Contingencies (Details)	12 Months Ended
	Apr. 30, 2015 USD ($) report lawsuit state	Apr. 30, 2014 USD ($)
Loss Contingency [Abstract]
Other accrued liabilities	$ 388,000	$ 300,000
Period covered by lawsuit	2 years
Number of consumer reports obtained | report	3,900
Loss Contingencies
Number of states in which entity operates | state	14
Annual stop loss limit	$ 1,000,000
Letters of credit outstanding	19,155,000	15,000,000
Investments In escrow for insurance	$ 223,000
Number of states that require partial self-insurance | state	1
Self-insurance reserves	$ 31,389,000	$ 28,429,000
Minimum
Loss Contingencies
Statutory damages per violation	100
Maximum
Loss Contingencies
Statutory damages per violation	$ 1,000
Motor Fuel Temperature Sales Practices (Hot Fuel)
Loss Contingencies
Number of lawsuits | lawsuit	4