Annual report pursuant to Section 13 and 15(d)

INCOME TAXES - Narrative (Details)

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INCOME TAXES - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Mar. 31, 2018
Mar. 31, 2017
Income Tax Disclosure [Abstract]        
Federal statutory rate (as a percent) 21.00%   31.50%  
Increase in balances related to tax positions in prior period $ 8,800      
Total unrecognized tax benefit including interest and penalties 108,400      
Unrecognized tax benefits that would impact efffective tax rate 90,100      
Accrued interest and penalties 1,100      
Income Tax Examination [Line Items]        
(Decrease) increase in valuation allowance (2,545) $ 10,311 $ (24,248)  
Unrecognized tax benefits 107,282 $ 116,032 $ 150,559 $ 170,730
Increase in unrecognized tax benefits is reasonably possible 9,100      
Federal net operating loss 334,200      
Tax credit carryforwards 67,600      
Federal net operating loss carryforwards attributable to excess tax deductions from stock option exercises 13,300      
Acquired net operating losses included in carryforwards 11,100      
Acquired credits included in carryforwards $ 8,400      
Minimum        
Income Tax Examination [Line Items]        
Open years 3 years      
Maximum        
Income Tax Examination [Line Items]        
Open years 5 years      
Other long-term assets        
Income Tax Examination [Line Items]        
Unrecognized tax benefits $ 102,300      
Other long-term liabilities        
Income Tax Examination [Line Items]        
Unrecognized tax benefits $ 6,100