Stock-Based Compensation and Stock Options - Stock Options Outstanding and Exercisable (Detail) - $ / shares	6 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Outstanding Options	706,728	722,343	723,876	778,982	846,625	937,158
Weighted Average Remaining Contractual Life	3 years 4 months 6 days
Outstanding Options – Weighted Average Exercise Price	$ 96.14	$ 90.94	$ 84.55	$ 72.17	$ 68.50	$ 64.28
Exercisable Options – Number of Exercisable Options	335,484
Exercisable Options – Weighted Average Exercise Price	$ 68.00
Range of Exercise Price, $33.16 to $59.32 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, lower limit	33.16
Range of Exercise Price, upper limit	$ 59.32
Number of Outstanding Options	182,608
Weighted Average Remaining Contractual Life	2 years 4 months 17 days
Outstanding Options – Weighted Average Exercise Price	$ 49.94
Exercisable Options – Number of Exercisable Options	166,104
Exercisable Options – Weighted Average Exercise Price	$ 49.64
Range of Exercise Price, $59.33 to 87.49 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, lower limit	59.33
Range of Exercise Price, upper limit	$ 87.49
Number of Outstanding Options	184,114
Weighted Average Remaining Contractual Life	2 years 10 months 17 days
Outstanding Options – Weighted Average Exercise Price	$ 78.00
Exercisable Options – Number of Exercisable Options	109,556
Exercisable Options – Weighted Average Exercise Price	$ 77.59
Range of Exercise Price, $87.50 to $148.89 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, lower limit	87.50
Range of Exercise Price, upper limit	$ 148.89
Number of Outstanding Options	212,914
Weighted Average Remaining Contractual Life	3 years 4 months 28 days
Outstanding Options – Weighted Average Exercise Price	$ 105.95
Exercisable Options – Number of Exercisable Options	52,901
Exercisable Options – Weighted Average Exercise Price	$ 94.41
Range of Exercise Price, $148.90 to $197.16 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, lower limit	148.90
Range of Exercise Price, upper limit	$ 197.16
Number of Outstanding Options	127,092
Weighted Average Remaining Contractual Life	5 years 4 months 6 days
Outstanding Options – Weighted Average Exercise Price	$ 172.35
Exercisable Options – Number of Exercisable Options	6,923
Exercisable Options – Weighted Average Exercise Price	$ 155.00