Line of Credit - Interest Rate Swaps (Details) $ in Millions	Oct. 31, 2016 USD ($)	May 31, 2016 USD ($) instrument	Apr. 30, 2016 USD ($)	Oct. 31, 2015 USD ($)
Line of Credit Facility [Line Items]
Effective portion of cash flow hedges included in accumulated other comprehensive loss, before tax	$ 0.2			$ 0.2
Interest Rate Swap
Line of Credit Facility [Line Items]
Notional amount		$ 105.0	$ 155.0
Derivative, Number of Instruments Held | instrument		3
Derivative, fixed interest rate		1.05%