Derivative Instruments, Hedging Activities and Fair Value - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2022	Dec. 31, 2018	Feb. 28, 2018
Foreign Currency Derivatives
Liabilities		$ 1,807,231,000		$ 1,807,231,000			$ 1,319,491,000
Pre-tax net gains (losses) on certain loans designated as hedges of net investments in foreign subsidiaries		(3,000,000.0)	$ (800,000)	(3,700,000)	$ (7,500,000)
Repayment of Term Loan Facility	$ 2,800,000
Amount of gain or (loss) reclassified from accumulated other comprehensive income into income		(297,000)		2,068,000
Subject to Master Netting Agreements
Foreign Currency Derivatives
Liabilities		1,700,000		1,700,000			100,000
Foreign currency exchange forward contracts
Foreign Currency Derivatives
Notional amounts		464,400,000		464,400,000			423,900,000
Term Loan Facility, Fixed-Rate | Term Loan
Foreign Currency Derivatives
Principal amount		200,000,000.0		$ 200,000,000.0				$ 300,000,000.0
LIBOR | Term Loan Facility, Fixed-Rate | Term Loan
Foreign Currency Derivatives
Variable rate basis spread				2.12%
LIBOR | Scenario, Forecast | Term Loan Facility, Fixed-Rate | Term Loan
Foreign Currency Derivatives
Variable rate basis spread						3.12%
Income from discontinued businesses | Interest rate swaps
Foreign Currency Derivatives
Amount of gain or (loss) reclassified from accumulated other comprehensive income into income as a result that a forecasted transaction is no longer probable of occurring	2,700,000			$ 2,741,000
Amount of gain or (loss) reclassified from accumulated other comprehensive income into income		0		0
Floating-Rate To Fixed-Rate
Foreign Currency Derivatives
Converted debt	$ 100,000,000.0
Estimate of Fair Value Measurement
Foreign Currency Derivatives
Long-term debt		804,600,000		804,600,000			592,000,000.0
Reported Value Measurement
Foreign Currency Derivatives
Long-term debt		$ 784,200,000		$ 784,200,000			$ 605,400,000