Consolidated Statement of Changes in Shareholders' Equity (Parenthetical) (Parentheticals) - shares	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Statement of Stockholders' Equity [Abstract]
Common shares issued from treasury stock for stock-based compensation (in shares)	5,284,974	8,447,558
Common shares repurchased (in shares)	12,804,035	0

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
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Section S99
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration