Stock-Based Compensation Plans - Summary of Restricted Stock Units, Performance Stock Units, and Restricted Stock (Details) shares in Thousands	12 Months Ended
Dec. 31, 2018 shares
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, granted (in shares)	56
Award vesting period (in years)	3 years
Tranche One \| Restricted Stock Units (RSU)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, granted (in shares)	10
Award vesting period (in years)	1 year
Tranche One \| Performance Share Units (PSU)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, granted (in shares)	49
Performance and service period under adopted ELTI Plan	3 years
Tranche Two \| Restricted Stock Units (RSU)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, granted (in shares)	48
Award vesting period (in years)	3 years
Tranche Two \| Performance Share Units (PSU)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, granted (in shares)	207
Award vesting period (in years)	4 years
Performance and service period under adopted ELTI Plan	3 years
Tranche Three \| Restricted Stock Units (RSU)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, granted (in shares)	79
Award vesting period (in years)	4 years

Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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 (a)(1)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target 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)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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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.

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No definition available.

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