Lease Commitments - Schedule of Future Expected Lease Payments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing
Remainder of 2019	$ 586
2020	982
2021	947
2022	912
2023	802
Later years	696
Total minimum lease payments	4,925
Less: Imputed interest	698
Lease liabilities as of June 30, 2019	4,227
Operating
Remainder of 2019	12,877
2020	30,543
2021	29,152
2022	28,255
2023	18,879
Later years	43,490
Total minimum lease payments	163,196
Less: Imputed interest	19,336
Lease liabilities as of June 30, 2019	143,860
Operating leases
Remainder of 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
PNM
Financing
Remainder of 2019	281
2020	470
2021	454
2022	437
2023	415
Later years	316
Total minimum lease payments	2,373
Less: Imputed interest	314
Lease liabilities as of June 30, 2019	2,059
Operating
Remainder of 2019	10,529
2020	27,033
2021	26,499
2022	26,235
2023	17,457
Later years	42,328
Total minimum lease payments	150,081
Less: Imputed interest	18,248
Lease liabilities as of June 30, 2019	131,833
Operating leases
Remainder of 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
TNMP
Financing
Remainder of 2019	305
2020	511
2021	493
2022	475
2023	388
Later years	381
Total minimum lease payments	2,553
Less: Imputed interest	385
Lease liabilities as of June 30, 2019	2,168
Operating
Remainder of 2019	2,014
2020	2,993
2021	2,398
2022	1,846
2023	1,281
Later years	1,151
Total minimum lease payments	11,683
Less: Imputed interest	367
Lease liabilities as of June 30, 2019	$ 11,316
Operating leases
Remainder of 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