Stock-based Compensation Narrative - Restricted Stock Awards (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Jun. 30, 2019	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares withheld for tax withholding obligation	7,000
Restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock awards vested		$ 2.1
Shares withheld for tax withholding obligation		7,365
Unrecognized stock-based compensation expense		$ 7.3
Compensation cost not yet recognized, period		3 years 2 months 12 days
Minimum [Member] \| Restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		1 year
Maximum [Member] \| Restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents 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 (i)
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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

+ 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
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-URI http://asc.fasb.org/extlink&oid=116856206&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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Number of shares used to settle grantee's tax withholding obligation for award under share-based payment arrangement.

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