Lease Commitments Schedule of Rent Expense (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
PNMR [Member]
Operating lease expense [Line Items]
Operating Leases, Rent Expense, Net	$ 86,323	$ 79,491	$ 77,697
Public Service Company of New Mexico [Member]
Operating lease expense [Line Items]
Operating Leases, Rent Expense, Net	78,422	71,209	75,865
Texas-New Mexico Power Company [Member]
Operating lease expense [Line Items]
Operating Leases, Rent Expense, Net	$ 3,606	$ 3,737	$ 2,493