of Cactus LL pre-IPO not subject to U.S. federal tax		$ (2,808)	$ (22,758)
Profit of non-controlling interest not subject to U.S. federal tax	$ (15,477)	(18,570)
Foreign income taxes (net of foreign tax credit)	364	828	(302)
State income taxes (excluding rate change)	4,887	2,746	594
Impact of change in forecasted state income tax rate	5,774
Foreign withholding taxes	988	1,056	220
Change in valuation allowance	(3,888)	733	(39)
Other	(176)	(123)
Total provision for income taxes	$ 32,020	$ 19,520	$ 1,549
Effective tax rate	17.00%	11.50%	2.30%