Annual report pursuant to Section 13 and 15(d)

Leased Properties and Leases - Additional Information (Details)

v3.6.0.2
Leased Properties and Leases - Additional Information (Details)
customer in Thousands, $ in Thousands
12 Months Ended
Dec. 31, 2016
customer
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Apr. 01, 2015
USD ($)
Nov. 01, 2012
USD ($)
Public Service Company of New Mexico [Member]          
Sale Leaseback Transaction [Line Items]          
Undivided interest         40.00%
Lease agreement       $ 7,700  
Number of customers served | customer 500        
Intangible asset amortized         $ 1,100
Lease Revenue [Member]          
Sale Leaseback Transaction [Line Items]          
Amortization of intangible assets   $ 73 $ 292