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Stock-Based Compensation - Schedule of Stock Options Activity (Details) - USD ($) $ / shares in Units, $ in Millions | 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] |  |  |
Stock option awards granted | 0 | 0 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period | 0 |  |
Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price | $ 0.00 |  |
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price | $ 0.00 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] |  |  |
Outstanding options, beginning of year, number of shares | 642,255 |  |
Exercised, number of shares | (199,667) |  |
Forfeited, number of shares | (14,412) |  |
Outstanding options, end of year, number of shares | 428,176 | 642,255 |
Outstanding options exercisable, end of year, number of shares | 428,176 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward] |  |  |
Outstanding options, beginning of year, weighted average exercise price (in dollars per share) | $ 16.13 |  |
Exercised, weighted average exercise price (in dollars per share) | 17.12 |  |
Forfeited, weighted average exercise price (in dollars per share) | 20.87 |  |
Outstanding options, end of year, weighted average exercise price (in dollars per share) | 15.61 | $ 16.13 |
Outstanding options exercisable, end of year, weighted average exercise price (in dollars per share) | $ 15.61 |  |
Outstanding options, end of year weighted average remaining contractual term (in years) | 1 year 6 months 21 days |  |
Outstanding options exercisable, end of year, weighted average remaining contractual term (in years) | 1 year 6 months 21 days |  |
Stock Option |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Total intrinsic value of options exercised | $ 4.9 | $ 6.3 | $ 5.6
Proceeds from Stock Options Exercised | 1.8 | 2.4 | 4.7
Common Stock Redeemed For Payment of Stock Option Exercises, Aggregate Value | $ 1.6 | $ 2.8 | $ 3.1

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- Definition Amount of cash inflow 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 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585 + Details
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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=109197908&loc=d3e5070-113901 + Details
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