Stock Incentive Plans - Data Concerning RSUs Granted (Details)	9 Months Ended
Sep. 30, 2018 $ / shares shares
Employees \| RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants during period (in shares) \| shares	1,511,893
Weighted Average Grant Date Fair Value Per Share (in dollars per share) \| $ / shares	$ 14.81
Director \| Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants during period (in shares) \| shares	51,226
Weighted Average Grant Date Fair Value Per Share (in dollars per share) \| $ / shares	$ 15.03

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).

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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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued 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).

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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.

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