Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Feb. 28, 2014
Income Tax Disclosure [Abstract]
Deferred tax assets	$ 45
Federal net operating loss and tax credit carryforwards	31
State net operating loss carryforwards	8
Differences between financial and tax reporting	$ 6
Federal net operating loss and tax credit carryforwards life expectancy	20 years
State net operating loss carryforwards life expectancy, minimum	5 years
State net operating loss carryforwards life expectancy, maximum	20 years