Annual report pursuant to Section 13 and 15(d)

Debt Debt - Customer Advances (Details)

v3.19.1
Debt Debt - Customer Advances (Details) - USD ($)
$ in Thousands
12 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Mar. 31, 2017
Debt Instrument [Line Items]      
Capital expenditures $ (146,056) $ (65,004) $ (25,617)
Restricted Cash 0 $ 0 $ 0
Advanced Payment from Customer      
Debt Instrument [Line Items]      
Proceeds from issuance of debt 13,400    
Capital expenditures (16,300)    
Line of Credit | Advanced Payment from Customer      
Debt Instrument [Line Items]      
Maximum borrowing capacity 72,000    
Line of Credit | Advanced Payment from Customer | Maximum      
Debt Instrument [Line Items]      
Repayments of debt 1,800    
Prepaid Expenses and Other Current Assets      
Debt Instrument [Line Items]      
Restricted Cash $ 0