Income Taxes - Balances of Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 51,079us-gaap_UnrecognizedTaxBenefits	$ 48,838us-gaap_UnrecognizedTaxBenefits	$ 51,244us-gaap_UnrecognizedTaxBenefits	$ 47,379us-gaap_UnrecognizedTaxBenefits
Portion that, if recognized, would reduce tax expense and effective tax rate	43,363	40,562	43,910
Accrued interest on unrecognized tax benefits	6,360	5,837	6,088
Accrued penalties on unrecognized tax benefits	697	99	127
Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months lower bound	0	0	0
Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months upper bound	10,331	6,722	11,479
Portion that, if recognized, would reduce tax expense and effective tax rate lower bound	0	0	0
Portion that, if recognized, would reduce tax expense and effective tax rate upper bound	$ 8,593	$ 4,984	$ 9,645

Unrecognized tax benefit portion that if recognized would reduce tax expense and effective tax rate lower bound.

No definition available.

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- Definition

Unrecognized tax benefit portion that if recognized would reduce tax expense and effective tax rate upper bound.

+ References

No definition available.

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- Definition

Amount of (increase) decrease reasonably possible in the estimated lower bound of the unrecognized tax benefit for a tax position taken or expected to be taken.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

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- Definition

Amount of (increase) decrease reasonably possible in the estimated upper bound of the unrecognized tax benefit for a tax position taken or expected to be taken.

+ References

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- Definition

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

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (a)

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

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- Definition

Amount of statutory penalties accrued for a tax position claimed or expected to be claimed by the entity, in its tax return.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

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- Definition

Amount of interest expense accrued for an underpayment of income taxes.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

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- Definition

The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

+ 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 (b)

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

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