Note 16 - Fair Value (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2016	May 31, 2015	May 31, 2014	May 31, 2013
Cas and Cash Equivalents [Member] | Geographic Concentration Risk [Member] | UNITED STATES
Concentration Risk, Percentage	38.00%	37.00%
Notes Payable, Other Payables [Member]
Long-term Debt, Fair Value	$ 364,300	$ 424,300
Term Loan Facility [Member]
Long-term Debt, Fair Value	614,500	653,300
Contingent Consideration [Member]
Business Combination, Contingent Consideration, Liability	40,400	18,600
Accrued Expenses and Other Current Liabilities [Member]
Business Combination, Contingent Consideration, Liability		100
Other Noncurrent Liabilities [Member]
Other Liabilities, Noncurrent		18,500
Cash and Cash Equivalents, at Carrying Value	10,263	18,363	$ 23,621	$ 29,388
Business Combination, Contingent Consideration, Liability	40,356	18,596	$ 11,300
Other Liabilities, Noncurrent	$ 57,420	$ 29,212