Summary of Preliminary Fair Values and Purchase Price Allocation at Acquisition Date of Assets Acquired and Liabilities Assumed (Detail) (USD $) In Thousands, unless otherwise specified			1 Months Ended
	Mar. 31, 2014	Sep. 30, 2013	Mar. 31, 2014 Griffith Energy Services, Inc.		Mar. 31, 2014 Griffith Energy Services, Inc. Customer lists, trade names and other intangibles
Business Acquisition [Line Items]
Trade accounts receivable			$ 46,557	[1]
Inventories			5,143
Other current assets			5,459
Property and equipment			17,555
Intangible assets					49,157
Other long term assets			1,778
Current liabilities			(30,089)
Total net identifiable assets acquired			95,560
Total consideration			98,698
Less: Total net identifiable assets acquired			95,560
Goodwill	$ 204,268	$ 201,130	$ 3,138

[1] The gross contractual receivable amount is $48.2 million, and the best estimate at the acquisition date of the contractual cash flows not expected to be collected is $1.7 million.