Components of Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components Of Income Tax Expense Benefit [Line Items]
U.S. Federal	$ 86,719	$ 85,585	$ 74,561
State	9,801	9,431	10,325
Foreign	9,416	9,661	6,953
Income tax expense	105,936	104,677	91,839
Current	103,216	99,990	91,550
Deferred	2,720	4,687	289
Income tax expense	$ 105,936	$ 104,677	$ 91,839

Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32639-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Current Tax Expense (or Benefit)
-URI http://asc.fasb.org/extlink&oid=6509736

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Subparagraph (SX 210.4-08(h))
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Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Deferred Tax Expense (or Benefit)
-URI http://asc.fasb.org/extlink&oid=63044130

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Amount of current and deferred federal income tax expense (benefit) attributable to income (loss) from continuing operations.

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-Publisher FASB
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Amount of current and deferred foreign income tax expense (benefit) attributable to income (loss) from continuing operations.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of state and local current and deferred income tax expense (benefit) attributable to continuing operations.

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Components Of Income Tax Expense Benefit [Line Items]

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