Lease Commitments - Schedule of Future Expected Lease Payments (Details) $ in Thousands	Sep. 30, 2021 USD ($)
Financing
Remainder of 2021	$ 1,532
2022	5,980
2023	5,607
2024	4,421
2025	2,710
Later years	2,752
Total minimum lease payments	23,002
Less: Imputed interest	1,027
Lease liabilities as of September 30, 2021	21,975
Operating
Remainder of 2021	935
2022	28,467
2023	19,665
2024	8,833
2025	7,685
Later years	27,816
Total minimum lease payments	93,401
Less: Imputed interest	10,065
Lease liabilities as of September 30, 2021	83,336
PNM
Financing
Remainder of 2021	709
2022	2,767
2023	2,649
2024	1,972
2025	1,164
Later years	1,335
Total minimum lease payments	10,596
Less: Imputed interest	337
Lease liabilities as of September 30, 2021	10,259
Operating
Remainder of 2021	334
2022	26,266
2023	17,735
2024	7,908
2025	6,946
Later years	27,520
Total minimum lease payments	86,709
Less: Imputed interest	9,310
Lease liabilities as of September 30, 2021	77,399
TNMP
Financing
Remainder of 2021	800
2022	3,125
2023	2,906
2024	2,438
2025	1,545
Later years	1,417
Total minimum lease payments	12,231
Less: Imputed interest	685
Lease liabilities as of September 30, 2021	11,546
Operating
Remainder of 2021	538
2022	1,990
2023	1,750
2024	877
2025	702
Later years	76
Total minimum lease payments	5,933
Less: Imputed interest	366
Lease liabilities as of September 30, 2021	$ 5,567

Finance Lease, Liability, to be Paid, after Year Four

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- Definition

Lessee, Operating Lease, Liability, to be Paid, after Year Four

+ References

No definition available.

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No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Present value of lessee's discounted obligation for lease payments from finance lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918701-209980

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977

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- Definition

Amount of lessee's undiscounted obligation for lease payments for finance lease.

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Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in remainder of current fiscal year.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918701-209980

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Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for finance lease.

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- References

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Amount of lessee's undiscounted obligation for lease payment for operating lease.

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease having initial or remaining lease term in excess of one year to be paid in remainder of current fiscal year.

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease.

+ References

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977

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