Schedule of Consideration Transferred and Fair Value Assigned to Assets Acquired And Liabilities Assumed (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Nov. 30, 2014	May 31, 2014
Estimated Fair Value of Assets Acquired and Liabilities Assumed:
Goodwill	$ 283,418	$ 251,093
MEF
Consideration Transferred:
Cash consideration	35,232
Total consideration	38,392
Estimated Fair Value of Assets Acquired and Liabilities Assumed:
Accounts receivable	3,329
Inventories	3,550
Intangible assets	13,600
Property, plant and equipment	166
Total identifiable assets	20,645
Accounts payable	(555)
Accrued liabilities	(92)
Deferred revenue	(4,808)
Net assets	15,190
Goodwill	23,202
Purchase price	38,392
Less: estimated excess working capital	3,160
Cash paid at closing	35,232
JRE
Consideration Transferred:
Cash consideration	1,571
Estimated Fair Value of Assets Acquired and Liabilities Assumed:
Cash and cash equivalents	253
Accounts receivable	509
Inventories	2,793
Prepaid expenses and other current assets	40
Property, plant and equipment	250
Total identifiable assets	3,845
Accounts payable	(514)
Accrued liabilities	(2,160)
Net assets	1,171
Goodwill	400
Net assets	1,571
Cash paid at closing	1,571
DHybrid Systems Llc
Consideration Transferred:
Cash consideration	11,939
Fair value of contingent consideration	3,979
Total consideration	15,918
Estimated Fair Value of Assets Acquired and Liabilities Assumed:
Cash and cash equivalents	795
Accounts receivable	1,459
Inventories	3,300
Prepaid expenses and other current assets	38
Intangible assets	3,788
Property, plant and equipment	396
Total identifiable assets	9,776
Accounts payable	(1,163)
Accrued liabilities	(160)
Long-term debt	(5,000)
Net assets	3,453
Goodwill	16,547
Net assets	20,000
Purchase price	15,918
Noncontrolling interest	(4,082)
Total consideration	15,918
Cash paid at closing	$ 11,939