FAIR VALUE MEASUREMENTS (Details) (USD $)	3 Months Ended		9 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Apr. 30, 2014	Apr. 30, 2013
Liabilities
Impairments related to goodwill and property and equipment	$ 500,000	$ 900,000	$ 488,000	$ 851,000
Store-level property and equipment
Liabilities
Impairments related to goodwill and property and equipment			500,000	900,000
Cost | Store-level property and equipment
Liabilities
Store-level property and equipment			700,000	1,000,000
Fair Value
Assets
Investments			21,312,000	27,938,000
Fair Value | U.S. Treasury securities
Assets
Investments			9,941,000	19,572,000
Fair Value | U.S. government agency securities
Assets
Investments			2,044,000	2,800,000
Fair Value | Corporate bonds and notes
Assets
Investments			6,841,000	866,000
Fair Value | Corporate equity securities
Assets
Investments			2,486,000	4,700,000
Level 3 | Minimum
Liabilities
Weighted average cost of capital (as a percent)			14.00%
Level 3 | Maximum
Liabilities
Weighted average cost of capital (as a percent)			15.50%
Level 3 | Store-level property and equipment | Minimum
Liabilities
Weighted average cost of capital (as a percent)			14.00%
Level 3 | Store-level property and equipment | Maximum
Liabilities
Weighted average cost of capital (as a percent)			15.50%
Recurring basis | Level 1
Assets
Total assets			12,427,000	24,272,000
Recurring basis | Level 1 | U.S. Treasury securities
Assets
Investments			9,941,000	19,572,000
Recurring basis | Level 1 | Corporate equity securities
Assets
Investments			2,486,000	4,700,000
Recurring basis | Level 2
Assets
Total assets			8,885,000	3,666,000
Recurring basis | Level 2 | Interest rate swaps
Liabilities
Derivative			2,689,000
Recurring basis | Level 2 | U.S. government agency securities
Assets
Investments			2,044,000	2,800,000
Recurring basis | Level 2 | Corporate bonds and notes
Assets
Investments			6,841,000	866,000
Nonrecurring basis | Level 3 | Store-level property and equipment
Liabilities
Store-level property and equipment			$ 200,000	$ 100,000