Acquisitions (Schedule Of Business Acquisitions, Consideration Paid And Net Assets Acquired) (Detail) (USD $)				12 Months Ended			0 Months Ended			0 Months Ended				0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Earn-out Arrangements [Member]	Dec. 31, 2012 Earn-out Arrangements [Member]	Dec. 31, 2011 Earn-out Arrangements [Member]	May 01, 2013 Big Country [Member]	May 02, 2013 Big Country [Member]	May 02, 2013 Big Country [Member] Pre-Qualifications [Member]	May 01, 2013 Big Country [Member] Earn-out Arrangements [Member]	May 02, 2011 EC Source [Member]	May 03, 2011 EC Source [Member]	May 03, 2011 EC Source [Member] Pre-Qualifications [Member]	May 02, 2011 EC Source [Member] Earn-out Arrangements [Member]	May 02, 2011 EC Source [Member] Common Stock [Member]
Purchase price consideration:
Shares transferred															$ 94,200,000
Cash							103,500,000				300,000
Fair value of contingent consideration (earn-out liability)				29,971,000	66,700,000	48,111,000				22,800,000				25,000,000
Total consideration transferred							126,300,000				119,500,000
Fair value of equity investment											39,600,000
Fair value of total consideration											159,100,000
Identifiable assets acquired and liabilities assumed:
Current assets								69,000,000
Property and equipment								43,500,000
Pre-qualifications									29,600,000				31,300,000
Finite-lived intangible assets								10,700,000				12,500,000
Current liabilities								(23,000,000)
Long-term debt	(9,800,000)	(20,600,000)						(24,400,000)
Deferred income taxes								(14,300,000)
Total identifiable net assets								91,100,000				38,400,000
Goodwill	899,364,000	826,629,000	714,800,000					35,200,000				120,700,000
Total net assets acquired, including goodwill								$ 126,300,000				$ 159,100,000