Derivatives - Forward Notional Contracts (Details) - Mar. 31, 2018 - Foreign currency forward contracts € in Thousands, ₩ in Thousands, ¥ in Thousands, ¥ in Thousands, £ in Thousands, kr in Thousands, kr in Thousands, SFr in Thousands, R$ in Thousands, $ in Thousands, $ in Thousands, $ in Thousands, $ in Thousands, $ in Thousands	HKD ($)	DKK (kr)	MXN ($)	CNY (¥)	KRW (₩)	GBP (£)	CAD ($)	JPY (¥)	SGD ($)	SEK (kr)	CHF (SFr)	BRL (R$)	EUR (€)	AUD ($)
Designated as hedging instrument | Derivatives designated as cash flow hedges
Derivative [Line Items]
Notional amount of derivative		kr 11,140	$ 69,475	¥ 15,000		£ 2,845	$ 1,710			kr 12,620	SFr 1,048		€ 6,495
Not designated as hedging instrument
Derivative [Line Items]
Notional amount of derivative	$ 11,000	kr 2,230	$ 17,860	¥ 24,500	₩ 1,800,000	£ 1,497	$ 2,738	¥ 255,000	$ 6,200	kr 7,987	SFr 255	R$ 8,500	€ 23,966	$ 6,993