NET INCOME PER SHARE (DILUTED SHARES TABLE) (DETAILS)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Shares used in basic earnings per share calculation	50,439,000	50,732,000	51,861,000	52,347,000	53,262,000	54,093,000	55,125,000	56,493,000	51,338,000	54,738,000	56,669,000
Effect of dilutive securities:
Stock options									417	378	727
Restricted stock units									489	424	564
Performance-based restricted stock units											3
Total effects of dilutive securities									906	802	1,294
Shares used in dilutive earnings per share calculation	51,465,000	51,678,000	52,628,000	53,217,000	54,196,000	54,905,000	55,712,000	57,418,000	52,244,000	55,540,000	57,963,000