Net Loss Per Share - Basic and Diluted Net Income (Loss) per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
LendingClub net loss	$ (22,804)	$ (6,530)	$ (114,846)	$ (61,828)
Weighted-average common shares - Basic (shares)	424,359,142	412,778,995	421,306,508	406,633,850
Weighted-average common shares - Diluted (shares)	424,359,142	412,778,995	421,306,508	406,633,850
Net loss per share attributable to LendingClub:
Basic ($ per share)	$ (0.05)	$ (0.02)	$ (0.27)	$ (0.15)
Diluted ($ per share)	$ (0.05)	$ (0.02)	$ (0.27)	$ (0.15)