Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Level 1
Assets:
Total Assets	$ 0	$ 0
Liabilities:
Total Liabilities	0	0
Level 1 | Foreign currency forward exchange contracts
Assets:
Foreign currency contract, asset fair value	0	0
Liabilities:
Foreign currency contract, liability fair value	0	0
Level 1 | Foreign currency option contracts
Assets:
Foreign currency contract, asset fair value	0	0
Level 2
Assets:
Total Assets	7,804	7,746
Liabilities:
Total Liabilities	30,226	35,386
Level 2 | Foreign currency forward exchange contracts
Assets:
Foreign currency contract, asset fair value	7,691	7,660
Liabilities:
Foreign currency contract, liability fair value	30,226	35,386
Level 2 | Foreign currency option contracts
Assets:
Foreign currency contract, asset fair value	113	86
Level 3
Assets:
Total Assets	0	0
Liabilities:
Total Liabilities	0	0
Level 3 | Foreign currency forward exchange contracts
Assets:
Foreign currency contract, asset fair value	0	0
Liabilities:
Foreign currency contract, liability fair value	0	0
Level 3 | Foreign currency option contracts
Assets:
Foreign currency contract, asset fair value	0	0
Fair Value
Assets:
Total Assets	7,804	7,746
Liabilities:
Total Liabilities	30,226	35,386
Fair Value | Foreign currency forward exchange contracts
Assets:
Foreign currency contract, asset fair value	7,691	7,660
Liabilities:
Foreign currency contract, liability fair value	30,226	35,386
Fair Value | Foreign currency option contracts
Assets:
Foreign currency contract, asset fair value	$ 113	$ 86