RECENT ACCOUNTING PRONOUNCEMENTS - Cumulative Effect of Adoption of Topic 606 on Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Apr. 01, 2018	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net	$ 337,671	$ 167,109	$ 152,888
Other current assets	50,488		18,588
Total current assets	781,146	913,947	899,726
Deferred tax assets	26,508	19,041	17,950
Total assets	3,116,535	1,090,615	1,076,887
Accrued liabilities	398,715	91,230	80,097
Total current liabilities	528,229	136,647	125,514
Other long-term liabilities	142,697		18,566
Total liabilities	2,394,848	735,050	723,917
Retained earnings	143,344	301,661	299,066
Total stockholders' equity before treasury stock	1,575,360	1,181,992	1,179,397
Total stockholders' equity	721,687	355,565	352,970	$ 382,156	$ 312,399
Total liabilities and stockholders' equity	3,116,535	$ 1,090,615	1,076,887
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net	241,648
Other current assets	49,675
Total current assets	684,310
Deferred tax assets	23,911
Total assets	3,017,102
Accrued liabilities	314,153
Total current liabilities	443,667
Other long-term liabilities	141,894
Total liabilities	2,309,483
Retained earnings	129,276
Total stockholders' equity before treasury stock	1,561,292
Total stockholders' equity	707,619
Total liabilities and stockholders' equity	3,017,102
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net	(96,023)		14,221
Other current assets	(813)
Total current assets	(96,836)		14,221
Deferred tax assets	(2,597)		(493)
Total assets	(99,433)		13,728
Accrued liabilities	(84,562)		11,133
Total current liabilities	(84,562)		11,133
Other long-term liabilities	(803)
Total liabilities	(85,365)		11,133
Retained earnings	(14,068)		2,595
Total stockholders' equity before treasury stock	(14,068)		2,595
Total stockholders' equity	(14,068)		2,595
Total liabilities and stockholders' equity	$ (99,433)		$ 13,728