CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (UNAUDITED) (Parenthetical) - shares shares in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2019
Statement Of Stockholders Equity [Abstract]
Treasury stock shares (in shares)	75,737	125,888
Options exercised and awards vested, net of shares withheld for employee taxes (in shares)	47,712	47,712

Number of share options (or share units) exercised during the current period.

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