Net Income (Loss) Per Share - Summary of Dilutive Effect for Awards with Exercise Price Less than Average Stock Price (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net income from continuing operations	$ 3,480	$ 5,645	$ 34,190	$ 25,934
Net income attributable to noncontrolling interests	(176)	(115)	(302)	(259)
Income from continuing operations attributable to Blucora, Inc.	3,304	5,530	33,888	25,675
Loss from discontinued operations attributable to Blucora, Inc.	0	(19,975)	0	(17,453)
Net income (loss) attributable to Blucora, Inc.	$ 3,304	$ (14,445)	$ 33,888	$ 8,222
Weighted average common shares outstanding, basic	43,644	41,405	42,895	41,288
Dilutive potential common shares	3,293	893	3,287	666
Weighted average common shares outstanding, diluted	46,937	42,298	46,182	41,954
Earnings Per Share, Basic [Abstract]
Continuing operations, basic (in USD per share)	$ 0.08	$ 0.13	$ 0.79	$ 0.62
Discontinued operations, basic (in USD per share)	0.00	(0.48)	0.00	(0.42)
Basic (in USD per share)	0.08	(0.35)	0.79	0.20
Earnings Per Share, Diluted [Abstract]
Continuing operations, diluted (in USD per share)	0.07	0.13	0.73	0.61
Discontinued operations, diluted (in USD per share)	0.00	(0.47)	0.00	(0.41)
Diluted (in USD per share)	$ 0.07	$ (0.34)	$ 0.73	$ 0.20
Shares excluded	664	7,524	1,363	7,648