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Stock Compensation Plans - Summary of Information about Stock Options Outstanding (Detail) - $ / shares | 12 Months Ended |
--- | --- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Number of Options Outstanding | 10,435,990 |  |
Number of Options, Exercisable | 8,449,389 | 7,936,659 | 6,946,677
July 27, 2011 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Exercise Price | $ 12.50 |  |
Number of Options Outstanding | 907,101 |  |
Weighted-Average Remaining Contractual Life | 2 years |  |
Number of Options, Exercisable | 907,101 |  |
December 20, 2012 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Exercise Price | $ 14.50 |  |
Number of Options Outstanding | 1,009,819 |  |
Weighted-Average Remaining Contractual Life | 3 years |  |
Number of Options, Exercisable | 1,009,819 |  |
December 19, 2013 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Exercise Price | $ 15.90 |  |
Number of Options Outstanding | 1,991,804 |  |
Weighted-Average Remaining Contractual Life | 4 years |  |
Number of Options, Exercisable | 1,991,804 |  |
December 18, 2014 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Exercise Price | $ 15.80 |  |
Number of Options Outstanding | 1,270,581 |  |
Weighted-Average Remaining Contractual Life | 5 years |  |
Number of Options, Exercisable | 1,270,581 |  |
December 17, 2015 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Exercise Price | $ 13.64 |  |
Number of Options Outstanding | 1,191,845 |  |
Weighted-Average Remaining Contractual Life | 1 year |  |
Number of Options, Exercisable | 1,191,845 |  |
December 15, 2016 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Exercise Price | $ 16.48 |  |
Number of Options Outstanding | 1,202,808 |  |
Weighted-Average Remaining Contractual Life | 2 years |  |
Number of Options, Exercisable | 1,202,808 |  |
December 21, 2017 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Exercise Price | $ 17.60 |  |
Number of Options Outstanding | 799,832 |  |
Weighted-Average Remaining Contractual Life | 3 years |  |
Number of Options, Exercisable | 533,168 |  |
December 20, 2018 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Exercise Price | $ 13.69 |  |
Number of Options Outstanding | 1,016,800 |  |
Weighted-Average Remaining Contractual Life | 4 years |  |
Number of Options, Exercisable | 338,930 |  |
March 4, 2019 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Exercise Price | $ 13.51 |  |
Number of Options Outstanding | 10,000 |  |
Weighted-Average Remaining Contractual Life | 4 years 2 months 12 days |  |
Number of Options, Exercisable | 3,333 |  |
December 19, 2019 [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Exercise Price | $ 14.98 |  |
Number of Options Outstanding | 1,035,400 |  |
Weighted-Average Remaining Contractual Life |  | 5 years |

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- Definition The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan. + 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 (c)(1)(iii) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices. + 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 (c)(1)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + 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 (e)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices. + 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 (c)(1)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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