STOCKHOLDERS' EQUITY (Details) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended							12 Months Ended
	Dec. 31, 2011	Oct. 31, 2011	Jul. 31, 2011	Jun. 30, 2011	Apr. 30, 2011	Mar. 31, 2011	Feb. 28, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
STOCKHOLDERS' EQUITY
Common stock outstanding (in shares)	157,320,070							157,320,070	156,955,746	154,227,746
Number of shares of common stock authorized	175,772,173							175,772,173	175,772,173
Common stock issued (in shares)	157,320,070							157,320,070	156,955,746
Number of votes for each share of common stock held								one vote
Stock options exercised (in shares)								364,324	2,728,000	2,072,533
Aggregate consideration of common stock issued								$ 5,352	$ 42,812	$ 3,398
Dividends declared and paid
Dividends declared per share (in dollars per share)		$ 0.22	$ 0.22		$ 0.22		$ 0.16	$ 0.82	$ 0.51
Dividends paid per share (in dollars per share)	$ 0.22	$ 0.22		$ 0.22		$ 0.16
Dividends declared		34,610	34,606		34,599		25,115
Dividends paid	$ 34,610	$ 34,606		$ 34,599		$ 25,115		$ 128,930	$ 80,444