RESTRUCTURING CHARGES - Provisions, Respective Payments and Remaining Accrued Balance (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2018
Mar. 31, 2018
Mar. 31, 2019
Mar. 31, 2018
Mar. 31, 2017
Summarizes the provisions, respective payments, and remaining accrued balance          
Balance at the beginning of the period     $ 61,344 $ 23,501 $ 13,240
Provision for charges incurred $ 65,800 $ 82,700 99,005 66,845 38,758
Balance at the end of the period   61,344 32,434 61,344 23,501
Less: Current portion (classified as other current liabilities)     32,434    
Accrued restructuring costs, net of current portion (classified as other liabilities)     0    
Fiscal Year 2017          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred         49,395
Fiscal Year 2018          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred       90,691  
Grants in Fiscal Year 2019          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred     113,313    
Severance          
Summarizes the provisions, respective payments, and remaining accrued balance          
Balance at the beginning of the period     48,006 16,359 11,905
Balance at the end of the period   48,006 23,234 48,006 16,359
Less: Current portion (classified as other current liabilities)     23,234    
Accrued restructuring costs, net of current portion (classified as other liabilities)     0    
Severance | Fiscal Year 2017          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred         42,253
Severance | Fiscal Year 2018          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred       69,439  
Severance | Grants in Fiscal Year 2019          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred     38,634    
Long-Lived Asset Impairment          
Summarizes the provisions, respective payments, and remaining accrued balance          
Balance at the beginning of the period     0 0 0
Balance at the end of the period   0 0 0 0
Less: Current portion (classified as other current liabilities)     0    
Accrued restructuring costs, net of current portion (classified as other liabilities)     0    
Long-Lived Asset Impairment | Fiscal Year 2017          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred         0
Long-Lived Asset Impairment | Fiscal Year 2018          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred       9,417  
Long-Lived Asset Impairment | Grants in Fiscal Year 2019          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred     46,365    
Other Exit Costs          
Summarizes the provisions, respective payments, and remaining accrued balance          
Balance at the beginning of the period     13,338 7,142 1,335
Balance at the end of the period   $ 13,338 9,200 13,338 7,142
Less: Current portion (classified as other current liabilities)     9,200    
Accrued restructuring costs, net of current portion (classified as other liabilities)     0    
Other Exit Costs | Fiscal Year 2017          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred         7,142
Other Exit Costs | Fiscal Year 2018          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred       11,835  
Other Exit Costs | Grants in Fiscal Year 2019          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred     28,314    
Cash Charges          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred     78,600  
Cash Charges | Fiscal Year 2017          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred         (25,894)
Cash Charges | Fiscal Year 2016 and Prior          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred         (13,240)
Cash Charges | Fiscal Year 2018          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred       (24,555)  
Cash Charges | Fiscal Year 2017 and Prior          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred       (16,908)  
Cash Charges | Grants in Fiscal Year 2019          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred     (24,113)    
Cash Charges | Fiscal Year 2018 And Prior          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred     (44,916)    
Cash Charges | Severance | Fiscal Year 2017          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred         (25,894)
Cash Charges | Severance | Fiscal Year 2016 and Prior          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred         (11,905)
Cash Charges | Severance | Fiscal Year 2018          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred       (24,555)  
Cash Charges | Severance | Fiscal Year 2017 and Prior          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred       (13,237)  
Cash Charges | Severance | Grants in Fiscal Year 2019          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred     (22,783)    
Cash Charges | Severance | Fiscal Year 2018 And Prior          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred     (40,623)    
Cash Charges | Long-Lived Asset Impairment | Fiscal Year 2017          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred         0
Cash Charges | Long-Lived Asset Impairment | Fiscal Year 2016 and Prior          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred         0
Cash Charges | Long-Lived Asset Impairment | Fiscal Year 2018          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred       0  
Cash Charges | Long-Lived Asset Impairment | Fiscal Year 2017 and Prior          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred       0  
Cash Charges | Long-Lived Asset Impairment | Grants in Fiscal Year 2019          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred     0    
Cash Charges | Long-Lived Asset Impairment | Fiscal Year 2018 And Prior          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred     0    
Cash Charges | Other Exit Costs | Fiscal Year 2017          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred         0
Cash Charges | Other Exit Costs | Fiscal Year 2016 and Prior          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred         $ (1,335)
Cash Charges | Other Exit Costs | Fiscal Year 2018          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred       0  
Cash Charges | Other Exit Costs | Fiscal Year 2017 and Prior          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred       (3,671)  
Cash Charges | Other Exit Costs | Grants in Fiscal Year 2019          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred     (1,330)    
Cash Charges | Other Exit Costs | Fiscal Year 2018 And Prior          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred     (4,293)    
Non-Cash Charges          
Summarizes the provisions, respective payments, and remaining accrued balance          
Provision for charges incurred       12,100  
Non-Cash Charges | Fiscal Year 2018          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred     (73,194) (11,385)  
Non-Cash Charges | Severance | Fiscal Year 2018          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred     0 0  
Non-Cash Charges | Long-Lived Asset Impairment | Fiscal Year 2018          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred     (46,365) (9,417)  
Non-Cash Charges | Other Exit Costs | Fiscal Year 2018          
Summarizes the provisions, respective payments, and remaining accrued balance          
Cash payments for charges incurred     $ (26,829) $ (1,968)