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Share-Based Transactions - Summary of Intrinsic Value, Tax Benefit Realized and Value of Shares Withheld Related to Option Exercise Activity (Details) - Employee Stock Option [Member] - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Intrinsic value of options exercised | $ 1,953 | $ 1,453 | $ 2,755
Tax benefit realized from the options exercised |  | 509 | 964
Value of issued shares withheld to satisfy option exercise price | $ 1,562 | $ 1,673 | $ 5,509

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- Definition Represents the value of shares that were withheld and not issued to settle the strike price of options exercised during the period. + References No definition available. + Details
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- Definition Amount of tax benefit from exercise of stock options granted under share-based compensation 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 2A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109197908&loc=SL79508275-113901 + Details
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- Definition 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 No definition available. + Details
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- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. + 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 (d)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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