Stock-Based Compensation Plans - Summarizes Transactions of SEUs (Detail) - Stock Equivalent Units [Member]	3 Months Ended
	Mar. 31, 2021 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, Number of SEUs, Beginning balance | shares	390,164
Granted at discount, Number of SEUs | shares	87,451
Granted at market value, Number of SEUs | shares	3,803
Exercised, Number of SEUs | shares	(6,275)
Forfeited, Number of SEUs | shares	(12,400)
Outstanding, Number of SEUs, Ending balance | shares	462,743
Outstanding, Weighted Average Exercise Price, Beginning balance	$ 4.35
Granted at discount, Weighted Average Exercise Price	0.00
Granted at market value, Weighted Average Exercise Price	99.85
Exercised, Weighted Average Exercise Price	1.36
Forfeited, Weighted Average Exercise Price	0.00
Outstanding, Weighted Average Exercise Price, Ending balance	4.47
Outstanding, Weighted Average Grant-Date Fair Value	63.96
Granted at discount, Weighted Average Grant-Date Fair Value	88.94
Granted at market value, Weighted Average Grant-Date Fair Value	32.71
Exercised, Weighted Average Grant-Date Fair Value	42.82
Forfeited, Weighted Average Grant-Date Fair Value	67.33
Outstanding, Weighted Average Grant-Date Fair Value	$ 68.62