EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Basic earnings per common share
Net earnings	$ 135,369	$ 170,719
Less: Distributed and undistributed earnings allocated to participating securities	(1,155)	(2,472)
Net earnings allocable to common shares	134,214	168,247
Basic weighted average common shares outstanding	133,464,000	139,323,000
Basic earnings per common share	$ 1.01	$ 1.21
Diluted earnings per common share
Net earnings	135,369	170,719
Less: Distributed and undistributed earnings allocated to participating securities	(1,149)	(2,459)
Net earnings allocable to common shares	$ 134,220	$ 168,260
Basic weighted average common shares outstanding	133,464,000	139,323,000
Effect of dilutive options	836,000	844,000
Diluted weighted average common shares outstanding	134,300,000	140,167,000
Diluted earnings per common share	$ 1.00	$ 1.20
Potential common stock equivalents excluded from computation of diluted earnings per share	2,400,000	7,500,000