Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance of unrecognized tax benefits at beginning of year	$ 21,553us-gaap_UnrecognizedTaxBenefits	$ 41,153us-gaap_UnrecognizedTaxBenefits		$ 67,615us-gaap_UnrecognizedTaxBenefits
Gross amount of increases in unrecognized tax benefits as a result of positions taken during a prior year	1,795	7,364	22,031
Gross amount of decreases in unrecognized tax benefits as a result of positions taken during a prior year	(823)	(993)	(1,853)
Gross amount of increases in unrecognized tax benefits as a result of positions taken during the current year	5,378	4,951	3,854
The amounts of decreases in unrecognized benefits relating to settlements with taxing authorities	0	(26,712)	(48,355)
Reduction in unrecognized tax benefits due to the lapse of applicable statute of limitation	(4,848)	(4,210)	(2,139)
Balance of unrecognized tax benefits at end of year	$ 23,055us-gaap_UnrecognizedTaxBenefits	$ 21,553us-gaap_UnrecognizedTaxBenefits	$ 41,153us-gaap_UnrecognizedTaxBenefits	$ 67,615us-gaap_UnrecognizedTaxBenefits

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Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Unrecognized Tax Benefit

-URI http://asc.fasb.org/extlink&oid=6527854

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

-Section 50

-Paragraph 15A

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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