Final Estimated Fair Value of Assets Acquired and Liabilities Assumed at Date of Acquisition (Detail) (Maverick Companies, USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Maverick Companies
Business Acquisition [Line Items]
Current Assets	$ 17,112
Property and Equipment	92,856
Other Intangible Assets	29,400	[1]
Goodwill	60,381	[2]
Other Non-Current Assets	464
Total Assets Acquired	200,213
Current Liabilities	11,824
Deferred Income Taxes
Total Liabilities Assumed	11,824
Net Assets Acquired	$ 188,389

[1] Other intangible assets consists of customer relationship of $25.3 million, amortizable over 15 years, non-compete agreements of $3.6 million, amortizable over five years, intellectual property of $380,000, amortizable over 15 years, and trade name of $170,000 with an indefinite life.

[2] Goodwill is primarily attributable to operational and cost synergies expected to be realized from the acquisition by integrating Maverick's equipment and assembled workforce. All of the goodwill is expected to be deductible for tax purposes.