Revision of 2011 and 2012 Financial Statements - Effect of Revisions on Affected Line Items on Condensed Consolidated Statement of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Consolidated Statement of Cash Flows Data:
Net income	$ (27,024)	$ 138,970	$ 309,086
Provision for doubtful accounts	67,640	56,818	35,655
Deferred income taxes	(54,425)	(59,999)	(8,991)
Restricted cash	(455)	3,794	(942)
Accounts receivable	(87,225)	(87,138)	(17,004)
Other operating assets and liabilities	74,203	72,857	35,964
Net cash flows from operating activities	77,725	107,621	388,763
As Previously Reported [Member]
Condensed Consolidated Statement of Cash Flows Data:
Net income		140,465	307,752
Provision for doubtful accounts		78,307	61,308
Deferred income taxes		(58,640)	(8,991)
Restricted cash		1,527	(1,873)
Accounts receivable		(107,514)	(40,477)
Other operating assets and liabilities		68,890	35,118
Net cash flows from operating activities		105,354	387,832
Revisions [Member]
Condensed Consolidated Statement of Cash Flows Data:
Net income		(1,495)	1,334
Provision for doubtful accounts		(21,489)	(25,653)
Deferred income taxes		(1,359)	0
Restricted cash		2,267	931
Accounts receivable		20,376	23,473
Other operating assets and liabilities		3,967	846
Net cash flows from operating activities		2,267	931
As Revised [Member]
Condensed Consolidated Statement of Cash Flows Data:
Net income		138,970	309,086
Provision for doubtful accounts		56,818	35,655
Deferred income taxes		(59,999)	(8,991)
Restricted cash		3,794	(942)
Accounts receivable		(87,138)	(17,004)
Other operating assets and liabilities		72,857	35,964
Net cash flows from operating activities		$ 107,621	$ 388,763