Financial Instruments Foreign currency forward contracts (Details) - Sep. 30, 2016 - Not Designated as Hedging Instrument - Forward Contracts	GBP (£)	AUD	EUR (€)	INR (₨)	USD ($)
AUD/EUR | Currency Purchased Forward
Derivative [Line Items]
Outstanding foreign currency forward contract | AUD		AUD 3,900,000
AUD/EUR | Currency Sold Forward
Derivative [Line Items]
Outstanding foreign currency forward contract			€ 2,658,849
USD/EUR | Currency Purchased Forward
Derivative [Line Items]
Outstanding foreign currency forward contract			5,340,454
USD/EUR | Currency Sold Forward
Derivative [Line Items]
Outstanding foreign currency forward contract | $					$ 6,000,000
EUR/GBP | Currency Purchased Forward
Derivative [Line Items]
Outstanding foreign currency forward contract			10,250,000
EUR/GBP | Currency Sold Forward
Derivative [Line Items]
Outstanding foreign currency forward contract | £	£ 8,887,160
INR/USD | Currency Purchased Forward
Derivative [Line Items]
Outstanding foreign currency forward contract | ₨				₨ 261,387,750
INR/USD | Currency Sold Forward
Derivative [Line Items]
Outstanding foreign currency forward contract | $					$ 3,900,000
INR/EUR | Currency Purchased Forward
Derivative [Line Items]
Outstanding foreign currency forward contract | ₨				₨ 323,893,630
INR/EUR | Currency Sold Forward
Derivative [Line Items]
Outstanding foreign currency forward contract			€ 4,300,000