Note 17. Income Taxes (Detail) - Unrecognized Tax Benefits (USD $) In Thousands, unless otherwise specified	12 Months Ended
May 31, 2012	May 31, 2011
Balance, beginning of period	$ 9,766	$ 8,093
Change due to Acquisition	1,018
Gross increases in unrecognized tax benefits as a result of tax positions taken during a prior period	0	0
Gross decreases in unrecognized tax benefits as a result of tax positions taken during a prior period	0	0
Gross increases in unrecognized tax benefits as a result of tax positions taken during current period	5,314	2,107
Gross decreases in unrecognized tax benefits as a result of tax positions taken during current period	0	0
Decrease in unrecognized tax benefits relating to settlements with taxing authorities	0	0
Reductions to unrecognized tax benefits as a result of the applicable statute of limitations	(1,267)	(434)
Balance, end of period	$ 14,831	$ 9,766

The gross amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns as of the balance sheet date.

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