Preparation of Interim Financial Statements and Other Items - Effective Income Tax (Details)1 - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Effective income tax rate reconciliation
Statutory tax rate (as a percent)			21.00%
Income taxes at 21% statutory tax rate	$ 10,891		$ 26,494
Profit of Cactus LL pre-IPO not subject to U.S. federal tax			(2,808)
Profit of non-controlling interest not subject to U.S. federal tax	(4,979)		(13,185)
Foreign earnings subject to different tax rates	(298)		(122)
State income taxes	1,511		2,527
Foreign withholding taxes	382		678
Change in valuation allowance	(104)		(106)
Other	812		1,086
Total provision for income taxes	$ 8,215	$ 479	$ 14,564	$ 942