Investments - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) Security	Dec. 31, 2021 USD ($)
Investments All Other Investments [Abstract]
Short-term investments with maturities less than one year	$ 292,000	$ 246,900
Short-term investments with maturities between one to three years	$ 154,200	180,400
Short-term investments maturities, description	As of March 31, 2022 and December 31, 2021, short-term investments of $292.0 million and $246.9 million, respectively, had maturities less than one year, and short-term investments of $154.2 million and $180.4 million, respectively, had maturities between one to three years.
Allowance for credit losses	$ 0	0
Available for sale securities gross unrealized loss positions for less than twelve months	$ 366,800
Number of available-for-sale securities | Security	36
Accrued interest receivable on available-for-sale securities	$ 1,600	$ 1,400