Stock Repurchase Program - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	1 Months Ended			3 Months Ended				6 Months Ended
	Apr. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Apr. 30, 2021		Apr. 30, 2020	[2]	Apr. 30, 2021	Apr. 30, 2020	[2]	Jun. 19, 2020
Accelerated Share Repurchases [Line Items]
Stock repurchase program authorized amount											$ 500.0
Remaining amount available for further repurchases	$ 59.8			$ 59.8				$ 59.8
Purchases of treasury stock (in shares)				756	[1]	652		1,593	1,231
December 2020, ASR
Accelerated Share Repurchases [Line Items]
Stock repurchase program authorized amount			$ 250.0
Prepayment to repurchase stock			250.0
Initial share delivery			$ 200.0
Stock repurchase program, prepayment during prior period, future derivative settlement		$ 50.0
Purchases of treasury stock (in shares)			1,000
Purchases of treasury stock (in USD per share)			$ 252.36
April 2021, ASR
Accelerated Share Repurchases [Line Items]
Stock repurchase program authorized amount	$ 100.0			$ 100.0				$ 100.0
Purchases of treasury stock (in shares)	400
Purchases of treasury stock (in USD per share)	$ 253.54

[1] Includes the 166,276 shares and $50.0 million equity forward contract, respectively, from the December 2020 ASR.

[2] Does not include the 148,953 shares and $20.0 million equity forward contract, respectively, from the February 2020 ASR settled in May 2020.