Subsequent events Tables (Details) | Apr. 25, 2018 | Mar. 31, 2018 | Mar. 31, 2017 |
Euro Term Loans [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | | 4.80 | 5.40 |
2018 Euro Term Loan [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | | 4.36% | |
2019 Euro Term Loan [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | | 4.19% | |
2021 Euro Term Loan [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | | 5 | |
Debt instrument, guarantee fee, stated percentage | | 4.22% | |
Net leverage greater than 7.0x [Member] | 2018 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 6.00% | | |
Net leverage greater than 7.0x [Member] | 2019 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 6.00% | | |
Net leverage greater than 7.0x [Member] | 2021 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 6.50% | | |
Net Leverage 7.0x - 6.0x [Member] | 2018 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 5.00% | | |
Net Leverage 7.0x - 6.0x [Member] | 2019 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 5.00% | | |
Net Leverage 7.0x - 6.0x [Member] | 2021 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 5.50% | | |
Net Leverage 6.0x - 5.0x [Member] | 2018 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 4.25% | | |
Net Leverage 6.0x - 5.0x [Member] | 2019 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 4.25% | | |
Net Leverage 6.0x - 5.0x [Member] | 2021 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 4.75% | | |
Net Leverage 5.0x - 4.0x [Member] | 2018 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 3.75% | | |
Net Leverage 5.0x - 4.0x [Member] | 2019 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 3.75% | | |
Net Leverage 5.0x - 4.0x [Member] | 2021 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 4.25% | | |
Net Leverage 4.0x - 3.0x [Member] | 2018 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 3.25% | | |
Net Leverage 4.0x - 3.0x [Member] | 2019 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 3.25% | | |
Net Leverage 4.0x - 3.0x [Member] | 2021 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 3.75% | | |
Net Leverage Less Than 3.0x [Member] | 2018 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 3.25% | | |
Net Leverage Less Than 3.0x [Member] | 2019 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 3.25% | | |
Net Leverage Less Than 3.0x [Member] | 2021 Euro Term Loan [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 3.50% | | |
Minimum [Member] | 2021 Revolving Credit Facility [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | | 5 | |
Minimum [Member] | Euro Term Loans [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, guarantee fee, stated percentage | 3.00% | | |
Minimum [Member] | Net leverage greater than 7.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 7 | | |
Minimum [Member] | Net leverage greater than 7.0x [Member] | Euro Term Loans [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | | 7 | |
Minimum [Member] | Net leverage greater than 7.0x [Member] | Euro Term Loans [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 7 | | |
Minimum [Member] | Net Leverage 7.0x - 6.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 6 | | |
Minimum [Member] | Net Leverage 7.0x - 6.0x [Member] | Euro Term Loans [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | | 6 | |
Minimum [Member] | Net Leverage 7.0x - 6.0x [Member] | Euro Term Loans [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 6 | | |
Minimum [Member] | Net Leverage 6.0x - 5.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 5 | | |
Minimum [Member] | Net Leverage 6.0x - 5.0x [Member] | Euro Term Loans [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | | 5 | |
Minimum [Member] | Net Leverage 6.0x - 5.0x [Member] | Euro Term Loans [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 5 | | |
Minimum [Member] | Net Leverage 5.0x - 4.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 4 | | |
Minimum [Member] | Net Leverage 5.0x - 4.0x [Member] | Euro Term Loans [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 4 | | |
Minimum [Member] | Net Leverage 4.0x - 3.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 3 | | |
Minimum [Member] | Net Leverage 4.0x - 3.0x [Member] | Euro Term Loans [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 3 | | |
Maximum [Member] | 2021 Revolving Credit Facility [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | | 7 | |
Maximum [Member] | Net Leverage 7.0x - 6.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 7 | | |
Maximum [Member] | Net Leverage 7.0x - 6.0x [Member] | Euro Term Loans [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | | 7 | |
Maximum [Member] | Net Leverage 7.0x - 6.0x [Member] | Euro Term Loans [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 7 | | |
Maximum [Member] | Net Leverage 6.0x - 5.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 6 | | |
Maximum [Member] | Net Leverage 6.0x - 5.0x [Member] | Euro Term Loans [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | | 6 | |
Maximum [Member] | Net Leverage 6.0x - 5.0x [Member] | Euro Term Loans [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 6 | | |
Maximum [Member] | Net Leverage 5.0x - 4.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 5 | | |
Maximum [Member] | Net Leverage 5.0x - 4.0x [Member] | Euro Term Loans [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 5 | | |
Maximum [Member] | Net Leverage 4.0x - 3.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 4 | | |
Maximum [Member] | Net Leverage 4.0x - 3.0x [Member] | Euro Term Loans [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 4 | | |
Maximum [Member] | Net Leverage Less Than 3.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 3 | | |
Maximum [Member] | Net Leverage Less Than 3.0x [Member] | Euro Term Loans [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Financial covenant, net leverage | 3 | | |
Alternative Base Rate [Member] | Net leverage greater than 7.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, interest rate, stated percentage | 5.25% | | |
Alternative Base Rate [Member] | Net Leverage 7.0x - 6.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, interest rate, stated percentage | 4.25% | | |
Alternative Base Rate [Member] | Net Leverage 6.0x - 5.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, interest rate, stated percentage | 3.50% | | |
Alternative Base Rate [Member] | Net Leverage 5.0x - 4.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, interest rate, stated percentage | 3.00% | | |
Alternative Base Rate [Member] | Net Leverage 4.0x - 3.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, interest rate, stated percentage | 2.50% | | |
Alternative Base Rate [Member] | Net Leverage Less Than 3.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, interest rate, stated percentage | 2.25% | | |
Eurodollar [Member] | Net leverage greater than 7.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, interest rate, stated percentage | 6.25% | | |
Eurodollar [Member] | Net Leverage 7.0x - 6.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, interest rate, stated percentage | 5.25% | | |
Eurodollar [Member] | Net Leverage 6.0x - 5.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, interest rate, stated percentage | 4.50% | | |
Eurodollar [Member] | Net Leverage 5.0x - 4.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, interest rate, stated percentage | 4.00% | | |
Eurodollar [Member] | Net Leverage 4.0x - 3.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, interest rate, stated percentage | 3.50% | | |
Eurodollar [Member] | Net Leverage Less Than 3.0x [Member] | 2021 Revolving Credit Facility [Member] | Subsequent Event [Member] | | | |
Subsequent Event [Line Items] | | | |
Debt instrument, interest rate, stated percentage | 3.25% | | |