Lease Commitments - Schedule of Future Expected Lease Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing
2020	$ 1,925
2021	1,807
2022	1,866
2023	1,624
2024	1,153
Later years	1,249
Total minimum lease payments	9,624
Less: Imputed interest	885
Lease liabilities as of December 31, 2019	8,739
Operating
2020	30,660
2021	29,316
2022	28,473
2023	19,423
2024	8,833
Later years	35,489
Total minimum lease payments	152,194
Less: Imputed interest	17,614
Lease liabilities as of December 31, 2019	134,580
Operating leases
2019		$ 31,772
2020		30,404
2021		29,012
2022		28,175
2023		18,868
Later years		43,489
Total minimum lease payments		181,720
Public Service Company of New Mexico
Financing
2020	857
2021	803
2022	830
2023	767
2024	505
Later years	723
Total minimum lease payments	4,485
Less: Imputed interest	430
Lease liabilities as of December 31, 2019	4,055
Operating
2020	27,028
2021	26,576
2022	26,266
2023	17,735
2024	7,908
Later years	34,466
Total minimum lease payments	139,979
Less: Imputed interest	16,060
Lease liabilities as of December 31, 2019	123,919
Operating leases
2019		27,691
2020		27,000
2021		26,462
2022		26,217
2023		17,447
Later years		42,329
Total minimum lease payments		167,146
Texas-New Mexico Power Company
Financing
2020	998
2021	934
2022	966
2023	819
2024	648
Later years	526
Total minimum lease payments	4,891
Less: Imputed interest	444
Lease liabilities as of December 31, 2019	4,447
Operating
2020	3,078
2021	2,448
2022	1,996
2023	1,508
2024	877
Later years	765
Total minimum lease payments	10,672
Less: Imputed interest	880
Lease liabilities as of December 31, 2019	$ 9,792
Operating leases
2019		3,664
2020		3,102
2021		2,324
2022		1,795
2023		1,279
Later years		1,150
Total minimum lease payments		$ 13,314