Principal Accounting Policies - Schedule Of Fair Value Measurement Inputs and Valuation Techniques (Detail) - Available for sale debt securities [Member]
Dec. 31, 2021
Ratio
Measurement Input, Cost to Sell [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Debt Securities, Available-for-sale, Measurement Input 9.96
Measurement Input, Discount Rate [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Debt Securities, Available-for-sale, Measurement Input 12
Measurement Input Probability of exit events [Member] | Liquidation Scenario [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Debt Securities, Available-for-sale, Measurement Input 20
Measurement Input Probability of exit events [Member] | Redemption Scenario [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Debt Securities, Available-for-sale, Measurement Input 40
Measurement Input Probability of exit events [Member] | IPO scenario [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Debt Securities, Available-for-sale, Measurement Input 40
Measurement Input Lack Of Marketability Discount [Member]  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Debt Securities, Available-for-sale, Measurement Input 22