Income Taxes - Summary of Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Balance at beginning of period	$ 874	$ 777
Additions based on tax positions related to the current year	0	109
Reductions due to statute of limitations expiring	(301)	(174)
Reductions based on tax positions related to prior years	(78)	0
Balance at end of period	$ 495	$ 712

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Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

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- Definition

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

+ References

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

+ References

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-Name Accounting Standards Codification
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