Fair Values (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Values Convertible Debt Hedges, Gain (Loss)	$ 0	$ 1,470
Convertible Senior Notes at 5.00% February 2021 [Member] | Convertible Subordinated Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Values Convertible Debt Hedges, Gain (Loss)			$ 0	$ 1,197
Convertible Debt Bond Hedge | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible 2021 note hedge asset	0		0
Forward exchange contracts—net | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities), at fair value, net	0		0		$ 0
Forward exchange contracts—net | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities), at fair value, net	1,142		1,142		(67)
Forward exchange contracts—net | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities), at fair value, net	$ 0		$ 0		$ 0