Derivatives and Financial Instruments Derivatives and Financial Instruments (Details) - USD ($) number in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jul. 31, 2018	Oct. 31, 2018	Feb. 28, 2018	Mar. 01, 2016	Sep. 01, 2015	Feb. 24, 2014
Derivative [Line Items]
Derivatives, Interest Rate Swap, Maturity			5 years
Interest expense	$ 3,355	$ 2,340
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount, Second Amount Per Base							$ 25,000
Derivative, Notional Amount, Final Amount Per Base						$ 25,000
Other Liabilities [Member] | Cash Flow Hedging [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Liability	(350)			$ 135
Euro Member Countries, Euro | Cross Currency Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount					$ 53,000
London Interbank Offered Rate (LIBOR) [Member] | Cross Currency Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount					$ 64,930
Interest Expense [Member]
Derivative [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax	(368)	$ 280
Lender Group Two [Member] | Revolving Credit Facility [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount								$ 75,000
Derivative, Fixed Interest Rate								0.00%
Derivative, Notional Amount, Amount Per Base								$ 25,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Cross Currency Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	3,857			4,432
Derivative Liability				4,432
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	$ (350)
Derivative Liability				$ 135