Long-term debt Schedule of Derivative Instruments (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Interest Rate Cap Agreements Effective June 29, 2018
Derivative [Line Items]
Derivative, effective date	Jun. 29, 2018
Derivative, expiration date	Jun. 30, 2020
Interest Rate Cap Agreements Effective June 30, 2020
Derivative [Line Items]
Derivative, effective date	Jun. 30, 2020
Derivative, expiration date	Jun. 30, 2024
Term Loan Facility | Interest Rate Cap Agreements Effective June 29, 2018 | Maximum
Derivative [Line Items]
Notional amounts of interest rate agreements	$ 3,500,000,000
LIBOR plus interest rate margin	3.50%
Term Loan Facility | Interest Rate Cap Agreements Effective June 30, 2020 | Maximum
Derivative [Line Items]
Notional amounts of interest rate agreements	$ 3,500,000,000
LIBOR plus interest rate margin	2.00%
Cash Flow Hedging
Derivative [Line Items]
Amount of debt expense reclassified from accumulated OCI into income	$ 1,623,000	$ 1,606,000
Amount of unrecognized losses in OCI on interest rate cap agreements	(13,018,000)	$ (580,000)
Debt Expense | Cash Flow Hedging | Interest Rate Cap Agreements Effective June 29, 2018
Derivative [Line Items]
Amount of debt expense reclassified from accumulated OCI into income	2,163,000
Amount of unrecognized losses in OCI on interest rate cap agreements	0
Debt Expense | Cash Flow Hedging | Interest Rate Cap Agreements Effective June 30, 2020
Derivative [Line Items]
Amount of unrecognized losses in OCI on interest rate cap agreements	17,346,000
Other Long-term Assets | Interest Rate Cap Agreements Effective June 29, 2018
Derivative [Line Items]
Derivative asset, fair value, gross asset	0		$ 0
Other Long-term Assets | Interest Rate Cap Agreements Effective June 30, 2020
Derivative [Line Items]
Derivative asset, fair value, gross asset	$ 7,106,000		$ 24,452,000