EARNINGS PER SHARE - Reconciliation of weighted average shares outstanding (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
EARNINGS PER SHARE
Net income available for stockholders:	$ 39,388	$ 35,076
Less: Dividends paid	(22,986)	(22,015)
Undistributed earnings	$ 16,402	$ 13,061
Basic shares outstanding:
Common stock	211,434	211,873
Restricted shares of common stock	3,741	4,321
Basic shares outstanding, Total	215,175	216,194
Diluted shares outstanding:
Common stock	211,434	211,873
Dilutive effect of stock based awards	1,039	1,331
Diluted shares outstanding excluding restricted shares of common stock, Total	212,473	213,204
Restricted shares of common stock	3,741	4,321
Diluted shares outstanding, Total	216,214	217,525