XML 53 R41.htm IDEA: XBRL DOCUMENT v3.8.0.1
VARIABLE INTEREST ENTITIES - Consolidated Entities (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Dec. 31, 2016
Consolidated Variable Interest Entities          
Noncontrolling interest included in consolidated statements of financial position (in dollars) $ 110,556   $ 110,556   $ 109,147
Interest expense (in dollars) $ 37,289 $ 37,041 $ 109,937 $ 108,385  
Primary Beneficiary | Springerville Partnership          
Consolidated Variable Interest Entities          
Equity interest (as a percent)     51.00%    
General partner interest (as a percent)     1.00%    
Ownership interest held by noncontrolling interest (as a percent) 49.00%   49.00%   49.00%
Noncontrolling interest included in consolidated statements of financial position (in dollars) $ 110,600   $ 110,600   $ 109,100
Springerville Partnership | Springerville Unit 3 Holding LLC          
Consolidated Variable Interest Entities          
Ownership interest held by parent (as a percent) 100.00%   100.00%    
Springerville Partnership | Primary Beneficiary          
Consolidated Variable Interest Entities          
Depreciation and amortization (in dollars) $ 4,500 5,300 $ 15,100 15,800  
Interest expense (in dollars) 7,100 $ 7,600 21,300 $ 22,800  
Springerville Partnership | Primary Beneficiary | Electric Plant          
Consolidated Variable Interest Entities          
Assets of variable interest entity included in consolidated statements of financial position (in dollars) 817,200   817,200   832,300
Springerville Partnership | Primary Beneficiary | Long-term debt          
Consolidated Variable Interest Entities          
Liabilities of variable interest entity included in consolidated statements of financial position (in dollars) 431,700   431,700   472,100
Springerville Partnership | Primary Beneficiary | Accrued interest included in long-term debt          
Consolidated Variable Interest Entities          
Liabilities of variable interest entity included in consolidated statements of financial position (in dollars) $ 5,000   $ 5,000   $ 13,400
Springerville Partnership | Primary Beneficiary | Springerville Unit 3 Lease          
Consolidated Variable Interest Entities          
Percentage of financial and other support provided     100.00%