Consolidated Statements of Changes in Stockholders' Equity (Parentheticals) - shares shares in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Purchase of treasury shares (in shares)	820	588	1,051

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

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