Lease Commitments - Finance Lease Balance Sheet Information (Details) $ in Thousands	Jun. 30, 2019 USD ($)
Financing leases:
Non-utility property	$ 4,821
Accumulated depreciation	(282)
Non-utility property, net	4,539
Other current liabilities	789
Other deferred credits	3,438
PNM
Financing leases:
Non-utility property	2,516
Accumulated depreciation	(143)
Non-utility property, net	2,373
Other current liabilities	381
Other deferred credits	1,678
TNMP
Financing leases:
Non-utility property	2,305
Accumulated depreciation	(139)
Non-utility property, net	2,166
Other current liabilities	408
Other deferred credits	$ 1,760