Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_StockRepurchasedDuringPeriodValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Share Repurchases - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended		9 Months Ended
	Sep. 30, 2019	Jan. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Nov. 01, 2017
Equity Class Of Treasury Stock [Line Items]
Stock repurchase program, authorized amount					$ 500.0
Open market share repurchase	$ 150.0	$ 100.0
Payments for share repurchase			$ 250.0	$ 200.0
Evergreen Share Repurchase Program
Equity Class Of Treasury Stock [Line Items]
Payments for share repurchase	50.0
Repurchase Program
Equity Class Of Treasury Stock [Line Items]
Payments for share repurchase	100.0
Remaining amount of share repurchase program	$ 210.0		$ 210.0