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).

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 number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ 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)(2)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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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.

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- Definition

Net number of non-option equity instruments granted to participants.

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

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- Definition

Percentage of vesting of share-based compensation awards.

+ References

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-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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Stock-Based Plans and Stock-Based Compensation - Restricted Stock Unit Activity (Details) - RSUs - $ / shares	1 Months Ended							12 Months Ended
	Oct. 31, 2018	Jun. 30, 2018	May 31, 2018	Feb. 28, 2018	Nov. 30, 2017	Jun. 30, 2017	Feb. 28, 2017	Dec. 31, 2018	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units granted	2,602	12,806.1224489796		46,785	4,393	14,526	59,395		52,503
Units granted, weighted average grant date fair value (usd per share)	$ 17.23	$ 19.60		$ 18.25	$ 19.35	$ 17.45	$ 15.85		$ 7.69
Number of units vested								879
Award vesting rights, percentage		81.60%				84.00%
Vesting May 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units granted			500
Units granted, weighted average grant date fair value (usd per share)			$ 18.75
Vesting March 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units granted			1,080
Units granted, weighted average grant date fair value (usd per share)			$ 18.75