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v3.7.0.1

Debt - Industrial Revenue Bonds (Details) | Mar. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
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Maximum [Member] | Short-term Debt [Member] | Industrial revenue bonds due 2028 [Member] |  |  |
Short-term Debt [Line Items] |  |  |
Effective interest rate (percent) | 12.00% | 12.00% | 12.00%

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- Definition Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. + References 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(a)(1)) -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 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399 + Details
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