Stock Plans - Schedule of Stock Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement [Abstract]
Restricted stock units	$ 6,258	$ 6,914	$ 6,221
Stock options	113	487	217
Performance stock units	549	6,359	5,801
Total stock-compensation expense before income taxes	6,920	13,760	12,239
Income tax benefit	1,668	3,357	2,974
Total stock-compensation expense, net of income tax benefit	$ 5,252	$ 10,403	$ 9,265

Performance stock expense.

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- Definition

Amount, after tax, of expense for award under share-based payment arrangement.

+ References

No definition available.

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- References

No definition available.

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- Definition

Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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- Definition

Amount of noncash expense for award of restricted stock or unit under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

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- Definition

Amount of noncash expense for share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

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- Definition

Amount of noncash expense for option under share-based payment arrangement.

+ References

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