INCOME TAXES (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Current
Federal	$ (3,639)	$ 12,777	$ 18,274	$ 25,540
State	(1,683)	3,170	5,593	5,752
Total current	(5,322)	15,947	23,867	31,292
Deferred
Federal	15,680	(5,937)	15,948	(9,123)
State	398	(2,410)	2,000	(4,054)
Total deferred	16,078	(8,347)	17,948	(13,177)
Investment tax credits	(48)	(36)	(97)	(73)
Total income tax expense	$ 10,708	$ 7,564	$ 41,718	$ 18,042
Combined statutory federal and state income tax rate (in hundredths)	40.40%	40.40%	40.40%	40.40%
Effective book income tax rate (in hundredths)	43.10%	39.70%	38.70%	39.70%