Fair Value Measurement - Fair Values of Our Derivative Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative equity	$ 515	$ 0	$ 193	$ 0
Accrued liabilities	1,000		1,000
Foreign exchange contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative equity			303		$ 496
Recurring | Foreign exchange contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	303		303		496
Derivative equity			303		496
Recurring | Foreign exchange contract | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0		0
Derivative equity			0		0
Recurring | Foreign exchange contract | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	303		303		496
Derivative equity			303		496
Recurring | Foreign exchange contract | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0		0
Derivative equity			0		0
Recurring | Interest swap contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	353		353		1,131
Derivative liabilities	1,318		1,318		0
Recurring | Interest swap contract | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0		0
Derivative liabilities	0		0		0
Recurring | Interest swap contract | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	353		353		1,131
Derivative liabilities	1,318		1,318		0
Recurring | Interest swap contract | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0		0
Derivative liabilities	$ 0		$ 0		$ 0