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Years Subject to Examination (Details) | 12 Months Ended
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Dec. 31, 2018
Federal |
Income Tax Examination |
Income tax return jurisdictions and years that remain subject to examination | 2015, 2016 and 2017
Montana |
Income Tax Examination |
Income tax return jurisdictions and years that remain subject to examination | 2015, 2016 and 2017
Idaho |
Income Tax Examination |
Income tax return jurisdictions and years that remain subject to examination | 2015, 2016 and 2017
Utah |
Income Tax Examination |
Income tax return jurisdictions and years that remain subject to examination | 2015, 2016 and 2017
Colorado |
Income Tax Examination |
Income tax return jurisdictions and years that remain subject to examination | 2014, 2015, 2016 and 2017
Arizona |
Income Tax Examination |
Income tax return jurisdictions and years that remain subject to examination | 2017

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