Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Nov. 30, 2015	Nov. 30, 2014
OPERATING ACTIVITIES:
Net loss	$ (19,013)	$ (14,557)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	34,217	36,131
Noncash interest expense	5,429	5,420
Loss on disposition and retirement of fixed assets	443	75
Provision for doubtful accounts	360	20
Share-based compensation expense	2,780	1,467
Deferred income taxes	(7,208)	(10,096)
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable, trade	1,021	(3,770)
Income taxes	(309)	(25)
Inventories	(6,170)	(2,436)
Other assets	1,166	843
Accounts payable	(187)	2,726
Deferred revenue	156	(166)
Accrued expenses and other liabilities	(4,644)	(619)
Cash provided by operating activities	8,041	15,013
INVESTING ACTIVITIES:
Purchases of property and equipment	(3,889)	(6,903)
Other investments	(3,100)	(5,300)
Acquisitions of businesses, net of cash acquired	(750)	(6,396)
Cash used in investing activities	(7,739)	(18,599)
FINANCING ACTIVITIES:
Repayments of long-term debt	(3,323)	(3,328)
Proceeds from Revolving Facility	28,000	29,500
Repayments of Revolving Facility	(28,000)	(29,500)
Cash used in financing activities	(3,323)	(3,328)
EFFECT OF EXCHANGE RATES ON CASH AND CASH EQUIVALENTS	(275)	(1,602)
DECREASE IN CASH AND CASH EQUIVALENTS	(3,296)	(8,516)
Cash and cash equivalents at beginning of period	18,363	23,621
Cash and cash equivalents at end of period	15,067	15,105
SUPPLEMENTAL INFORMATION:
Income taxes paid, net of refunds	2,053	2,325
Interest paid	39,514	39,702
NON-CASH INVESTING AND FINANCING ACTIVITIES:
Movement from inventory to property and equipment of instruments placed on rental agreements	$ 2,691	$ 3,069