Description of Organization and Business Operations - Additional information (Detail) - USD ($)			9 Months Ended
	Jun. 21, 2021	Feb. 13, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Organization Business And Basis Of Presentation [Line Items]
Common stock price, per share			$ 10.00
Proceeds from issuance initial public offering		$ 276,000,000	$ 276,000,000	$ 276,000,000
Incurring offering cost		15,700,000
Payment of underwriting discount		$ 9,660,000	5,520,000
Cash			61,344		$ 981,606
Business combination, net tangible assets required to proceed			5,000,001
Business Combination, maximum amount of interest to pay dissolution expenses			$ 100,000
Business Combination required completion period after Initial Public Offering			24 months
Operating amount out of Trust account enough to operate for at least 12 months			$ 61,344
PIPE Investment [Member] | PIPE Subscription Agreement [Member] | Quanergy PubCo common stock [Member]
Organization Business And Basis Of Presentation [Line Items]
Issuance of Ordinary Share	4,000,000
Shares issued price per share	$ 10.00
Proceeds from issuance of common stock	$ 40,000,000
Quanergy Systems, Inc [Member] | Merger Agreement [Member]
Organization Business And Basis Of Presentation [Line Items]
Business combination, net tangible assets required to proceed	$ 5,000,001
Business acquisition equity interest issued or iisuable,number of shares issued	970,000,000
Share price	$ 10.00
Business Combination [Member]
Organization Business And Basis Of Presentation [Line Items]
Percentage of voting interests acquired			50.00%
Founder Shares [Member]
Organization Business And Basis Of Presentation [Line Items]
Proceed from issuance of shares			$ 25,000
Number of shares issued			300,000
Minimum [Member] | Quanergy Systems, Inc [Member] | PIPE Investment [Member] | Merger Agreement [Member]
Organization Business And Basis Of Presentation [Line Items]
Threshold proceeds net of redemptions for effecting a merger	$ 175,000,000
Class A Common Stock
Organization Business And Basis Of Presentation [Line Items]
Common stock par value			$ 0.0001		$ 0.0001
Class A Common Stock | Maximum [Member]
Organization Business And Basis Of Presentation [Line Items]
Percentage of aggregate Public Shares restricted from redeem			20.00%
IPO [Member]
Organization Business And Basis Of Presentation [Line Items]
Issuance of Ordinary Share		27,600,000
Common stock price, per share		$ 10.00
Proceeds from issuance initial public offering			$ 276,000,000
IPO [Member] | Over-Allotment Option [Member]
Organization Business And Basis Of Presentation [Line Items]
Issuance of Ordinary Share		3,600,000
IPO [Member] | Class A Common Stock
Organization Business And Basis Of Presentation [Line Items]
Issuance of Ordinary Share			34,500,000
Private Placement [Member]
Organization Business And Basis Of Presentation [Line Items]
Proceeds from issuance initial public offering		$ 7,520,000