CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
PROPERTY, PLANT AND EQUIPMENT (Notes 1, 6 and 10)
Accumulated depreciation of Palo Verde sale leaseback	$ 225,925	$ 222,055
Accumulated amortization on intangible assets	439,703	411,543
Accumulated amortization on nuclear fuel	$ 146,057	$ 133,950
EQUITY (Note 7)
Common stock, par value
Common stock, authorized shares	150,000,000	150,000,000
Common stock, issued shares	110,280,703	109,837,957
Treasury stock at cost, shares	98,944	95,192