Income Taxes - Additional Information (Detail)	6 Months Ended
Jun. 30, 2017 USD ($)
Income Tax Contingency [Line Items]
Deferred tax assets, valuation allowance	$ 0
Internal Revenue Service [Member] \| Earliest Tax Year [Member]
Income Tax Contingency [Line Items]
Open tax year	2011
Internal Revenue Service [Member] \| Latest Tax Year [Member]
Income Tax Contingency [Line Items]
Open tax year	2014

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Tax year that remains open to examination under enacted tax laws, in CCYY format.

+ 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 (e)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319

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