Treasury Stock - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Mar. 31, 2023	Nov. 30, 2022
Class of Stock [Line Items]
Number of shares of common stock authorized to repurchase	39,000,000		39,000,000			1,000,000
Treasury stock, value	$ 775,400,000		$ 775,400,000		$ 748,195,000
Treasury stock, shares	37,951,359		37,951,359		37,817,866
Average price per share of common stock	$ 206.99		$ 203.8
Common stock, shares outstanding	17,119,483		17,119,483		17,169,500
Purchase of treasury stock, shares	45,501
Purchase of treasury stock	$ (9,418,000)	$ (25,598,000)	$ (27,205,000)	$ (52,286,000)
Common Stock [Member]
Class of Stock [Line Items]
Purchase of treasury stock, shares	0	0	0	0
Purchase of treasury stock	$ 0	$ 0	$ 0	$ 0
1996 Repurchase Program [Member]
Class of Stock [Line Items]
Treasury stock, shares	37,951,359		37,951,359
Common stock equals to percentage of outstanding common stock			69.00%
Average price per share of common stock			$ 20.43
Common stock, shares outstanding	17,119,483		17,119,483
Purchase of treasury stock, shares	16,498
Treasury stock, shares outstanding	37,951,359		37,951,359
1996 Repurchase Program [Member] | Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares outstanding	133,493		133,493