Quarterly Results (unaudited) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 343,302	$ 404,667	$ 447,684	$ 426,989	$ 305,195	$ 342,904	$ 400,569	$ 355,365	$ 1,622,642	$ 1,404,033	$ 1,310,254
Gross Profit	69,830	113,379	122,849	102,297	62,349	93,203	109,020	78,094	408,355	342,666	348,102
Earnings Before Income Taxes	79,442	105,072	109,671	129,927	43,607	56,157	98,367	57,564	424,112	255,695	283,778
Net Earnings from Continuing Operations	66,011	81,193	89,871	97,091	69,320	43,474	75,064	43,333
Net Earnings	$ 66,011	$ 81,193	$ 96,034	$ 96,206	$ 72,429	$ (114,632)	$ 71,793	$ 41,304	$ 339,444	$ 70,894	$ 68,860
Continuing Operations	$ 1.56	$ 1.94	$ 2.16	$ 2.34	$ 1.67	$ 1.04	$ 1.80	$ 0.98	$ 7.99	$ 5.47	$ 4.76
Diluted Earnings Per Share	$ 1.56	$ 1.94	$ 2.31	$ 2.31	$ 1.74	$ (2.76)	$ 1.72	$ 0.94	$ 8.12	$ 1.68	$ 1.47