Summary of Final Fair Values and Purchase Price Allocation at Acquisition Date of Assets Acquired and Liabilities Assumed (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2014 Griffith Energy Services, Inc.	Mar. 04, 2014 Griffith Energy Services, Inc.		Mar. 04, 2014 Griffith Energy Services, Inc. Customer lists, trade names and other intangibles
Business Acquisition [Line Items]
Trade accounts receivable					$ 49,010	[1]
Inventories					5,143
Other current assets					2,984
Property and equipment	17,600	200	8,000		17,263
Intangible assets							44,400
Other long term assets					1,778
Current liabilities					(31,096)
Total net identifiable assets acquired					89,482
Total consideration					97,650
Less: Total net identifiable assets acquired					89,482
Goodwill	$ 209,331	$ 201,130	$ 201,103	$ 8,200	$ 8,168

[1] The gross contractual receivable amount is $50.7 million, and the best estimate at the Acquisition Date of the contractual cash flows not expected to be collected is $1.7 million.