Derivative Financial Instruments (Details 4) - USD ($) $ in Millions	Jan. 31, 2016	Apr. 30, 2015
Commodity contracts [Member]
Outstanding derivative contracts
Gross contract notional amount	$ 712.0	$ 640.6
Foreign currency exchange contracts [Member]
Outstanding derivative contracts
Gross contract notional amount	$ 177.8	$ 136.4

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant