Net Income per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net income attributable to Liberty Oilfield Services Inc. Stockholders	$ (45,771)	$ 22,032	$ (44,051)	$ 40,153
Denominator, Basic [Abstract]
Basic weighted average shares outstanding (in shares)	83,292	68,404	82,472	67,918
Basic net income per share attributable to Liberty Oilfield Services Inc. Stockholders (in dollars per share)	$ (0.55)	$ 0.32	$ (0.53)	$ 0.59
Numerator, Diluted [Abstract]
Net income attributable to Liberty Oilfield Services Inc. Stockholders	$ (45,771)	$ 22,032	$ (44,051)	$ 40,153
Effect of exchange of the shares of Class B Common Stock for shares of Class A Common Stock	0	13,992	0	25,825
Net Income (Loss) Available to Common Stockholders, Diluted	$ (45,771)	$ 36,024	$ (44,051)	$ 65,978
Denominator, Diluted [Abstract]
Basic weighted average shares outstanding (in shares)	83,292	68,404	82,472	67,918
Effect of dilutive securities:
Restricted stock (in shares)	0	556	0	578
Restricted stock units (in shares)	0	1,808	0	1,717
Class B Common Stock (in shares)	0	43,570	0	44,064
Diluted weighted average shares outstanding (in shares)	83,292	114,338	82,472	114,277
Diluted net income per share attributable to Liberty Oilfield Services Inc. Stockholders (in dollars per share)	$ (0.55)	$ 0.32	$ (0.53)	$ 0.58