Borrowings - Narrative (Details) € in Millions | Jul. 14, 2020USD ($) | Feb. 25, 2020USD ($) | Sep. 30, 2021USD ($) | Sep. 30, 2020USD ($) | Mar. 31, 2020USD ($) | Sep. 30, 2021USD ($) | Sep. 30, 2020USD ($) | Dec. 31, 2020USD ($) | Feb. 25, 2020EUR (€) | Jun. 16, 2016USD ($) |
Debt Instrument [Line Items] | | | | | | | | | | |
Unrealized loss (gain) on remeasurement of debt | | | $ (12,800,000) | $ 34,700,000 | | $ (31,320,000) | $ 37,400,000 | | | |
Loss on debt refinancing | | | 0 | 1,299,000 | | 0 | 37,400,000 | | | |
Amortization of debt issuance costs | | | | | | 4,376,000 | 4,774,000 | | | |
Payment of debt issuance costs | | | | | | 0 | $ 32,211,000 | | | |
Long-term debt | | | $ 2,756,561,000 | | | $ 2,756,561,000 | | $ 2,801,587,000 | | |
Debt instrument, covenant, maximum net leverage ratio, percent of principal in excess of revolving loan commitments | | | 30.00% | | | 30.00% | | | | |
Debt instrument, covenant, maximum net leverage ratio, aggregate principal amount of letter of credit obligations (more than) | | | $ 10,000,000 | | | $ 10,000,000 | | | | |
Medium-term Notes | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Long-term debt, fair value | | | 2,787,300,000 | | | $ 2,787,300,000 | | 2,830,500,000 | | |
Debt Instrument, springing maturity date, days prior to maturity date of the Second Lien Term Facility | | | | | | 91 days | | | | |
Debt instrument, springing maturity date, amount of the Second Lien Term Loan not repaid or extended (more than) | | | | | | $ 100,000,000 | | | | |
Medium-term Notes | London Interbank Offered Rate (LIBOR) Swap Rate | Minimum | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, basis spread on variable rate | | | | | | 0.00% | | | | |
Senior Notes | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument redemption, fee | | | | | $ 11,600,000 | | | | | |
Line of Credit | Revolving Credit Facility | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Extinguishment of debt, amount | $ 45,000,000 | | | | | | | | | |
Long-term debt | | | 0 | | | $ 0 | | 0 | | |
Line of Credit | Letter of Credit | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Long-term debt | | | $ 1,400,000 | | | $ 1,400,000 | | $ 1,400,000 | | |
Line of Credit | Minimum | Revolving Credit Facility | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Line of credit facility, unused capacity, commitment fee percentage | | | | | | 0.375% | | | | |
Line of Credit | Maximum | Revolving Credit Facility | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Line of credit facility, unused capacity, commitment fee percentage | | | | | | 0.50% | | | | |
Line of Credit | London Interbank Offered Rate (LIBOR) Swap Rate | Minimum | Revolving Credit Facility | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, basis spread on variable rate | | | | | | 3.00% | | | | |
Line of Credit | London Interbank Offered Rate (LIBOR) Swap Rate | Maximum | Revolving Credit Facility | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, basis spread on variable rate | | | | | | 3.25% | | | | |
Line of Credit | Base Rate | Minimum | Revolving Credit Facility | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, basis spread on variable rate | | | | | | 2.00% | | | | |
Line of Credit | Base Rate | Maximum | Revolving Credit Facility | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, basis spread on variable rate | | | | | | 2.25% | | | | |
Senior Secured Notes | Senior Notes | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, face amount | | | | | | | | | | $ 650,000,000 |
Debt instrument, interest rate, stated percentage | | | | | | | | | | 7.125% |
Loss on debt refinancing | | | | | 13,300,000 | | | | | |
First Lien Term Facilities | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Amortization of debt issuance costs | | | | | 11,300,000 | | | | | |
Payment of debt issuance costs | | $ 2,100,000 | | | 10,700,000 | | | | | |
Amortization of debt issuance costs and discounts | | 9,000,000 | | | $ 600,000 | | | | | |
Debt instrument, previously deferred debt issuance costs | | 18,400,000 | | | | | | | | |
Debt instrument, original issue discount | | 18,400,000 | | | | | | | | |
Debt instrument, covenant, maximum net leverage | | | 0.0625 | | | 0.0625 | | | | |
Debt instrument, debt default, principal, additional interest rate | | | | | | 2.00% | | | | |
