Share-Based Compensation Expense (Narrative) (Details) $ in Millions	3 Months Ended
Mar. 31, 2019 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation costs related to the outstanding or unvested stock-based compensation awards	$ 8.7
Weighted average remaining vesting period	2 years
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate share-based awards granted \| shares	195,031
Aggregate fair value of share-based awards granted	$ 3.9

Unrecognized cost of unvested share-based compensation awards.

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

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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Value, before forfeitures, of stock or other type of equity granted of any equity-based compensation plan other than an employee stock ownership plan (ESOP).

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