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Capital Stock - Additional Information (Detail) - USD ($) |  |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Nov. 06, 2018 | Feb. 24, 2017 | Oct. 31, 2015 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Capital Stock [Line Items] |  |  |  |  |  |
Additional common stock at an aggregate purchase price |  | $ 150,000,000 | $ 300,000,000 |  |  |
Common stock repurchased |  |  |  | $ 27,288,000 | $ 30,369,000 | $ 222,986,000
Share Repurchase Program |  |  |  |  |  |
Capital Stock [Line Items] |  |  |  |  |  |
Additional common stock at an aggregate purchase price | $ 250,000,000 |  |  | $ 22,000,000.0 | $ 20,000,000.0 |
Common stock repurchased (shares) |  |  |  | 338,521 | 443,877 | 4,523,934
Common stock repurchased |  |  |  |  |  | $ 214,700,000
Stock repurchase program, remaining authorized repurchase amount |  |  |  | $ 143,400,000 |  |
Stock repurchase program, term | 3 years |  |  |  |  |

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- Definition Capital Stock [Line Items] + References No definition available. + Details
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- Definition Stock repurchase program additional authorized amount for share repurchase program. + References No definition available. + Details
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- Definition Period which shares may be purchased under a stock repurchase plan authorized by an entity's Board of Directors, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Amount remaining of a stock repurchase plan authorized. + References No definition available. + Details
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- Definition Number of shares that have been repurchased during the period and are being held in treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 + Details
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