Preparation of Interim Financial Statements and Other Items - Deferred tax components (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Components of deferred tax assets and liabilities
Investment in Cactus LLC	$ 179,265
Foreign loss carryforwards	383	$ 489
Deferred tax assets	179,648	489
Valuation allowance	(383)	(489)
Deferred tax asset, net	179,265
Foreign withholding taxes	1,094	416
Deferred tax liability, net	$ 1,094	$ 416