Estimated Fair Value of Assets Acquired and Liabilities Assumed (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Aug. 31, 2012
Assets acquired:
Current assets		$ 211,052	[1]
Property and equipment		90,729	[1]
Goodwill		25,042	[1]
Intangible assets		21,543	[1]
Other noncurrent assets		11,664	[1]
Total assets		360,030	[1]
Assets acquired:
Current assets	211,052
Property and equipment	90,729
Goodwill	25,042	25,000
Intangible assets	21,543
Other noncurrent assets	11,664
Total assets	360,030
Liabilities assumed:
Current liabilities		190,485	[1]
Noncurrent liabilities		12,237	[1]
Total liabilities		202,722	[1]
Fair value of net assets acquired, net of cash	157,308	157,308	[1]
Liabilities assumed:
Current liabilities	190,485
Noncurrent liabilities	12,237
Total liabilities	202,722
Fair value of net assets acquired, net of cash	157,308	157,308	[1]
Assets acquired:
Current assets
Property and equipment
Goodwill
Intangible assets
Other noncurrent assets
Total assets
Liabilities assumed:
Current liabilities
Noncurrent liabilities
Total liabilities
Fair value of net assets acquired, net of cash

[1] As previously reported in our 2012 Form 10-K.