Derivative Financial Instruments - Summary of Outstanding Foreign Currency Forward Contracts (Details) - Foreign Currency Forward Contracts - Cash Flow Hedges - Non-designated	9 Months Ended	12 Months Ended
	Sep. 30, 2018 USD ($) ¥ / ¥ € / $ £ / $ $ / ¥ $ / ¥ $ / $	Dec. 31, 2017 USD ($) € / $ £ / $ $ / ¥ $ / ¥ $ / $ € / £
Derivative One
Derivative [Line Items]
Notional Amount	$ 2,200,000	$ 2,494,000
Effective Date	Sep. 30, 2018	Dec. 31, 2017
Maturity Date	Nov. 30, 2018	Jan. 31, 2018
Index	EUR/GPB	EUR/GBP
Weighted Average Foreign Exchange Rate	0.89136	1.2009
Derivative Two
Derivative [Line Items]
Notional Amount	$ 11,482,000	$ 10,514,000
Effective Date	Sep. 30, 2018	Dec. 31, 2017
Maturity Date	Nov. 30, 2018	Jan. 31, 2018
Index	EUR/USD	EUR/USD
Weighted Average Foreign Exchange Rate | € / $	1.1659	1.2009
Derivative Three
Derivative [Line Items]
Notional Amount	$ 28,104,000	$ 10,612,000
Effective Date	Sep. 30, 2018	Dec. 31, 2017
Maturity Date	Nov. 30, 2018	Jan. 31, 2018
Index	GBP/USD	GBP/USD
Weighted Average Foreign Exchange Rate | £ / $	1.3068	1.3541
Derivative Four
Derivative [Line Items]
Notional Amount	$ 39,811,000	$ 31,834,000
Effective Date	Sep. 30, 2018	Dec. 31, 2017
Maturity Date	Nov. 30, 2018	Jan. 31, 2018
Index	USD/CNY	USD/CNY
Weighted Average Foreign Exchange Rate | $ / ¥	6.8889	6.5343
Derivative Five
Derivative [Line Items]
Notional Amount	$ 907,000	$ 1,594,000
Effective Date	Sep. 30, 2018	Dec. 31, 2017
Maturity Date	Nov. 30, 2018	Jan. 31, 2018
Index	USD/JPY	USD/JPY
Weighted Average Foreign Exchange Rate | $ / ¥	113.16	112.35
Derivative Six
Derivative [Line Items]
Notional Amount	$ 47,435,000	$ 30,594,000
Effective Date	Sep. 30, 2018	Dec. 31, 2017
Maturity Date	Nov. 30, 2018	Jan. 31, 2018
Index	USD/TWD	USD/TWD
Weighted Average Foreign Exchange Rate | $ / $	30.392	29.406