Goodwill and Other Intangible Assets - Carrying Amount and Accumulated Amortization of Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2013	Feb. 28, 2013
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life (in years)	5 years 9 months 18 days	6 years 2 months 12 days
Gross Carrying Amount	$ 40,394	$ 40,394
Accumulated Amortization	21,211	19,621
Amortized intangible assets, net	19,183	20,773
Trade names [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life (in years)
Gross Carrying Amount	1,234	1,234
Accumulated Amortization	1,234	1,234
Amortized intangible assets, net
Customer lists [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life (in years)	5 years 10 months 24 days	6 years 4 months 24 days
Gross Carrying Amount	37,887	37,887
Accumulated Amortization	19,279	17,753
Amortized intangible assets, net	18,608	20,134
Noncompete [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life (in years)
Gross Carrying Amount	500	500
Accumulated Amortization	500	500
Amortized intangible assets, net
Patent [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life (in years)	4 years 6 months	5 years
Gross Carrying Amount	773	773
Accumulated Amortization	198	134
Amortized intangible assets, net	$ 575	$ 639