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Pension and Other Postretirement Benefits - Actuarial (Gain) Loss Results (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2016 | Dec. 31, 2015
Public Service Company of New Mexico [Member] | Pension Plan [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Discount rates | $ 41,849 | $ (45,918)
Claims, contributions, and demographic experience | (334) | 2,778
Other assumption and experience | (2,052) | 4,989
Actuarial (gain) loss | 39,463 | (38,151)
Public Service Company of New Mexico [Member] | Other Postretirement Benefits [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Discount rates | 6,569 | (7,345)
Claims, contributions, and demographic experience | 19,562 | 780
Assumed participation rate | (6,335) | 0
Mortality rate | (691) | 0
Medical benefits | (1,228) | 0
Actuarial (gain) loss | 17,877 | (6,565)
Texas-New Mexico Power Company [Member] | Pension Plan [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Discount rates | 5,055 | (6,090)
Claims, contributions, and demographic experience | (556) | 877
Other assumption and experience | (181) | 56
Actuarial (gain) loss | 4,318 | (5,157)
Texas-New Mexico Power Company [Member] | Other Postretirement Benefits [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Discount rates | 1,112 | (1,322)
Claims, contributions, and demographic experience | (102) | 747
Assumed participation rate | (1,013) | 0
Mortality rate | (93) | 0
Medical benefits | 0 | 0
Actuarial (gain) loss | $ (96) | $ (575)

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- Definition Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Gain or Loss -URI http://asc.fasb.org/extlink&oid=49168827 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 + Details
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