Derivative and Hedging Activities - Gain Loss in Statement of Operations (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain, net arising during the period		$ 0	$ 0	$ 202
Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion	[1]	0	0	(44)
Cost of revenue [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion	[1]	0	0	(6)
Operating expense [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion	[1]	0	0	(38)
Other Nonoperating Income (Expense) [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Losses) Recognized in Income on Derivatives (Amount Excluded from Effectiveness Testing	[1]	0	0	(63)
Other Nonoperating Income (Expense) [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recorded in other expense, net		(2,325)	155	343
Other Comprehensive Income (Loss) [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain, net arising during the period	[1]	$ 0	$ 0	$ 202

[1] The Company did not enter into any new cash flow hedge contracts since December 31, 2016.