EARNINGS PER SHARE ("EPS") (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Computation of Basic earnings per share:
Net income	$ 588,886	$ 404,459	$ 333,837
Weighted average common shares outstanding - basic (in shares)	114,602	113,096	113,176
Basic earnings per share (in dollars per share)	$ 5.14	$ 3.58	$ 2.95
Computation of Diluted earnings per share:
Net income	$ 588,886	$ 404,459	$ 333,837
Weighted average common shares outstanding - basic (in shares)	114,602	113,096	113,176
Add: dilutive effect of common stock equivalents (in shares)	1,142	1,040	2,022
Weighted average common shares outstanding—diluted (in shares)	115,744	114,136	115,198
Diluted earnings per share (in dollars per share)	$ 5.09	$ 3.54	$ 2.90