Debt Long-Term Debt (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total Long-Term Debt and Capital Lease Obligations	$ 11,426	$ 16,830
Less current portion	(4,155)	(6,558)
Long-term Debt	7,271	10,272
Long-term Debt, Fiscal Year Maturity [Abstract]
2017	4,155
2018	1,672
2019	996
2020	811
2021	751
After 2021	$ 3,041
1.85% Note \| Unsecured Debt
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.85%
Debt Instrument, Periodic Payment	$ 798
Total Long-Term Debt and Capital Lease Obligations	$ 0	1,586
1.43% Note \| Unsecured Debt
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.43%
Debt Instrument, Periodic Payment	$ 134
Total Long-Term Debt and Capital Lease Obligations	0	267
2.03% to 30.63% capital leases, secured by equipment, various maturities \| Capital Lease Obligations
Debt Instrument [Line Items]
Total Long-Term Debt and Capital Lease Obligations	$ 11,426	$ 14,977

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

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