Equity Awards - Summary of Activity for Nonvested Restricted Shares (Detail) - Restricted Stock Units and Restricted Stock [Member] - $ / shares	12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Restricted Stock Units and Nonvested Restricted Stock at Beginning of Year	204,946	222,384	262,079
Number of Shares, Granted	66,741	97,257	111,230
Number of Shares, Vested	(77,588)	(111,695)	(147,678)
Number of Shares, Cancelled	0	(3,000)	(3,247)
Number of Shares, Restricted Stock Units and Nonvested Restricted Stock at End of Year	194,099	204,946	222,384
Weighted Average Grant Date Fair Value, Restricted Stock Units and Nonvested Restricted Stock at Beginning of Year	$ 121.12	$ 95.11	$ 84.66
Weighted Average Grant Date Fair Value, Granted	240.61	169.62	126.23
Weighted Average Grant Date Fair Value, Vested	152.66	124.78	104.33
Weighted Average Grant Date Fair Value, Cancelled	0	30.38	124.82
Weighted Average Grant Date Fair Value, Restricted Stock Units and Nonvested Restricted Stock at End of Year	$ 150.56	$ 121.12	$ 95.11