Summary of Significant Accounting Policies - Intangible Assets - Components of finite-lived intangible assets acquired (Details) (USD $)	12 Months Ended
	Apr. 30, 2014	Apr. 30, 2013
Components of finite-lived intangible assets acquired
Total gross carrying amount	$ 1,559,000	$ 1,559,000
Accumulated amortization	1,559,000	1,426,000
Net carrying amount	0	133,000
Customer Relationships
Components of finite-lived intangible assets acquired
Total gross carrying amount	758,000	758,000
Accumulated amortization	758,000	758,000
Net carrying amount	0	0
Weighted Average Life	2 years	2 years
Trade Names
Components of finite-lived intangible assets acquired
Total gross carrying amount	733,000	733,000
Accumulated amortization	733,000	600,000
Net carrying amount	0	133,000
Weighted Average Life	5 years	5 years
Noncompete Agreement
Components of finite-lived intangible assets acquired
Total gross carrying amount	68,000	68,000
Accumulated amortization	68,000	68,000
Net carrying amount	$ 0	$ 0
Weighted Average Life	4 years	4 years