Earnings Per Share Earnings Per Share (Narrative) (Details) - Performance-based restricted stock units [Member]	Sep. 30, 2018 shares
Minimum [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Performance-based restricted stock units that could be issued upon vesting	0
Maximum [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Performance-based restricted stock units that could be issued upon vesting	600,000

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.

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration