Short-term Debt and Credit Lines (Total Short-term Debt) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Short-term Debt
Total short-term debt	$ 75,927us-gaap_ShortTermBorrowings	$ 70,045us-gaap_ShortTermBorrowings
Notes payable to banks
Short-term Debt
Total short-term debt	5,977	4,795
Commercial paper
Short-term Debt
Total short-term debt	$ 69,950	$ 65,250

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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Name:	us-gaap_ShortTermBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant