Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows From Operating Activities:
Net Earnings	$ 95,419	$ 131,896	$ 31,078
Net Earnings	79,874	116,849	15,640
Adjustments to reconcile net earnings to net cash flows from operating activities:
Depreciation and amortization	268,194	242,033	222,861
Deferred income tax expense	130,528	63,805	16,451
Net unrealized (gains) losses on commodity derivatives	2,875	1,577	5,188
Realized (gains) on available-for-sale securities	(27,161)	(19,517)	(16,060)
Stock based compensation expense	6,194	5,634	4,863
Regulatory disallowances and restructuring costs	27,036	15,011	167,471
Allowance for equity funds used during construction	(9,516)	(4,949)	(10,430)
Other, net	2,329	3,060	3,934
Changes in certain assets and liabilities:
Accounts receivable and unbilled revenues	(1,846)	2,543	(3,298)
Materials, supplies, and fuel stock	1,473	(4,169)	(180)
Other current assets	32,298	(2,469)	29,370
Other assets	(5,486)	(42,864)	2,369
Accounts payable	14,468	3,159	(32,269)
Accrued interest and taxes	(327)	3,345	4,957
Other current liabilities	(6,513)	(12,509)	2,633
Other liabilities	(5,503)	29,868	(42,064)
Net cash flows from operating activities	524,462	415,454	386,874
Cash Flows From Investing Activities:
Additions to utility and non-utility plant	(500,461)	(600,076)	(558,589)
Proceeds from sales of available-for-sale securities	637,492	522,601	252,174
Purchases of available-for-sale securities	(650,284)	(538,383)	(262,548)
Return of principal on PVNGS lessor notes	0	8,547	21,694
Investments in NMRD	(4,077)	0	0
Disbursements from NMRD	12,415	0	0
Investment in Westmoreland Loan	0	(122,250)	0
Principal repayments on Westmoreland Loan	38,360	30,000	0
Other, net	392	186	2,741
Net cash flows from investing activities	(466,163)	(699,375)	(544,528)
Cash Flows From Financing Activities:
Short-term loan		100,000	50,000
Repayment of short-term loan	0	(150,000)	0
Revolving credit facilities borrowings (repayments), net	18,300	86,500	95,000
Long-term borrowings	317,000	603,500	463,605
Repayment of long-term debt	(274,070)	(303,793)	(333,066)
Proceeds from stock option exercise	1,739	7,028	5,619
Awards of common stock	(13,929)	(15,451)	(17,720)
Dividends paid	(77,792)	(70,623)	(64,251)
Valencia’s transactions with its owner	(17,742)	(17,006)	(17,049)
Amounts received under transmission interconnection arrangements	11,879	7,171	27
Refunds paid under transmission interconnection arrangements	(21,290)	(2,830)	(2,338)
Other, net	(2,942)	(2,104)	(4,396)
Net cash flows from financing activities	(58,847)	242,392	175,431
Change in Cash and Cash Equivalents	(548)	(41,529)	17,777
Cash and Cash Equivalents at Beginning of Period	4,522	46,051	28,274
Cash and Cash Equivalents at End of Period	3,974	4,522	46,051
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	120,955	115,043	103,382
Income taxes paid (refunded), net	625	(307)	(1,890)
Supplemental schedule of noncash investing and financing activities:
(Increase) decrease in accrued plant additions	(25,261)	18,345	(19,080)
Contribution of utility plant to NMRD	24,829
Public Service Company of New Mexico
Cash Flows From Operating Activities:
Net Earnings	87,413	91,938	(324)
Net Earnings	72,396	77,419	(15,234)
Adjustments to reconcile net earnings to net cash flows from operating activities:
Depreciation and amortization	180,500	166,047	150,538
Deferred income tax expense	82,549	53,119	(2,836)
Net unrealized (gains) losses on commodity derivatives	2,875	1,577	5,188
Realized (gains) on available-for-sale securities	(27,161)	(19,517)	(16,060)
Regulatory disallowances and restructuring costs	27,036	15,011	167,471
Allowance for equity funds used during construction	(8,664)	(4,163)	(10,430)
Other, net	2,615	3,046	2,794
Changes in certain assets and liabilities:
Accounts receivable and unbilled revenues	(419)	4,769	(2,515)
Materials, supplies, and fuel stock	3,542	(3,924)	381
Other current assets	32,775	1,127	23,693
Other assets	15,121	(23,880)	4,194
Accounts payable	9,736	5,614	(31,139)
Accrued interest and taxes	21,523	(9,601)	(5,343)
Other current liabilities	(11,099)	(12,136)	(275)
Other liabilities	(9,389)	20,119	(33,503)
Net cash flows from operating activities	408,953	289,146	251,834
Cash Flows From Investing Activities:
Additions to utility and non-utility plant	(309,142)	(445,464)	(404,840)
Proceeds from sales of available-for-sale securities	637,492	522,601	252,174
Purchases of available-for-sale securities	(650,284)	(538,383)	(262,548)
Return of principal on PVNGS lessor notes	0	8,547	21,694
Other, net	33	171	2,935
Net cash flows from investing activities	(321,901)	(452,528)	(390,585)
Cash Flows From Financing Activities:
Revolving credit facilities borrowings (repayments), net	(21,200)	61,000	0
Long-term borrowings	257,000	321,000	313,605
Repayment of long-term debt	(232,000)	(271,000)	(214,300)
Equity contribution from parent	0	28,142	175,000
Dividends paid	(61,223)	(4,670)	(94,968)
Valencia’s transactions with its owner	(17,742)	(17,006)	(17,049)
Amounts received under transmission interconnection arrangements	11,879	7,171	27
Refunds paid under transmission interconnection arrangements	(21,290)	(2,830)	(2,338)
Other, net	(1,692)	(1,239)	(3,568)
Net cash flows from financing activities	(86,268)	120,568	156,409
Change in Cash and Cash Equivalents	784	(42,814)	17,658
Cash and Cash Equivalents at Beginning of Period	324	43,138	25,480
Cash and Cash Equivalents at End of Period	1,108	324	43,138
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	77,960	82,514	69,936
Income taxes paid (refunded), net	(23,391)	(967)	(1,450)
Supplemental schedule of noncash investing and financing activities:
(Increase) decrease in accrued plant additions	(11,792)	22,433	(17,469)
Texas-New Mexico Power Company
Cash Flows From Operating Activities:
Net Earnings	35,559	41,672	41,963
Adjustments to reconcile net earnings to net cash flows from operating activities:
Depreciation and amortization	64,939	62,866	57,909
Deferred income tax expense	27,275	12,662	20,883
Allowance for equity funds used during construction	(900)	(800)	0
Allowance for equity funds used during construction and other, net	(1,120)	(772)	18
Changes in certain assets and liabilities:
Accounts receivable and unbilled revenues	(1,427)	(2,226)	(783)
Materials, supplies, and fuel stock	(2,069)	(245)	(561)
Other current assets	(1,253)	(621)	3,928
Other assets	(20,967)	(19,126)	(2,310)
Accounts payable	2,419	(2,040)	(1,782)
Accrued interest and taxes	(15,962)	12,690	4,317
Other current liabilities	(2,236)	298	1,019
Other liabilities	1,334	6,822	(9,823)
Net cash flows from operating activities	86,492	111,980	114,778
Cash Flows From Investing Activities:
Additions to utility and non-utility plant	(145,495)	(122,518)	(124,584)
Net cash flows from investing activities	(145,495)	(122,518)	(124,584)
Cash Flows From Financing Activities:
Revolving credit facilities borrowings (repayments), net	0	(59,000)	54,000
Short-term borrowings (repayments) - affiliate, net	(4,600)	(7,200)	(10,900)
Long-term borrowings	60,000	60,000	0
Equity contribution from parent	50,000	50,000	0
Dividends paid	(44,389)	(31,817)	(33,248)
Other, net	(979)	(775)	(46)
Net cash flows from financing activities	60,032	11,208	9,806
Change in Cash and Cash Equivalents	1,029	670	0
Cash and Cash Equivalents at Beginning of Period	671	1	1
Cash and Cash Equivalents at End of Period	1,700	671	1
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	29,251	26,766	26,216
Income taxes paid (refunded), net	21,436	660	290
Supplemental schedule of noncash investing and financing activities:
(Increase) decrease in accrued plant additions	$ (15,737)	$ (1,271)	$ (5)