Restatement of Previously Issued Financial Statements - Summary of Basic and Diluted Earnings Per Common Share (Detail) - $ / shares	1 Months Ended	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021	Sep. 30, 2021
Class A Ordinary Shares [Member]
Error Corrections And Prior Period Adjustments Of Financial Statement Restatement [Line Items]
Basic and diluted loss per share	$ 0.00	$ 0.79				$ 1.34
Class A Ordinary Shares [Member] \| As Previously Reported [Member]
Error Corrections And Prior Period Adjustments Of Financial Statement Restatement [Line Items]
Basic earnings per share				$ 0.00
Diluted weighted average shares outstanding				59,091,350
Diluted earnings per share				$ 0.00
Basic and diluted loss per share			$ 0.00		$ 0.00
Class A Ordinary Shares [Member] \| Adjustment [Member]
Error Corrections And Prior Period Adjustments Of Financial Statement Restatement [Line Items]
Basic earnings per share				$ 0.69
Diluted weighted average shares outstanding				(9,091,350)
Diluted earnings per share				$ 0.69
Basic and diluted loss per share			(0.14)		0.55
Class A Ordinary Shares [Member] \| As Restated [Member]
Error Corrections And Prior Period Adjustments Of Financial Statement Restatement [Line Items]
Basic earnings per share				$ 0.69
Diluted weighted average shares outstanding				50,000,000
Diluted earnings per share				$ 0.69
Basic and diluted loss per share			(0.14)		0.55
Class B Ordinary Shares [Member]
Error Corrections And Prior Period Adjustments Of Financial Statement Restatement [Line Items]
Basic and diluted loss per share	$ 0.00	$ 0.79				$ 1.34
Class B Ordinary Shares [Member] \| As Previously Reported [Member]
Error Corrections And Prior Period Adjustments Of Financial Statement Restatement [Line Items]
Basic and diluted loss per share			(0.71)	3.45	2.74
Class B Ordinary Shares [Member] \| Adjustment [Member]
Error Corrections And Prior Period Adjustments Of Financial Statement Restatement [Line Items]
Basic and diluted loss per share			0.57	(2.76)	(2.19)
Class B Ordinary Shares [Member] \| As Restated [Member]
Error Corrections And Prior Period Adjustments Of Financial Statement Restatement [Line Items]
Basic and diluted loss per share			$ (0.14)	$ 0.69	$ 0.55

Altimeter Growth Corp. 10-Q/A