Changes in Stockholders' Equity (Narrative) (Details) $ in Millions	3 Months Ended
Mar. 31, 2020 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, outstanding balance authorized to be repurchased	$ 245.0
ASR Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated share repurchases, settlement (payment) or receipt	$ 55.0
Stock repurchased and retired during period (in shares) \| shares	970,141

Number of shares that have been repurchased and retired during the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-SubTopic 10
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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