Capital Lease Obligation (Details Textual) (USD $)	9 Months Ended
	Feb. 28, 2013	Feb. 28, 2013 Furniture and Fixtures [Member]	Feb. 28, 2013 Digital Systems [Member]	May 31, 2012 Digital Systems [Member]
Capital Leased Assets, Number of Units	642
Capital Leases, Balance Sheet, Assets by Major Class, Net		$ 45,510,000		$ 43,878,000
Finite-Lived Intangible Assets, Accumulated Amortization			6,302,000	2,933,000
Commitment Minimum Lease Payments	6,163,000
Payments Obligation Reduced Amount	$ 4,481,000
Expect Period Of Payments Obligation	12 months