Acquisitions - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended			12 Months Ended
	Aug. 24, 2011	Feb. 29, 2012	Nov. 30, 2011	Aug. 31, 2011	May 31, 2012	May 31, 2011	Aug. 31, 2012
Business Acquisition [Line Items]
Amount deposited into an escrow account for any post-closing adjustments	$ 10,673						$ 500
Acquired gross accounts receivable	542						972
Acquired gross accounts receivable not expected to be collected							430
Acquired gross accounts receivable resulting in fair value							542
Bargain purchase gain related to EMT	3,194			3,194	3,435	202
Acquisition-related transaction cost					55
Revenues from acquired assets					5,232
Income before income taxes from acquired assets					2,862
Increased bargain purchase gain		396	396
Deferred taxes, net		241	241
Estimated fair value of customer relationships acquired		140	140
Post closing adjustments, disbursed from the escrow funds		273	273
Determination of assets acquired and other components		17	17
Determination of fair value of assets and liabilities acquired	13,867
Telogy LLC
Business Acquisition [Line Items]
Increased bargain purchase gain						342
Deferred taxes, net						202
Determination of assets acquired and other components						260
Determination of fair value of assets and liabilities acquired						$ 82