Fair Value Measurement (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivative Financial Instruments, Liabilities | Interest rate derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, recurring basis	$ 0	$ (4,024)
Derivative Financial Instruments, Liabilities | Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, recurring basis	(605)	(8,802)
Derivative Financial Instruments, Assets | Interest rate derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	24,480	10,156
Derivative Financial Instruments, Assets | Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	3,806	405
Certificates of deposit (non-U.S.)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	39,640	12,809
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis		11,065
Corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	14	13
Money markets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	37	38
Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	86	79
Other Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	5,859	5,588
Level 1 | Derivative Financial Instruments, Liabilities | Interest rate derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, recurring basis	0	0
Level 1 | Derivative Financial Instruments, Liabilities | Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, recurring basis	0	0
Level 1 | Derivative Financial Instruments, Assets | Interest rate derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 1 | Derivative Financial Instruments, Assets | Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 1 | Certificates of deposit (non-U.S.)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 1 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis		0
Level 1 | Corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 1 | Money markets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	37	38
Level 1 | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	86	79
Level 1 | Other Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 2 | Derivative Financial Instruments, Liabilities | Interest rate derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, recurring basis	0	(4,024)
Level 2 | Derivative Financial Instruments, Liabilities | Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, recurring basis	(605)	(8,802)
Level 2 | Derivative Financial Instruments, Assets | Interest rate derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	24,480	10,156
Level 2 | Derivative Financial Instruments, Assets | Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	3,806	405
Level 2 | Certificates of deposit (non-U.S.)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	39,640	12,809
Level 2 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis		11,065
Level 2 | Corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	14	13
Level 2 | Money markets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 2 | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 2 | Other Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	5,859	5,588
Level 3 | Derivative Financial Instruments, Liabilities | Interest rate derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, recurring basis	0	0
Level 3 | Derivative Financial Instruments, Liabilities | Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, recurring basis	0	0
Level 3 | Derivative Financial Instruments, Assets | Interest rate derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 3 | Derivative Financial Instruments, Assets | Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 3 | Certificates of deposit (non-U.S.)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 3 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis		0
Level 3 | Corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 3 | Money markets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 3 | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	0	0
Level 3 | Other Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, recurring basis	$ 0	$ 0