Effect of changes in ownership interests on equity (Details) - USD ($) $ in Thousands	8 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Parent		$ 3,567	$ (8,903)
Stock Redeemed or Called During Period, Value	$ 0	0
Activity under employee stock purchase plan	143	325
Total effect of changes in ownership interest on equity attributable to Goosehead Insurance Inc.		2,524	$ (8,954)
Parent
Noncontrolling Interest [Line Items]
Stock Redeemed or Called During Period, Value	194	1,368
Activity under employee stock purchase plan	$ 143	$ 325