Basis and Summary of Significant Accounting Policies - Calculation of Dilutive Stock Awards (Details) - shares shares in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Accounting Policies [Abstract]
Weighted Average Shares Outstanding (in shares)	67,294	70,105
Dilutive Effect of Share-Based Awards (in shares)	1,479	1,913
Weighted Average Shares Outstanding Assuming Dilution (in shares)	68,773	72,018
Anti-dilutive securities excluded from the computation of earnings per share assuming dilution (in shares)	443	187

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
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-SubTopic 10
-Section 45
-Paragraph 16
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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109260490&loc=d3e1448-109256

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