EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Earnings Per Share
Net income available for stockholders:	$ 66,040	$ 83,111	$ 219,055	$ 221,800
Less: Dividends paid	(17,540)	(11,715)	(52,623)	(32,501)
Undistributed earnings	$ 48,500	$ 71,396	$ 166,432	$ 189,299
Basic shares outstanding:
Common stock	210,627	213,390	210,664	213,191
Restricted shares of common stock	4,524	4,520	4,547	4,561
Basic shares outstanding, Total	215,151	217,910	215,211	217,752
Diluted shares outstanding:
Common stock	210,627	213,390	210,664	213,191
Dilutive effect of options	1,494	2,389	1,608	2,681
Weighted average number of diluted shares outstanding including common stock and dilutive effect of stock option	212,121	215,779	212,272	215,872
Restricted shares of common stock	4,524	4,520	4,547	4,561
Basic and diluted shares outstanding, Total	216,645	220,299	216,819	220,433
Common stock:
Distributed earnings	$ 0.08	$ 0.05	$ 0.24	$ 0.15
Undistributed earnings	$ 0.23	$ 0.33	$ 0.78	$ 0.87
Basic earnings per share total	$ 0.31	$ 0.38	$ 1.02	$ 1.02
Restricted shares of common stock:
Distributed earnings	$ 0.07	$ 0.04	$ 0.21	$ 0.12
Undistributed earnings	$ 0.22	$ 0.32	$ 0.75	$ 0.84
Earnings per share basic restricted shares of common stock	$ 0.29	$ 0.36	$ 0.96	$ 0.96
Common Stock:
Distributed earnings	$ 0.08	$ 0.05	$ 0.24	$ 0.15
Undistributed earnings	$ 0.22	$ 0.33	$ 0.77	$ 0.86
Diluted earnings per share, Total	$ 0.30	$ 0.38	$ 1.01	$ 1.01