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INCOME TAXES - Reconciliation of Income Tax Expense with Federal Income Taxes at the Statutory Rate (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Operating Loss Carryforwards [Line Items]      
Federal statutory income tax rate 35.00% 35.00% 35.00%
Reconciliation of income tax expense with federal income taxes at the statutory rate      
Federal income tax at the 35% statutory rate $ 356,670 $ 437,746 $ 467,035
State income taxes, net of federal income tax benefit 25,993 29,507 31,263
Foreign rate difference 21,077 12,041 20,318
Other - net 11,150 (405) 3,474
Income tax expense $ 386,220 $ 465,531 $ 522,090
Effective tax rate 37.90% 37.20% 39.10%
Clean energy credit [Member]      
Reconciliation of income tax expense with federal income taxes at the statutory rate      
Clean energy credit $ (28,670) $ (13,358) $ 0