Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	May 31, 2016 USD ($) plaintiff	May 31, 2015 USD ($)	May 31, 2014 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Advertising expenses	$ 1,133,000	$ 982,000	$ 982,000
Shipping and handling cost	3,634,000	3,953,000	3,977,000
Depreciation of rental and lease equipment	55,931,000	56,445,000	57,034,000
Depreciation of equipment, straight line	407,807,000	440,495,000
Depreciation of equipment, accelerated	27,106,000	32,292,000
Rental and lease equipment at net book value	$ 199,525,000	231,671,000
Tax impact realization likelihood percentage	50.00%
Rental and lease equipment impairment	$ 443,000	0	$ 0
Demonstration equipment	$ 4,851,000	$ 81,000
Trade accounts receivable terms	30 days
Assets, liabilities, revenues and expenses of foreign subsidiaries	less than 10.0% of our respective consolidated amounts
Restatement of previously recognized revenue	$ 1,344,000
Agilent
Summary Of Significant Accounting Policies [Line Items]
Percentage of new equipment purchases	56.00%	70.70%	65.60%
Building
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	31 years 6 months
T&M equipment
Summary Of Significant Accounting Policies [Line Items]
Rental and lease equipment at net book value	$ 194,618,000	$ 225,222,000
Rental and lease equipment impairment	443,000
DP equipment
Summary Of Significant Accounting Policies [Line Items]
Rental and lease equipment at net book value	$ 4,908,000	$ 6,449,000
Minimum
Summary Of Significant Accounting Policies [Line Items]
Operating lease agreements Period	1 year
Finance lease agreements Period	1 year
Property plant and equipment, useful life	2 years
Minimum | Furniture and other equipment
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Minimum | Leasehold improvements
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Minimum | Equipment
Summary Of Significant Accounting Policies [Line Items]
Property plant and equipment, useful life	2 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Operating lease agreements Period	3 years
Finance lease agreements Period	3 years
Property plant and equipment, useful life	4 years
Period for demonstration equipment included in other assets	2 years
Maximum | Leasehold improvements
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Maximum | Equipment
Summary Of Significant Accounting Policies [Line Items]
Property plant and equipment, useful life	10 years
Other Income
Summary Of Significant Accounting Policies [Line Items]
Proceeds from legal settlements	$ 1,390,000
Parent Company [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of plaintiffs | plaintiff	1
Supplier Concentration Risk | New equipment purchases | Anritsu
Summary Of Significant Accounting Policies [Line Items]
Concentration risk (percentage)	12.30%