Number of shares that have been repurchased during the period and are being held in treasury.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_TreasuryStockSharesAcquired
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Equity - Common Stock Repurchase Plan (Details) $ in Millions				12 Months Ended
	Aug. 08, 2018 shares	Mar. 26, 2018 shares	May 25, 2017	Dec. 31, 2019 shares	Dec. 31, 2018 shares	Dec. 31, 2017 shares	May 10, 2018 USD ($)	Dec. 14, 2017 USD ($)
Common Stock
Share buybacks					7,098,637	461,173
Income tax withholding				186,786	332,503
Number of shares repurchased (in shares)	2,500,000	5,100,000		186,786	7,431,140	461,173
Stockholders' Equity Note, Stock Split, Conversion Ratio			66,498.762
Maximum
Common Stock
Common stock repurchase authorized amount \| $							$ 25.0	$ 50.0