Changes in Stockholders' Equity (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Sep. 30, 2020
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)	970,141

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

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Period Type:	duration