Net Income per Share - Numerators and Denominators of the Basic and Diluted EPS Computations for Common Stock (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Weighted average shares used in computing net income per share, basic (in shares)	154,514	152,444
Net income per share, basic (in usd per share)	$ 0.65	$ 0.76
Reallocation as a result of conversion of Class B to Class A common stock:
Weighted average shares used in computing net income per share, diluted (in shares)	161,928	162,213
Net income per share, diluted (in usd per share)	$ 0.62	$ 0.71
Class A common stock
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Net income, basic	$ 90,548	$ 104,319
Weighted average shares used in computing net income per share, basic (in shares)	139,749	137,607
Net income per share, basic (in usd per share)	$ 0.65	$ 0.76
Reallocation as a result of conversion of Class B to Class A common stock:
Net income, basic	$ 9,567	$ 11,248
Reallocation of net income to Class B common stock	0	0
Net income, diluted	$ 100,115	$ 115,567
Conversion of Class B to Class A common stock (in shares)	14,765	14,837
Effect of potentially dilutive common shares (in shares)	7,414	9,769
Weighted average shares used in computing net income per share, diluted (in shares)	161,928	162,213
Net income per share, diluted (in usd per share)	$ 0.62	$ 0.71
Class B common stock
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Net income, basic	$ 9,567	$ 11,248
Weighted average shares used in computing net income per share, basic (in shares)	14,765	14,837
Net income per share, basic (in usd per share)	$ 0.65	$ 0.76
Reallocation as a result of conversion of Class B to Class A common stock:
Net income, basic	$ 0	$ 0
Reallocation of net income to Class B common stock	4,146	6,282
Net income, diluted	$ 13,713	$ 17,530
Conversion of Class B to Class A common stock (in shares)	0	0
Effect of potentially dilutive common shares (in shares)	7,414	9,769
Weighted average shares used in computing net income per share, diluted (in shares)	22,179	24,606
Net income per share, diluted (in usd per share)	$ 0.62	$ 0.71