Discontinued Operations - Narrative (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended		3 Months Ended
	Feb. 28, 2015 buyer transaction	Feb. 28, 2014	Feb. 28, 2015
Discontinued Operations and Disposal Groups [Abstract]
Number of transactions involved in sale of business	3
Number of buyers involved in sale of business	3
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds received, net of cash contributed	$ 154,891	$ 0
Discontinued Operations | Storage Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds received, net of cash contributed	$ 154,900		$ 900