First Lien Term Facilities | Fed Funds Effective Rate Overnight Index Swap Rate | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, basis spread on variable rate | | | | | | 0.005% | | | | |
First Lien Term Facilities | Medium-term Notes | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, quarterly installment, percentage of original principal amount | | | 0.25% | | | 0.25% | | | | |
Line of credit facility, maximum borrowing capacity | | | $ 392,000,000 | | | $ 392,000,000 | | | | |
Line of credit facility, maximum borrowing capacity, percentage of LTM EBITDA | | | 100.00% | | | 100.00% | | | | |
First Lien Term Facilities | Medium-term Notes | London Interbank Offered Rate (LIBOR) Swap Rate | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, basis spread on variable rate | | | | | | 1.00% | | | | |
First Lien Term Facilities | Medium-term Notes | Base Rate | Minimum | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, basis spread on variable rate | | | | | | 0.00% | | | | |
First Lien Term Facilities | Line of Credit | Letter of Credit | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Line of credit facility, maximum borrowing capacity | | | $ 30,000,000 | | | $ 30,000,000 | | | | |
First Lien Term Facilities | Line of Credit | Bridge Loan | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Line of credit facility, maximum borrowing capacity | | | $ 15,000,000 | | | $ 15,000,000 | | | | |
Dollar Term Loan | Medium-term Notes | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, face amount | | 1,790,000,000 | | | | | | | | |
Debt instrument, interest rate, stated percentage | | | 3.335% | | | 3.335% | | 3.397% | | |
Debt instrument, original issue discount percentage | | | 0.50% | | | 0.50% | | 0.50% | | |
Debt instrument, subsequent issue discount percentage | | | 0.125% | | | 0.125% | | 0.125% | | |
Dollar Term Loan | Medium-term Notes | London Interbank Offered Rate (LIBOR) Swap Rate | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, basis spread on variable rate | | | | | | 3.25% | | | | |
Dollar Term Loan | Medium-term Notes | Base Rate | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, basis spread on variable rate | | | | | | 2.25% | | | | |
Euro Term Loan | Medium-term Notes | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, face amount | € | | | | | | | | | € 480 | |
Debt instrument, interest rate, stated percentage | | | 3.25% | | | 3.25% | | 3.25% | | |
Debt instrument, original issue discount percentage | | | 0.00% | | | 0.00% | | 0.00% | | |
Euro Term Loan | Medium-term Notes | London Interbank Offered Rate (LIBOR) Swap Rate | Minimum | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, basis spread on variable rate | | | | | | 3.25% | | | | |
Euro Term Loan | Medium-term Notes | London Interbank Offered Rate (LIBOR) Swap Rate | Maximum | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, basis spread on variable rate | | | | | | 3.50% | | | | |
Second Lien Term Facilities | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Payment of debt issuance costs | | 6,000,000 | | | | | | | | |
Amortization of debt issuance costs and discounts | | 2,100,000 | | | | | | | | |
Second Lien Term Facilities | Medium-term Notes | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt instrument, face amount | 50,000,000 | $ 425,000,000 | | | | | | | | |
Debt instrument, interest rate, stated percentage | | | 7.125% | | | 7.125% | | | | |
Amortization of debt issuance costs | | | | $ 1,300,000 | | | | | | |
Debt instrument, previously deferred debt issuance costs | 5,600,000 | | | | | | | | | |
Debt instrument, original issue discount | 2,000,000 | | | | | | | | | |
Debt instrument, subsequent issue discount | $ 100,000 | | | | | | | | | |
Debt instrument, prepayment premium after February 25, 2021 but on or prior to February 25, 2022, percent | | | | | | 2.00% | | | | |
Debt instrument, prepayment premium after February 25, 2022 but on or prior to February 25, 2023, percent | | | | | | 1.00% | | | | |
Debt instrument, prepayment premium after February 25, 2023, percent | | | | | | 0.00% | | | | |
Line of credit facility, maximum borrowing capacity | | | $ 490,000,000 | | | $ 490,000,000 | | | | |
Line of credit facility, maximum borrowing capacity, percentage of LTM EBITDA | | | 125.00% | | | 125.00% | | | | |